[[pp. 61893-61942]] Amendments for Testing and Monitoring Provisions

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

[Federal Register: October 17, 2000 (Volume 65, Number 201)]
[Rules and Regulations]
[Page 61893-61942]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr17oc00-13]

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BILLING CODE 6560-50-P

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Method 6A--Determination of Sulfur Dioxide, Moisture, and Carbon
Dioxide From Fossil Fuel Combustion Sources

Note: This method does not include all of the specifications
(e.g., equipment and supplies) and procedures (e.g., sampling and
analytical) essential to its performance. Some material is
incorporated by reference from other methods in this part.
Therefore, to obtain reliable results, persons using this method
should have a thorough knowledge of at least the following
additional test methods: Method 1, Method 2, Method 3, Method 5,
Method 6, and Method 19.

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
SO2............................... 7449-09-05 3.4 mg SO2/m3
(2.12 x 10-7 lb/
ft3)
CO2............................... 124-38-9 N/A
H2O............................... 7732-18-5 N/A
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of sulfur dioxide (SO2) emissions from fossil fuel
combustion sources in terms of concentration (mg/dscm or lb/dscf) and
in terms of emission rate (ng/J or lb/106 Btu) and for the
determination of carbon dioxide (CO2) concentration
(percent). Moisture content (percent), if desired, may also be
determined by this method.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 A gas sample is extracted from a sampling point in the stack.
The SO2 and the sulfur trioxide, including those fractions
in any sulfur acid mist, are separated. The SO2 fraction is
measured by the barium-thorin titration method. Moisture and
CO2 fractions are collected in the same sampling train, and
are determined gravimetrically.

3.0 Definitions. [Reserved]

4.0 Interferences

Same as Method 6, Section 4.0.

5.0 Safety

6.0 Equipment and Supplies

6.1 Sample Collection. Same as Method 6, Section 6.1, with the
exception of the following:
6.1.1 Sampling Train. A schematic of the sampling train used in
this method is shown in Figure 6A-1.
6.1.1.1 Impingers and Bubblers. Two 30=ml midget impingers with a
1=mm restricted tip and two 30=ml midget bubblers with unrestricted
tips. Other types of impingers and bubblers (e.g., Mae West for
SO2 collection and rigid cylinders containing Drierite for
moisture absorbers), may be used with proper attention to reagent
volumes and levels, subject to the approval of the Administrator.
6.1.1.2 CO2 Absorber. A sealable rigid cylinder or
bottle with an inside diameter between 30 and 90 mm , a length between
125 and 250 mm, and appropriate connections at both ends. The filter
may be a separate heated unit or may be within the heated portion of
the probe. If the filter is within the sampling probe, the filter
should not be within 15 cm of the probe inlet or any unheated section
of the probe, such as the connection to the first bubbler. The probe
and filter should be heated to at least 20 deg.C (68 deg.F) above the
source temperature, but not greater than 120 deg.C (248 deg.F). The
filter temperature (i.e., the sample gas temperature) should be
monitored to assure the desired temperature is maintained. A heated
Teflon connector may be used to connect the filter holder or probe to
the first impinger.

Note: For applications downstream of wet scrubbers, a heated
out-of-stack filter (either borosilicate glass wool or glass fiber
mat) is necessary.

6.2 Sample Recovery. Same as Method 6, Section 6.2.
6.3 Sample Analysis. Same as Method 6, Section 6.3, with the
addition of a balance to measure within 0.05 g.

7.0 Reagents and Standards

Note: Unless otherwise indicated, all reagents must conform to
the specifications established by the Committee on Analytical
Reagents of the American Chemical Society. Where such specifications
are not available, use the best available grade.

7.1 Sample Collection. Same as Method 6, Section 7.1, with the
addition of the following:
7.1.1 Drierite. Anhydrous calcium sulfate (CaSO4)
desiccant, 8 mesh, indicating type is recommended.

Note: Do not use silica gel or similar desiccant in this
application.

7.1.2 CO2 Absorbing Material. Ascarite II. Sodium
hydroxide-coated silica, 8- to 20-mesh.
7.2 Sample Recovery and Analysis. Same as Method 6, Sections 7.2
and 7.3, respectively.

8.0 Sample Collection, Preservation, Transport, and Storage

8.1 Preparation of Sampling Train.
8.1.1 Measure 15 ml of 80 percent isopropanol into the first
midget bubbler and 15 ml of 3 percent hydrogen peroxide into each of
the two midget impingers (the second and third vessels in the train) as
described in Method 6, Section 8.1. Insert the glass wool into the top
of the isopropanol bubbler as shown in Figure 6A-1. Place about 25 g of
Drierite into the second midget bubbler (the fourth vessel in the
train). Clean the outside of the bubblers and impingers and allow the
vessels to reach room temperature. Weigh the four vessels
simultaneously to the nearest 0.1 g, and record this initial weight
(mwi).
8.1.2 With one end of the CO2 absorber sealed, place
glass wool into the cylinder to a depth of about 1 cm (0.5 in.). Place
about 150 g of CO2 absorbing material in the cylinder on top
of the glass wool, and fill the remaining space in the cylinder with
glass wool. Assemble the cylinder as shown in Figure 6A-2. With the
cylinder in a horizontal position, rotate it around the horizontal
axis. The CO2 absorbing material should remain in position
during the rotation, and no open spaces or channels should be formed.
If necessary, pack more glass wool into the cylinder to make the
CO2 absorbing material stable. Clean the outside of the
cylinder of loose dirt and moisture and allow the cylinder to reach
room temperature. Weigh the cylinder to the nearest 0.1 g, and record
this initial weight (mai).

[[Page 61897]]

8.1.3 Assemble the train as shown in Figure 6A-1. Adjust the probe
heater to a temperature sufficient to prevent condensation (see Note in
Section 6.1). Place crushed ice and water around the impingers and
bubblers. Mount the CO2 absorber outside the water bath in a
vertical flow position with the sample gas inlet at the bottom.
Flexible tubing (e.g., Tygon) may be used to connect the last
SO2 absorbing impinger to the moisture absorber and to
connect the moisture absorber to the CO2 absorber. A second,
smaller CO2 absorber containing Ascarite II may be added in-
line downstream of the primary CO2 absorber as a
breakthrough indicator. Ascarite II turns white when CO2 is
absorbed.
8.2 Sampling Train Leak-Check Procedure and Sample Collection.
Same as Method 6, Sections 8.2 and 8.3, respectively.
8.3 Sample Recovery.
8.3.1 Moisture Measurement. Disconnect the isopropanol bubbler,
the SO2 impingers, and the moisture absorber from the sample
train. Allow about 10 minutes for them to reach room temperature, clean
the outside of loose dirt and moisture, and weigh them simultaneously
in the same manner as in Section 8.1. Record this final weight
(mwf).
8.3.2 Peroxide Solution. Discard the contents of the isopropanol
bubbler and pour the contents of the midget impingers into a leak-free
polyethylene bottle for shipping. Rinse the two midget impingers and
connecting tubes with water, and add the washing to the same storage
container.
8.3.3 CO2 Absorber. Allow the CO2 absorber
to warm to room temperature (about 10 minutes), clean the outside of
loose dirt and moisture, and weigh to the nearest 0.1 g in the same
manner as in Section 8.1. Record this final weight (maf).
Discard used Ascarite II material.

9.0 Quality Control

Same as Method 6, Section 9.0.

10.0 Calibration and Standardization

Same as Method 6, Section 10.0.

11.0 Analytical Procedure

11.1 Sample Analysis. The sample analysis procedure for
SO2 is the same as that specified in Method 6, Section 11.0.
11.2 Quality Assurance (QA) Audit Samples. Analysis of QA audit
samples is required only when this method is used for compliance
determinations. Obtain an audit sample set as directed in Section 7.3.6
of Method 6. Analyze the audit samples, and report the results as
directed in Section 11.3 of Method 6. Acceptance criteria for the audit
results are the same as those in Method 6.

12.0 Data Analysis and Calculations

Same as Method 6, Section 12.0, with the addition of the following:
12.1 Nomenclature.

Cw = Concentration of moisture, percent.
CCO2 = Concentration of CO2, dry basis, percent.
ESO2 = Emission rate of SO2, ng/J (lb/
106 Btu).
FC = Carbon F-factor from Method 19 for the fuel burned,
dscm/J (dscf/106 Btu).
mwi = Initial weight of impingers, bubblers, and moisture
absorber, g.
mwf = Final weight of impingers, bubblers, and moisture
absorber, g.
mai = Initial weight of CO2 absorber, g.
maf = Final weight of CO2 absorber, g.
mSO2 = Mass of SO2 collected, mg.
VCO2(std) = Equivalent volume of CO2 collected at
standard conditions, dscm (dscf).
Vw(std) = Equivalent volume of moisture collected at
standard conditions, scm (scf).

12.2 CO2 Volume Collected, Corrected to Standard
Conditions.
[GRAPHIC] [TIFF OMITTED] TR17OC00.192

Where:

K3 = Equivalent volume of gaseous CO2 at standard
conditions, 5.467 x 10-\4\ dscm/g (1.930 x
10-\2\ dscf/g).

12.3 Moisture Volume Collected, Corrected to Standard Conditions.
[GRAPHIC] [TIFF OMITTED] TR17OC00.193

Where:

K4 = Equivalent volume of water vapor at standard
conditions, 1.336 x 10-\3\ scm/g (4.717 x
10-\2\ scf/g).

12.4 SO2 Concentration.
[GRAPHIC] [TIFF OMITTED] TR17OC00.194

Where:

K2 = 32.03 mg SO2/meq. SO2 (7.061 x
10-\5\ lb SO2/meq. SO2)

12.5 CO2 Concentration.
[GRAPHIC] [TIFF OMITTED] TR17OC00.195

12.6 Moisture Concentration.
[GRAPHIC] [TIFF OMITTED] TR17OC00.196

13.0 Method Performance

13.1 Range and Precision. The minimum detectable limit and the
upper limit for the measurement of SO2 are the same as for
Method 6. For a 20-liter sample, this method has a precision of
0.5 percent CO2 for concentrations between 2.5
and 25 percent CO2 and 1.0 percent moisture for
moisture concentrations greater than 5 percent.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management. [Reserved]

16.0 Alternative Methods

If the only emission measurement desired is in terms of emission
rate of SO2 (ng/J or lb/10\6\ Btu), an abbreviated

[[Page 61898]]

procedure may be used. The differences between the above procedure and
the abbreviated procedure are described below.
16.1 Sampling Train. The sampling train is the same as that shown
in Figure 6A-1 and as described in Section 6.1, except that the dry gas
meter is not needed.
16.2 Preparation of the Sampling Train. Follow the same procedure
as in Section 8.1, except do not weigh the isopropanol bubbler, the
SO2 absorbing impingers, or the moisture absorber.
16.3 Sampling Train Leak-Check Procedure and Sample Collection.
Leak-check and operate the sampling train as described in Section 8.2,
except that dry gas meter readings, barometric pressure, and dry gas
meter temperatures need not be recorded during sampling.
16.4 Sample Recovery. Follow the procedure in Section 8.3, except
do not weigh the isopropanol bubbler, the SO2 absorbing
impingers, or the moisture absorber.
16.5 Sample Analysis. Analysis of the peroxide solution and QA
audit samples is the same as that described in Sections 11.1 and 11.2,
respectively.
16.6 Calculations.
16.6.1 SO2 Collected.
[GRAPHIC] [TIFF OMITTED] TR17OC00.197

Where:

K2 = 32.03 mg SO2/meq. SO2
K2 = 7.061 x 10-\5\ lb SO2/meq.
SO2

16.6.2 Sulfur Dioxide Emission Rate.
[GRAPHIC] [TIFF OMITTED] TR17OC00.198

Where:

K5 = 1.829 x 10\9\ mg/dscm
K2 = 0.1142 lb/dscf

17.0 References

Same as Method 6, Section 17.0, References 1 through 8, with the
addition of the following:

1. Stanley, Jon and P.R. Westlin. An Alternate Method for Stack
Gas Moisture Determination. Source Evaluation Society Newsletter.
3(4). November 1978.
2. Whittle, Richard N. and P.R. Westlin. Air Pollution Test
Report: Development and Evaluation of an Intermittent Integrated
SO2/CO2 Emission Sampling Procedure.
Environmental Protection Agency, Emission Standard and Engineering
Division, Emission Measurement Branch. Research Triangle Park, NC.
December 1979. 14 pp.
BILLING CODE 6560-50-P

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18.0 Tables, Diagrams, Flowcharts, and Validation Data
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BILLING CODE 6560-50-C

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Method 6B--Determination of Sulfur Dioxide and Carbon Dioxide Daily
Average Emissions From Fossil Fuel Combustion Sources

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Sulfur dioxide (SO2).............. 7449-09-05 3.4 mg SO2/m\3\
(2.12 x 10-\7\ lb/
ft\3\)
Carbon dioxide (CO2).............. 124-38-9 N/A
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of SO2 emissions from combustion sources in terms of
concentration (ng/dscm or lb/dscf) and emission rate (ng/J or lb/10\6\
Btu), and for the determination of CO2 concentration
(percent) on a daily (24 hours) basis.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 A gas sample is extracted from the sampling point in the stack
intermittently over a 24-hour or other specified time period. The
SO2 fraction is measured by the barium-thorin titration
method. Moisture and CO2 fractions are collected in the same
sampling train, and are determined gravimetrically.

3.0 Definitions. [Reserved]

4.0 Interferences

Same as Method 6, Section 4.0.

5.0 Safety

6.0 Equipment and Supplies

Same as Method 6A, Section 6.0, with the following exceptions and
additions:
6.1 The isopropanol bubbler is not used. An empty bubbler for the
collection of liquid droplets, that does not allow direct contact
between the collected liquid and the gas sample, may be included in the
sampling train.
6.2 For intermittent operation, include an industrial timer-switch
designed to operate in the ``on'' position at least 2 minutes
continuously and ``off'' the remaining period over a repeating cycle.
The cycle of operation is designated in the applicable regulation. At a
minimum, the sampling operation should include at least 12, equal,
evenly-spaced periods per 24 hours.
6.3 Stainless steel sampling probes, type 316, are not recommended
for use with Method 6B because of potential sample contamination due to
corrosion. Glass probes or other types of stainless steel, e.g.,
Hasteloy or Carpenter 20, are recommended for long-term use.

Note: For applications downstream of wet scrubbers, a heated
out-of-stack filter (either borosilicate glass wool or glass fiber
mat) is necessary. Probe and filter heating systems capable of
maintaining a sample gas temperature of between 20 and 120 deg.C
(68 and 248 deg.F) at the filter are also required in these cases.
The electric supply for these heating systems should be continuous
and separate from the timed operation of the sample pump.

7.0 Reagents and Standards

Same as Method 6A, Section 7.0, with the following exceptions:
7.1 Isopropanol is not used for sampling.
7.2 The hydrogen peroxide absorbing solution shall be diluted to
no less than 6 percent by volume, instead of 3 percent as specified in
Methods 6 and 6A.
7.3 If the Method 6B sampling train is to be operated in a low
sample flow condition (less than 100 ml/min or 0.21 ft\3\/hr),
molecular sieve material may be substituted for Ascarite II as the
CO2 absorbing material. The recommended molecular sieve
material is Union Carbide \1/16\ inch pellets, 5 A deg., or equivalent.
Molecular sieve material need not be discarded following the sampling
run, provided that it is regenerated as per the manufacturer's
instruction. Use of molecular sieve material at flow rates higher than
100 ml/min (0.21 ft\3\/hr) may cause erroneous CO2 results.

8.0 Sample Collection, Preservation, Transport, and Storage

8.1 Preparation of Sampling Train. Same as Method 6A, Section 8.1,
with the addition of the following:
8.1.1 The sampling train is assembled as shown in Figure 6A-1 of
Method 6A, except that the isopropanol bubbler is not included.
8.1.2 Adjust the timer-switch to operate in the ``on'' position
from 2 to 4 minutes on a 2-hour repeating cycle or other cycle
specified in the applicable regulation. Other timer sequences may be
used with the restriction that the total sample volume collected is
between 25 and 60 liters (0.9 and 2.1 ft 3) for the amounts
of sampling reagents prescribed in this method.
8.1.3 Add cold water to the tank until the impingers and bubblers
are covered at least two-thirds of their length. The impingers and
bubbler tank must be covered and protected from intense heat and direct
sunlight. If freezing conditions exist, the impinger solution and the
water bath must be protected.

Note: Sampling may be conducted continuously if a low flow-rate
sample pump [20 to 40 ml/min (0.04 to 0.08 ft3/hr) for
the reagent volumes described in this method] is used. If sampling
is continuous, the timer-switch is not necessary. In addition, if
the sample pump is designed for constant rate sampling, the rate
meter may be deleted. The total gas volume collected should be
between 25 and 60 liters (0.9 and 2.1 ft3) for the
amounts of sampling reagents prescribed in this method.

8.2 Sampling Train Leak-Check Procedure. Same as Method 6, Section
8.2.
8.3 Sample Collection.
8.3.1 The probe and filter (either in-stack, out-of-stack, or
both) must be heated to a temperature sufficient to prevent water
condensation.
8.3.2 Record the initial dry gas meter reading. To begin sampling,
position the tip of the probe at the sampling point, connect the probe
to the first impinger (or filter), and start the timer and the sample
pump. Adjust the sample flow to

[[Page 61902]]

a constant rate of approximately 1.0 liter/min (0.035 cfm) as indicated
by the rotameter. Observe the operation of the timer, and determine
that it is operating as intended (i.e., the timer is in the ``on''
position for the desired period, and the cycle repeats as required).
8.3.3 One time between 9 a.m. and 11 a.m. during the 24-hour
sampling period, record the dry gas meter temperature (Tm)
and the barometric pressure (P(bar)).
8.3.4 At the conclusion of the run, turn off the timer and the
sample pump, remove the probe from the stack, and record the final gas
meter volume reading. Conduct a leak-check as described in Section 8.2.
If a leak is found, void the test run or use procedures acceptable to
the Administrator to adjust the sample volume for leakage. Repeat the
steps in Sections 8.3.1 to 8.3.4 for successive runs.
8.4 Sample Recovery. The procedures for sample recovery (moisture
measurement, peroxide solution, and CO2 absorber) are the
same as those in Method 6A, Section 8.3.

9.0 Quality Control

Same as Method 6, Section 9.0., with the exception of the
isopropanol-check.

10.0 Calibration and Standardization

Same as Method 6, Section 10.0, with the addition of the following:
10.1 Periodic Calibration Check. After 30 days of operation of the
test train, conduct a calibration check according to the same
procedures as the post-test calibration check (Method 6, Section
10.1.2). If the deviation between initial and periodic calibration
factors exceeds 5 percent, use the smaller of the two factors in
calculations for the preceding 30 days of data, but use the most recent
calibration factor for succeeding test runs.

11.0 Analytical Procedures

11.1 Sample Loss Check and Analysis. Same as Method 6, Sections
11.1 and 11.2, respectively.
11.2 Quality Assurance (QA) Audit Samples. Analysis of QA audit
samples is required only when this method is used for compliance
determinations. Obtain an audit sample set as directed in Section 7.3.6
of Method 6. Analyze the audit samples at least once for every 30 days
of sample collection, and report the results as directed in Section
11.3 of Method 6. The analyst performing the sample analyses shall
perform the audit analyses. If more than one analyst performs the
sample analyses during the 30-day sampling period, each analyst shall
perform the audit analyses and all audit results shall be reported.
Acceptance criteria for the audit results are the same as those in
Method 6.

12.0 Data Analysis and Calculations

Same as Method 6A, Section 12.0, except that Pbar and
Tm correspond to the values recorded in Section 8.3.3 of
this method. The values are as follows:

Pbar = Initial barometric pressure for the test period, mm
Hg.
Tm = Absolute meter temperature for the test period, deg.K.

13.0 Method Performance

13.1 Range.
13.1.1 Sulfur Dioxide. Same as Method 6.
13.1.2 Carbon Dioxide. Not determined.
13.2 Repeatability and Reproducibility. EPA-sponsored
collaborative studies were undertaken to determine the magnitude of
repeatability and reproducibility achievable by qualified testers
following the procedures in this method. The results of the studies
evolve from 145 field tests including comparisons with Methods 3 and 6.
For measurements of emission rates from wet, flue gas desulfurization
units in (ng/J), the repeatability (intra-laboratory precision) is 8.0
percent and the reproducibility (inter-laboratory precision) is 11.1
percent.

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 Alternative Methods

Same as Method 6A, Section 16.0, except that the timer is needed
and is operated as outlined in this method.

17.0 References

Same as Method 6A, Section 17.0, with the addition of the
following:

1. Butler, Frank E., et. al. The Collaborative Test of Method
6B: Twenty-Four-Hour Analysis of SO2 and CO2.
JAPCA. Vol. 33, No. 10. October 1983.

18.0 Tables, Diagrams, Flowcharts, and Validation Data. [Reserved]

* * * * *

Method 7--Determination of Nitrogen Oxide Emissions From Stationary
Sources

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Nitrogen oxides (NOX), as NO2,
including:
Nitric oxide (NO)............. 10102-43-9
Nitrogen dioxide (NO2)........ 10102-44-0 2-400 mg/dscm
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the measurement
of nitrogen oxides (NOX) emitted from stationary sources.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sample methods.

2.0 Summary of Method

A grab sample is collected in an evacuated flask containing a
dilute sulfuric acid-hydrogen peroxide absorbing solution, and the
nitrogen oxides, except nitrous oxide, are measured colorimetrically
using the phenoldisulfonic acid (PDS) procedure.

3.0 Definitions. [Reserved]

4.0 Interferences

Biased results have been observed when sampling under conditions of
high sulfur dioxide concentrations (above 2000 ppm).

5.0 Safety

[[Page 61903]]

Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water for at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burns as thermal
burns.
5.2.1 Hydrogen Peroxide (H2O2). Irritating
to eyes, skin, nose, and lungs.
5.2.2 Phenoldisulfonic Acid. Irritating to eyes and skin.
5.2.3 Sodium Hydroxide (NaOH). Causes severe damage to eyes and
skin. Inhalation causes irritation to nose, throat, and lungs. Reacts
exothermically with limited amounts of water.
5.2.4 Sulfuric Acid (H2SO4). Rapidly
destructive to body tissue. Will cause third degree burns. Eye damage
may result in blindness. Inhalation may be fatal from spasm of the
larynx, usually within 30 minutes. May cause lung tissue damage with
edema. 1 mg/m 3 for 8 hours will cause lung damage or, in
higher concentrations, death. Provide ventilation to limit inhalation.
Reacts violently with metals and organics.
5.2.5 Phenol. Poisonous and caustic. Do not handle with bare hands
as it is absorbed through the skin.

6.0 Equipment and Supplies

6.1 Sample Collection. A schematic of the sampling train used in
performing this method is shown in Figure 7-1. Other grab sampling
systems or equipment, capable of measuring sample volume to within 2.0
percent and collecting a sufficient sample volume to allow analytical
reproducibility to within 5 percent, will be considered acceptable
alternatives, subject to the approval of the Administrator. The
following items are required for sample collection:
6.1.1 Probe. Borosilicate glass tubing, sufficiently heated to
prevent water condensation and equipped with an in-stack or heated out-
of-stack filter to remove particulate matter (a plug of glass wool is
satisfactory for this purpose). Stainless steel or Teflon tubing may
also be used for the probe. Heating is not necessary if the probe
remains dry during the purging period.
6.1.2 Collection Flask. Two-liter borosilicate, round bottom
flask, with short neck and 24/40 standard taper opening, protected
against implosion or breakage.
6.1.3 Flask Valve. T-bore stopcock connected to a 24/40 standard
taper joint.
6.1.4 Temperature Gauge. Dial-type thermometer, or other
temperature gauge, capable of measuring 1 deg.C (2 deg.F) intervals
from -5 to 50 deg.C (23 to 122 deg.F).
6.1.5 Vacuum Line. Tubing capable of withstanding a vacuum of 75
mm (3 in.) Hg absolute pressure, with ``T'' connection and T-bore
stopcock.
6.1.6 Vacuum Gauge. U-tube manometer, 1 meter (39 in.), with 1 mm
(0.04 in.) divisions, or other gauge capable of measuring pressure to
within 2.5 mm (0.10 in.) Hg.
6.1.7 Pump. Capable of evacuating the collection flask to a
pressure equal to or less than 75 mm (3 in.) Hg absolute.
6.1.8 Squeeze Bulb. One-way.
6.1.9 Volumetric Pipette. 25-ml.
6.1.10 Stopcock and Ground Joint Grease. A high-vacuum, high-
temperature chlorofluorocarbon grease is required. Halocarbon 25-5S has
been found to be effective.
6.1.11 Barometer. Mercury, aneroid, or other barometer capable of
measuring atmospheric pressure to within 2.5 mm (0.1 in.) Hg. See NOTE
in Method 5, Section 6.1.2.
6.2 Sample Recovery. The following items are required for sample
recovery:
6.2.1 Graduated Cylinder. 50-ml with 1 ml divisions.
6.2.2 Storage Containers. Leak-free polyethylene bottles.
6.2.3 Wash Bottle. Polyethylene or glass.
6.2.4 Glass Stirring Rod.
6.2.5 Test Paper for Indicating pH. To cover the pH range of 7 to
14.
6.3 Analysis. The following items are required for analysis:
6.3.1 Volumetric Pipettes. Two 1-ml, two 2-ml, one 3-ml, one 4-ml,
two 10-ml, and one 25-ml for each sample and standard.
6.3.2 Porcelain Evaporating Dishes. 175- to 250-ml capacity with
lip for pouring, one for each sample and each standard. The Coors No.
45006 (shallowform, 195-ml) has been found to be satisfactory.
Alternatively, polymethyl pentene beakers (Nalge No. 1203, 150-ml), or
glass beakers (150-ml) may be used. When glass beakers are used,
etching of the beakers may cause solid matter to be present in the
analytical step; the solids should be removed by filtration.
6.3.3 Steam Bath. Low-temperature ovens or thermostatically
controlled hot plates kept below 70 deg.C (160 deg.F) are acceptable
alternatives.
6.3.4 Dropping Pipette or Dropper. Three required.
6.3.5 Polyethylene Policeman. One for each sample and each
standard.
6.3.6 Graduated Cylinder. 100-ml with 1-ml divisions.
6.3.7 Volumetric Flasks. 50-ml (one for each sample and each
standard), 100-ml (one for each sample and each standard, and one for
the working standard KNO3 solution), and 1000-ml (one).
6.3.8 Spectrophotometer. To measure at 410 nm.
6.3.9 Graduated Pipette. 10-ml with 0.1-ml divisions.
6.3.10 Test Paper for Indicating pH. To cover the pH range of 7 to
14.
6.3.11 Analytical Balance. To measure to within 0.1 mg.

7.0 Reagents and Standards

[[Page 61904]]

7.3.8 Phenoldisulfonic Acid Solution. Dissolve 25 g of pure white
phenol solid in 150 ml concentrated sulfuric acid on a steam bath.
Cool, add 75 ml fuming sulfuric acid (15 to 18 percent by weight free
sulfur trioxide--HANDLE WITH CAUTION), and heat at 100 deg.C (212
deg.F) for 2 hours. Store in a dark, stoppered bottle.
7.3.9 Concentrated Ammonium Hydroxide.
7.3.10 Quality Assurance Audit Samples. When making compliance
determinations, and upon availability, audit samples may be obtained
from the appropriate EPA Regional Office or from the responsible
enforcement authority.

Note: The responsible enforcement authority should be notified
at least 30 days prior to the test date to allow sufficient time for
sample delivery.

8.0 Sample Collection, Preservation, Storage and Transport

8.1 Sample Collection.
8.1.1 Flask Volume. The volume of the collection flask and flask
valve combination must be known prior to sampling. Assemble the flask
and flask valve, and fill with water to the stopcock. Measure the
volume of water to 10 ml. Record this volume on the flask.
8.1.2 Pipette 25 ml of absorbing solution into a sample flask,
retaining a sufficient quantity for use in preparing the calibration
standards. Insert the flask valve stopper into the flask with the valve
in the ``purge'' position. Assemble the sampling train as shown in
Figure 7-1, and place the probe at the sampling point. Make sure that
all fittings are tight and leak-free, and that all ground glass joints
have been greased properly with a high-vacuum, high temperature
chlorofluorocarbon-based stopcock grease. Turn the flask valve and the
pump valve to their ``evacuate'' positions. Evacuate the flask to 75 mm
(3 in.) Hg absolute pressure, or less. Evacuation to a pressure
approaching the vapor pressure of water at the existing temperature is
desirable. Turn the pump valve to its ``vent'' position, and turn off
the pump. Check for leakage by observing the manometer for any pressure
fluctuation. (Any variation greater than 10 mm (0.4 in.) Hg over a
period of 1 minute is not acceptable, and the flask is not to be used
until the leakage problem is corrected. Pressure in the flask is not to
exceed 75 mm (3 in.) Hg absolute at the time sampling is commenced.)
Record the volume of the flask and valve (Vf), the flask
temperature (Ti), and the barometric pressure. Turn the
flask valve counterclockwise to its ``purge'' position, and do the same
with the pump valve. Purge the probe and the vacuum tube using the
squeeze bulb. If condensation occurs in the probe and the flask valve
area, heat the probe, and purge until the condensation disappears.
Next, turn the pump valve to its ``vent'' position. Turn the flask
valve clockwise to its ``evacuate'' position, and record the difference
in the mercury levels in the manometer. The absolute internal pressure
in the flask (Pi) is equal to the barometric pressure less
the manometer reading. Immediately turn the flask valve to the
``sample'' position, and permit the gas to enter the flask until
pressures in the flask and sample line (i.e., duct, stack) are equal.
This will usually require about 15 seconds; a longer period indicates a
plug in the probe, which must be corrected before sampling is
continued. After collecting the sample, turn the flask valve to its
``purge'' position, and disconnect the flask from the sampling train.
8.1.3 Shake the flask for at least 5 minutes.
8.1.4 If the gas being sampled contains insufficient oxygen for
the conversion of NO to NO2 (e.g., an applicable subpart of
the standards may require taking a sample of a calibration gas mixture
of NO in N2), then introduce oxygen into the flask to permit
this conversion. Oxygen may be introduced into the flask by one of
three methods: (1) Before evacuating the sampling flask, flush with
pure cylinder oxygen, then evacuate flask to 75 mm (3 in.) Hg absolute
pressure or less; or (2) inject oxygen into the flask after sampling;
or (3) terminate sampling with a minimum of 50 mm (2 in.) Hg vacuum
remaining in the flask, record this final pressure, and then vent the
flask to the atmosphere until the flask pressure is almost equal to
atmospheric pressure.
8.2 Sample Recovery. Let the flask sit for a minimum of 16 hours,
and then shake the contents for 2 minutes.
8.2.1 Connect the flask to a mercury filled U-tube manometer. Open
the valve from the flask to the manometer, and record the flask
temperature (Tf), the barometric pressure, and the
difference between the mercury levels in the manometer. The absolute
internal pressure in the flask (Pf) is the barometric
pressure less the manometer reading. Transfer the contents of the flask
to a leak-free polyethylene bottle. Rinse the flask twice with 5 ml
portions of water, and add the rinse water to the bottle. Adjust the pH
to between 9 and 12 by adding 1 N NaOH, dropwise (about 25 to 35
drops). Check the pH by dipping a stirring rod into the solution and
then touching the rod to the pH test paper. Remove as little material
as possible during this step. Mark the height of the liquid level so
that the container can be checked for leakage after transport. Label
the container to identify clearly its contents. Seal the container for
shipping.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
10.1.......................... Spectrophotometer Ensure linearity of
calibration. spectrophotometer
response to
standards.
11.4.......................... Audit sample Evaluate analytical
analysis. technique,
preparation of
standards.
------------------------------------------------------------------------

10.0 Calibration and Standardization

10.1 Spectrophotometer.
10.1.1 Optimum Wavelength Determination.
10.1.1.1 Calibrate the wavelength scale of the spectrophotometer
every 6 months. The calibration may be accomplished by using an energy
source with an intense line emission such as a mercury lamp, or by
using a series of glass filters spanning the measuring range of the
spectrophotometer. Calibration materials are available commercially and
from the National Institute of Standards and Technology. Specific
details on the use of such materials should be supplied by the vendor;
general information about calibration techniques can be obtained from
general reference books on analytical chemistry. The wavelength scale
of the spectrophotometer must read correctly within 5 nm at all
calibration points; otherwise, repair and recalibrate the
spectrophotometer. Once the wavelength scale of the spectrophotometer
is in proper calibration, use 410 nm as the optimum wavelength for the
measurement of the absorbance of the standards and samples.
10.1.1.2 Alternatively, a scanning procedure may be employed to
determine the proper measuring wavelength. If the instrument is a
double-beam spectrophotometer, scan the spectrum between 400 and 415 nm

[[Page 61905]]

using a 200 g NO2 standard solution in the sample
cell and a blank solution in the reference cell. If a peak does not
occur, the spectrophotometer is probably malfunctioning and should be
repaired. When a peak is obtained within the 400 to 415 nm range, the
wavelength at which this peak occurs shall be the optimum wavelength
for the measurement of absorbance of both the standards and the
samples. For a single-beam spectrophotometer, follow the scanning
procedure described above, except scan separately the blank and
standard solutions. The optimum wavelength shall be the wavelength at
which the maximum difference in absorbance between the standard and the
blank occurs.
10.1.2 Determination of Spectrophotometer Calibration Factor
Kc. Add 0 ml, 2.0 ml, 4.0 ml, 6.0 ml, and 8.0 ml of the
KNO3 working standard solution (1 ml = 100 g
NO2) to a series of five 50-ml volumetric flasks. To each
flask, add 25 ml of absorbing solution and 10 ml water. Add 1 N NaOH to
each flask until the pH is between 9 and 12 (about 25 to 35 drops).
Dilute to the mark with water. Mix thoroughly, and pipette a 25-ml
aliquot of each solution into a separate porcelain evaporating dish.
Beginning with the evaporation step, follow the analysis procedure of
Section 11.2 until the solution has been transferred to the 100-ml
volumetric flask and diluted to the mark. Measure the absorbance of
each solution at the optimum wavelength as determined in Section
10.2.1. This calibration procedure must be repeated on each day that
samples are analyzed. Calculate the spectrophotometer calibration
factor as shown in Section 12.2.
10.1.3 Spectrophotometer Calibration Quality Control. Multiply the
absorbance value obtained for each standard by the Kc factor
(reciprocal of the least squares slope) to determine the distance each
calibration point lies from the theoretical calibration line. The
difference between the calculated concentration values and the actual
concentrations (i.e., 100, 200, 300, and 400 g NO2)
should be less than 7 percent for all standards.
10.2 Barometer. Calibrate against a mercury barometer.
10.3 Temperature Gauge. Calibrate dial thermometers against
mercury-in-glass thermometers.
10.4 Vacuum Gauge. Calibrate mechanical gauges, if used, against a
mercury manometer such as that specified in Section 6.1.6.
10.5 Analytical Balance. Calibrate against standard weights.

11.0 Analytical Procedures

11.1 Sample Loss Check. Note the level of the liquid in the
container, and confirm whether any sample was lost during shipment.
Note this on the analytical data sheet. If a noticeable amount of
leakage has occurred, either void the sample or use methods, subject to
the approval of the Administrator, to correct the final results.
11.2 Sample Preparation. Immediately prior to analysis, transfer
the contents of the shipping container to a 50 ml volumetric flask, and
rinse the container twice with 5 ml portions of water. Add the rinse
water to the flask, and dilute to mark with water; mix thoroughly.
Pipette a 25-ml aliquot into the porcelain evaporating dish. Return any
unused portion of the sample to the polyethylene storage bottle.
Evaporate the 25-ml aliquot to dryness on a steam bath, and allow to
cool. Add 2 ml phenoldisulfonic acid solution to the dried residue, and
triturate thoroughly with a polyethylene policeman. Make sure the
solution contacts all the residue. Add 1 ml water and 4 drops of
concentrated sulfuric acid. Heat the solution on a steam bath for 3
minutes with occasional stirring. Allow the solution to cool, add 20 ml
water, mix well by stirring, and add concentrated ammonium hydroxide,
dropwise, with constant stirring, until the pH is 10 (as determined by
pH paper). If the sample contains solids, these must be removed by
filtration (centrifugation is an acceptable alternative, subject to the
approval of the Administrator) as follows: Filter through Whatman No.
41 filter paper into a 100-ml volumetric flask. Rinse the evaporating
dish with three 5-ml portions of water. Filter these three rinses. Wash
the filter with at least three 15-ml portions of water. Add the filter
washings to the contents of the volumetric flask, and dilute to the
mark with water. If solids are absent, the solution can be transferred
directly to the 100-ml volumetric flask and diluted to the mark with
water.
11.3 Sample Analysis. Mix the contents of the flask thoroughly,
and measure the absorbance at the optimum wavelength used for the
standards (Section 10.2.1), using the blank solution as a zero
reference. Dilute the sample and the blank with equal volumes of water
if the absorbance exceeds A4, the absorbance of the 400-
g NO2 standard (see Section 10.2.2).
11.4 Audit Sample Analysis.
11.4.1 When the method is used to analyze samples to demonstrate
compliance with a source emission regulation, an audit sample must be
analyzed, subject to availability.
11.4.2 Concurrently analyze the audit sample and the compliance
samples in the same manner to evaluate the technique of the analyst and
the standards preparation.
11.4.3 The same analyst, analytical reagents, and analytical
system must be used for the compliance samples and the audit sample. If
this condition is met, duplicate auditing of subsequent compliance
analyses for the same enforcement agency within a 30-day period is
waived. An audit sample set may not be used to validate different sets
of compliance samples under the jurisdiction of separate enforcement
agencies, unless prior arrangements have been made with both
enforcement agencies.
11.5 Audit Sample Results.
11.5.1 Calculate the audit sample concentrations and submit
results using the instructions provided with the audit samples.
11.5.2 Report the results of the audit samples and the compliance
determination samples along with their identification numbers, and the
analyst's name to the responsible enforcement authority. Include this
information with reports of any subsequent compliance analyses for the
same enforcement authority during the 30-day period.
11.5.3 The concentrations of the audit samples obtained by the
analyst must agree within 5 percent of the actual concentration. If the
5 percent specification is not met, reanalyze the compliance and audit
samples, and include initial and reanalysis values in the test report.
11.5.4 Failure to meet the 5-percent specification may require
retests until the audit problems are resolved. However, if the audit
results do not affect the compliance or noncompliance status of the
affected facility, the Administrator may waive the reanalysis
requirement, further audits, or retests and accept the results of the
compliance test. While steps are being taken to resolve audit analysis
problems, the Administrator may also choose to use the data to
determine the compliance or noncompliance status of the affected
facility.

12.0 Data Analysis and Calculations

Carry out the calculations, retaining at least one extra
significant figure beyond that of the acquired data. Round off figures
after final calculations.
12.1 Nomenclature.

A = Absorbance of sample.
A1 = Absorbance of the 100-g NO2
standard.
A2 = Absorbance of the 200-g NO2
standard.

[[Page 61906]]

A3 = Absorbance of the 300-g NO2
standard.
A4 = Absorbance of the 400-g NO2
standard.
C = Concentration of NOX as NO2, dry basis,
corrected to standard conditions, mg/dsm\3\ (lb/dscf).
Cd = Determined audit sample concentration, mg/dscm.
Ca = Actual audit sample concentration, mg/dscm.
F = Dilution factor (i.e., 25/5, 25/10, etc., required only if sample
dilution was needed to reduce the absorbance into the range of the
calibration).
Kc = Spectrophotometer calibration factor.
m = Mass of NOX as NO2 in gas sample, g.
Pf = Final absolute pressure of flask, mm Hg (in. Hg).
Pi = Initial absolute pressure of flask, mm Hg (in. Hg).
Pstd = Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
RE = Relative error for QA audit samples, percent.
Tf = Final absolute temperature of flask, deg.K ( deg.R).
Ti = Initial absolute temperature of flask, deg.K ( deg.R).
Tstd = Standard absolute temperature, 293 deg.K (528
deg.R).
Vsc = Sample volume at standard conditions (dry basis), ml.
Vf = Volume of flask and valve, ml.
Va = Volume of absorbing solution, 25 ml.

12.2 Spectrophotometer Calibration Factor.
[GRAPHIC] [TIFF OMITTED] TR17OC00.200

12.3 Sample Volume, Dry Basis, Corrected to Standard Conditions.
[GRAPHIC] [TIFF OMITTED] TR17OC00.201

Where:

K1 = 0.3858 deg.K/mm Hg for metric units,
K1 = 17.65 deg.R/in. Hg for English units.

12.4 Total g NO2 per sample.
[GRAPHIC] [TIFF OMITTED] TR17OC00.202

Where:
2 = 50/25, the aliquot factor.

Note: If other than a 25-ml aliquot is used for analysis, the
factor 2 must be replaced by a corresponding factor.

12.5 Sample Concentration, Dry Basis, Corrected to Standard
Conditions.
[GRAPHIC] [TIFF OMITTED] TR17OC00.203

Where:
K2 = 10\3\ (mg/m\3\)/(g/ml) for metric units,
K2 = 6.242 x 10-\5\ (lb/scf)/(g/ml)
for English units.
12.6 Relative Error for QA Audit Samples.
[GRAPHIC] [TIFF OMITTED] TR17OC00.204

13.0 Method Performance

13.1 Range. The analytical range of the method has been determined
to be 2 to 400 milligrams NOX (as NO2) per dry
standard cubic meter, without having to dilute the sample.

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

1. Standard Methods of Chemical Analysis. 6th ed. New York, D.
Van Nostrand Co., Inc. 1962. Vol. 1, pp. 329-330.
2. Standard Method of Test for Oxides of Nitrogen in Gaseous
Combustion Products (Phenoldisulfonic Acid Procedure). In: 1968 Book
of ASTM Standards, Part 26. Philadelphia, PA. 1968. ASTM Designation
D 1608-60, pp. 725-729.
3. Jacob, M.B. The Chemical Analysis of Air Pollutants. New
York. Interscience Publishers, Inc. 1960. Vol. 10, pp. 351-356.
4. Beatty, R.L., L.B. Berger, and H.H. Schrenk. Determination of
Oxides of Nitrogen by the Phenoldisulfonic Acid Method. Bureau of
Mines, U.S. Dept. of Interior. R.I. 3687. February 1943.
5. Hamil, H.F. and D.E. Camann. Collaborative Study of Method
for the Determination of Nitrogen Oxide Emissions from Stationary
Sources (Fossil Fuel-Fired Steam Generators). Southwest Research
Institute Report for Environmental Protection Agency. Research
Triangle Park, NC. October 5, 1973.
6. Hamil, H.F. and R.E. Thomas. Collaborative Study of Method
for the Determination of Nitrogen Oxide Emissions from Stationary
Sources (Nitric Acid Plants). Southwest Research Institute Report
for Environmental Protection Agency. Research Triangle Park, NC. May
8, 1974.
7. Stack Sampling Safety Manual (Draft). U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC. September 1978.
BILLING CODE 6560-50-P

[[Page 61907]]

17.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR17OC00.205

BILLING CODE 6560-50-C

[[Page 61908]]

Method 7A--Determination of Nitrogen Oxide Emissions From
Stationary Sources (Ion Chromatographic Method)

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Nitrogen oxides (NOX), as NO2,
including:
Nitric oxide (NO)............. 10102-43-9 ....................
Nitrogen dioxide (NO2)........ 10102-44-0 65-655 ppmv
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of NOX emissions from stationary sources.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

A grab sample is collected in an evacuated flask containing a
dilute sulfuric acid-hydrogen peroxide absorbing solution. The nitrogen
oxides, excluding nitrous oxide (N2O), are oxidized to
nitrate and measured by ion chromatography.

3.0 Definitions [Reserved]

4.0 Interferences

Biased results have been observed when sampling under conditions of
high sulfur dioxide concentrations (above 2000 ppm).

5.0 Safety

5.1 This method may involve hazardous materials, operations, and
equipment. This test method may not address all of the safety problems
associated with its use. It is the responsibility of the user of this
test method to establish appropriate safety and health practices and to
determine the applicability of regulatory limitations prior to
performing this test method.
5.2 Corrosive reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burns as thermal
burns.
5.2.1 Hydrogen Peroxide (H2O2). Irritating
to eyes, skin, nose, and lungs.
5.2.2 Sulfuric Acid (H2SO4). Rapidly
destructive to body tissue. Will cause third degree burns. Eye damage
may result in blindness. Inhalation may be fatal from spasm of the
larynx, usually within 30 minutes. May cause lung tissue damage with
edema. 3 mg/m3 will cause lung damage in uninitiated. 1 mg/
m3 for 8 hours will cause lung damage or, in higher
concentrations, death. Provide ventilation to limit inhalation. Reacts
violently with metals and organics.

6.0 Equipment and Supplies

6.1 Sample Collection. Same as in Method 7, Section 6.1.
6.2 Sample Recovery. Same as in Method 7, Section 6.2, except the
stirring rod and pH paper are not needed.
6.3 Analysis. For the analysis, the following equipment and
supplies are required. Alternative instrumentation and procedures will
be allowed provided the calibration precision requirement in Section
10.1.2 and audit accuracy requirement in Section 11.3 can be met.
6.3.1 Volumetric Pipets. Class A;
1-, 2-, 4-, 5-ml (two for the set of standards and one per sample), 6-,
10-, and graduated 5-ml sizes.
6.3.2 Volumetric Flasks. 50-ml (two per sample and one per
standard), 200-ml, and 1-liter sizes.
6.3.3 Analytical Balance. To measure to within 0.1 mg.
6.3.4 Ion Chromatograph. The ion chromatograph should have at
least the following components:
6.3.4.1 Columns. An anion separation or other column capable of
resolving the nitrate ion from sulfate and other species present and a
standard anion suppressor column (optional). Suppressor columns are
produced as proprietary items; however, one can be produced in the
laboratory using the resin available from BioRad Company, 32nd and
Griffin Streets, Richmond, California. Peak resolution can be optimized
by varying the eluent strength or column flow rate, or by experimenting
with alternative columns that may offer more efficient separation. When
using guard columns with the stronger reagent to protect the separation
column, the analyst should allow rest periods between injection
intervals to purge possible sulfate buildup in the guard column.
6.3.4.2 Pump. Capable of maintaining a steady flow as required by
the system.
6.3.4.3 Flow Gauges. Capable of measuring the specified system
flow rate.
6.3.4.4 Conductivity Detector.
6.3.4.5 Recorder. Compatible with the output voltage range of the
detector.

7.0 Reagents and Standards

[[Page 61909]]

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Sampling. Same as in Method 7, Section 8.1.
8.2 Sample Recovery. Same as in Method 7, Section 8.2, except
delete the steps on adjusting and checking the pH of the sample. Do not
store the samples more than 4 days between collection and analysis.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
10.1.......................... Ion chromatograph Ensure linearity of
calibration. ion chromatograph
response to
standards.
11.3.......................... Audit sample Evaluate analytical
analysis. technique,
preparation of
standards.
------------------------------------------------------------------------

10.0 Calibration and Standardizations

10.1 Ion Chromatograph.
10.1.1 Determination of Ion Chromatograph Calibration Factor S.
Prepare a series of five standards by adding 1.0, 2.0, 4.0, 6.0, and
10.0 ml of working standard solution (25 g/ml) to a series of
five 50-ml volumetric flasks. (The standard masses will equal 25, 50,
100, 150, and 250 g.) Dilute each flask to the mark with
water, and mix well. Analyze with the samples as described in Section
11.2, and subtract the blank from each value. Prepare or calculate a
linear regression plot of the standard masses in g (x-axis)
versus their peak height responses in millimeters (y-axis). (Take peak
height measurements with symmetrical peaks; in all other cases,
calculate peak areas.) From this curve, or equation, determine the
slope, and calculate its reciprocal to denote as the calibration
factor, S.
10.1.2 Ion Chromatograph Calibration Quality Control. If any point
on the calibration curve deviates from the line by more than 7 percent
of the concentration at that point, remake and reanalyze that standard.
This deviation can be determined by multiplying S times the peak height
response for each standard. The resultant concentrations must not
differ by more than 7 percent from each known standard mass (i.e., 25,
50, 100, 150, and 250 g).
10.2 Conductivity Detector. Calibrate according to manufacturer's
specifications prior to initial use.
10.3 Barometer. Calibrate against a mercury barometer.
10.4 Temperature Gauge. Calibrate dial thermometers against
mercury-in-glass thermometers.
10.5 Vacuum Gauge. Calibrate mechanical gauges, if used, against a
mercury manometer such as that specified in Section 6.1.6 of Method 7.
10.6 Analytical Balance. Calibrate against standard weights.

11.0 Analytical Procedures

11.1 Sample Preparation.
11.1.1 Note on the analytical data sheet, the level of the liquid
in the container, and whether any sample was lost during shipment. If a
noticeable amount of leakage has occurred, either void the sample or
use methods, subject to the approval of the Administrator, to correct
the final results. Immediately before analysis, transfer the contents
of the shipping container to a 50-ml volumetric flask, and rinse the
container twice with 5 ml portions of water. Add the rinse water to the
flask, and dilute to the mark with water. Mix thoroughly.
11.1.2 Pipet a 5-ml aliquot of the sample into a 50-ml volumetric
flask, and dilute to the mark with water. Mix thoroughly. For each set
of determinations, prepare a reagent blank by diluting 5 ml of
absorbing solution to 50 ml with water. (Alternatively, eluent solution
may be used instead of water in all sample, standard, and blank
dilutions.)
11.2 Analysis.
11.2.1 Prepare a standard calibration curve according to Section
10.1.1. Analyze the set of standards followed by the set of samples
using the same injection volume for both standards and samples. Repeat
this analysis sequence followed by a final analysis of the standard
set. Average the results. The two sample values must agree within 5
percent of their mean for the analysis to be valid. Perform this
duplicate analysis sequence on the same day. Dilute any sample and the
blank with equal volumes of water if the concentration exceeds that of
the highest standard.
11.2.2 Document each sample chromatogram by listing the following
analytical parameters: injection point, injection volume, nitrate and
sulfate retention times, flow rate, detector sensitivity setting, and
recorder chart speed.
11.3 Audit Sample Analysis. Same as Method 7, Section 11.4.

12.0 Data Analysis and Calculations

Carry out the calculations, retaining at least one extra
significant figure beyond that of the acquired data. Round off figures
after final calculations.
12.1 Sample Volume. Calculate the sample volume Vsc (in ml), on a
dry basis, corrected to standard conditions, using Equation 7-2 of
Method 7.
12.2 Sample Concentration of NOX as NO2.
12.2.1 Calculate the sample concentration C (in mg/dscm) as
follows:
[GRAPHIC] [TIFF OMITTED] TR17OC00.206

Where:

H = Sample peak height, mm.
S = Calibration factor, g/mm.
F = Dilution factor (required only if sample dilution was needed to
reduce the concentration into the range of calibration), dimensionless.
104 = 1:10 dilution times conversion factor of: (mg/10\3\
g)(10\6\ ml/m\3\).

12.2.2 If desired, the concentration of NO2 may be
calculated as ppm NO2 at standard conditions as follows:
[GRAPHIC] [TIFF OMITTED] TR17OC00.207

Where:

0.5228 = ml/mg NO2.

13.0 Method Performance

13.1 Range. The analytical range of the method is from 125 to 1250
mg NOX/m3 as NO2 (65 to 655 ppmv), and
higher concentrations may be analyzed by diluting the sample. The lower
detection limit is approximately 19 mg/m\3\ (10 ppmv), but may vary
among instruments.

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

1. Mulik, J.D., and E. Sawicki. Ion Chromatographic Analysis of
Environmental Pollutants. Ann Arbor, Ann Arbor Science Publishers,
Inc. Vol. 2, 1979.
2. Sawicki, E., J.D. Mulik, and E. Wittgenstein. Ion
Chromatographic Analysis of Environmental Pollutants. Ann Arbor, Ann
Arbor Science Publishers, Inc. Vol. 1. 1978.
3. Siemer, D.D. Separation of Chloride and Bromide from Complex
Matrices Prior to Ion Chromatographic Determination. Anal. Chem.
52(12):1874-1877. October 1980.
4. Small, H., T.S. Stevens, and W.C. Bauman. Novel Ion Exchange
Chromatographic Method Using Conductimetric Determination. Anal.
Chem. 47(11):1801. 1975.

[[Page 61910]]

5. Yu, K.K., and P.R. Westlin. Evaluation of Reference Method 7
Flask Reaction Time. Source Evaluation Society Newsletter. 4(4).
November 1979. 10 pp.
6. Stack Sampling Safety Manual (Draft). U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standard,
Research Triangle Park, NC. September 1978.

17.0 Tables, Diagrams, Flowcharts, and Validation Data. [Reserved]

Method 7B--Determination of Nitrogen Oxide Emissions From
Stationary Sources (Ultraviolet Spectrophotometric Method)

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Nitrogen oxides (NOX), as NO2,
including:
Nitric oxide (NO)............. 10102-43-9
Nitrogen dioxide (NO2)........ 10102-44-0 30-786 ppmv
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of NOX emissions from nitric acid plants.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 A grab sample is collected in an evacuated flask containing a
dilute sulfuric acid-hydrogen peroxide absorbing solution; the
NOX, excluding nitrous oxide (N2O), are measured
by ultraviolet spectrophotometry.

3.0 Definition. [Reserved]

4.0 Interferences. [Reserved]

5.0 Safety

5.1 This method may involve hazardous materials, operations, and
equipment. This test method may not address all of the safety problems
associated with its use. It is the responsibility of the user of this
test method to establish appropriate safety and health practices and to
determine the applicability of regulatory limitations prior to
performing this test method.
5.2 Corrosive reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burn as thermal burn.
5.2.1 Hydrogen Peroxide (H2O2). Irritating
to eyes, skin, nose, and lungs.
5.2.2 Sodium Hydroxide (NaOH). Causes severe damage to eyes and
skin. Inhalation causes irritation to nose, throat, and lungs. Reacts
exothermically with limited amounts of water.
5.2.3 Sulfuric Acid (H2SO4). Rapidly
destructive to body tissue. Will cause third degree burns. Eye damage
may result in blindness. Inhalation may be fatal from spasm of the
larynx, usually within 30 minutes. May cause lung tissue damage with
edema. 3 mg/m \3\ will cause lung damage in uninitiated. 1 mg/m \3\ for
8 hours will cause lung damage or, in higher concentrations, death.
Provide ventilation to limit inhalation. Reacts violently with metals
and organics.

6.0 Equipment and Supplies

6.1 Sample Collection. Same as Method 7, Section 6.1.
6.2 Sample Recovery. The following items are required for sample
recovery:
6.2.1 Wash Bottle. Polyethylene or glass.
6.2.2 Volumetric Flasks. 100-ml (one for each sample).
6.3 Analysis. The following items are required for analysis:
6.3.1 Volumetric Pipettes. 5-, 10-, 15-, and 20-ml to make
standards and sample dilutions.
6.3.2 Volumetric Flasks. 1000- and 100-ml for preparing standards
and dilution of samples.
6.3.3 Spectrophotometer. To measure ultraviolet absorbance at 210
nm.
6.3.4 Analytical Balance. To measure to within 0.1 mg.

7.0 Reagents and Standards

Note: Unless otherwise indicated, all reagents are to conform to
the specifications established by the Committee on Analytical
Reagents of the American Chemical Society, where such specifications
are available. Otherwise, use the best available grade.

7.1 Sample Collection. Same as Method 7, Section 7.1. It is
important that the amount of hydrogen peroxide in the absorbing
solution not be increased. Higher concentrations of peroxide may
interfere with sample analysis.
7.2 Sample Recovery. Same as Method 7, Section 7.2.
7.3 Analysis. Same as Method 7, Sections 7.3.1, 7.3.3, and 7.3.4,
with the addition of the following:
7.3.1 Working Standard KNO3 Solution. Dilute 10 ml of
the standard solution to 1000 ml with water. One milliliter of the
working standard is equivalent to 10 g NO2.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Sample Collection. Same as Method 7, Section 8.1.
8.2 Sample Recovery.
8.2.1 Let the flask sit for a minimum of 16 hours, and then shake
the contents for 2 minutes.
8.2.2 Connect the flask to a mercury filled U-tube manometer. Open
the valve from the flask to the manometer, and record the flask
temperature (Tf), the barometric pressure, and the
difference between the mercury levels in the manometer. The absolute
internal pressure in the flask (Pf) is the barometric
pressure less the manometer reading.
8.2.3 Transfer the contents of the flask to a leak-free wash
bottle. Rinse the flask three times with 10-ml portions of water, and
add to the bottle. Mark the height of the liquid level so that the
container can be checked for leakage after transport. Label the
container to identify clearly its contents. Seal the container for
shipping.

9.0 Quality Control

[[Page 61911]]

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
10.1.......................... Spectrophometer Ensures linearity of
calibration. spectrophotometer
response to
standards.
11.4.......................... Audit sample Evaluates analytical
analysis. technique and
preparation of
standards.
------------------------------------------------------------------------

10.0 Calibration and Standardizations

Same as Method 7, Sections 10.2 through 10.5, with the addition of
the following:
10.1 Determination of Spectrophotometer Standard Curve. Add 0 ml,
5 ml, 10 ml, 15 ml, and 20 ml of the KNO3 working standard
solution (1 ml = 10 g NO2) to a series of five 100-
ml volumetric flasks. To each flask, add 5 ml of absorbing solution.
Dilute to the mark with water. The resulting solutions contain 0.0, 50,
100, 150, and 200 g NO2, respectively. Measure the
absorbance by ultraviolet spectrophotometry at 210 nm, using the blank
as a zero reference. Prepare a standard curve plotting absorbance vs.
g NO2.

Note: If other than a 20-ml aliquot of sample is used for
analysis, then the amount of absorbing solution in the blank and
standards must be adjusted such that the same amount of absorbing
solution is in the blank and standards as is in the aliquot of
sample used.

10.1.1 Calculate the spectrophotometer calibration factor as
follows:
[GRAPHIC] [TIFF OMITTED] TR17OC00.208

Where:

Mi = Mass of NO2 in standard i, g.
Ai = Absorbance of NO2 standard i.
n = Total number of calibration standards.

10.1.2 For the set of calibration standards specified here,
Equation 7B-1 simplifies to the following:
[GRAPHIC] [TIFF OMITTED] TR17OC00.209

10.2 Spectrophotometer Calibration Quality Control. Multiply the
absorbance value obtained for each standard by the Kc factor
(reciprocal of the least squares slope) to determine the distance each
calibration point lies from the theoretical calibration line. The
difference between the calculated concentration values and the actual
concentrations (i.e., 50, 100, 150, and 200 g NO2)
should be less than 7 percent for all standards.

11.0 Analytical Procedures

12.0 Data Analysis and Calculations

Same as Method 7, Section 12.0, except replace Section 12.3 with
the following:
12.1 Total g NO2 Per Sample.
[GRAPHIC] [TIFF OMITTED] TR17OC00.211

Where:

5 = 100/20, the aliquot factor.

Note: If other than a 20-ml aliquot is used for analysis, the
factor 5 must be replaced by a corresponding factor.

13.0 Method Performance

13.1 Range. The analytical range of the method as outlined has
been determined to be 57 to 1500 milligrams NOX (as
NO2) per dry standard cubic meter, or 30 to 786 parts per
million by volume (ppmv) NOX.

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

1. National Institute for Occupational Safety and Health.
Recommendations for Occupational Exposure to Nitric Acid. In:
Occupational Safety and Health Reporter. Washington, D.C. Bureau of
National Affairs, Inc. 1976. p. 149.
2. Rennie, P.J., A.M. Sumner, and F.B. Basketter. Determination
of Nitrate in Raw, Potable, and Waste Waters by Ultraviolet
Spectrophotometry. Analyst. 104:837. September 1979.

17.0 Tables, Diagrams, Flowcharts, and Validation Data. [Reserved]

Method 7C--Determination of Nitrogen Oxide Emissions From
Stationary Sources (Alkaline Permanganate/Colorimetric Method)

1.0 Scope and Application

1.1 Analytes.

[[Page 61912]]

------------------------------------------------------------------------
Analyte CAS no. Sensitivity
------------------------------------------------------------------------
Nitrogen oxides (NOX), as NO2,
including:
Nitric oxide (NO)............. 10102-43-9 ....................
Nitrogen dioxide (NO2)........ 10102-44-07 ppmv
------------------------------------------------------------------------

1.2 Applicability. This method applies to the measurement of
NOX emissions from fossil-fuel fired steam generators,
electric utility plants, nitric acid plants, or other sources as
specified in the regulations.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

An integrated gas sample is extracted from the stack and passed
through impingers containing an alkaline potassium permanganate
solution; NOX (NO + NO2) emissions are oxidized
to NO2 and NO3. Then NO3-is
reduced to NO2-with cadmium, and the
NO2-is analyzed colorimetrically.

3.0 Definitions. [Reserved]

4.0 Interferences

Possible interferents are sulfur dioxides (SO2) and
ammonia (NH3).
4.1 High concentrations of SO2 could interfere because
SO2 consumes MnO4 (as does NOX) and,
therefore, could reduce the NOX collection efficiency.
However, when sampling emissions from a coal-fired electric utility
plant burning 2.1 percent sulfur coal with no control of SO2
emissions, collection efficiency was not reduced. In fact, calculations
show that sampling 3000 ppm SO2 will reduce the
MnO4 concentration by only 5 percent if all the
SO2 is consumed in the first impinger.
4.2 Ammonia (NH3) is slowly oxidized to
NO3- by the absorbing solution. At 100 ppm
NH3 in the gas stream, an interference of 6 ppm
NOX (11 mg NO2/m\3\) was observed when the sample
was analyzed 10 days after collection. Therefore, the method may not be
applicable to plants using NH3 injection to control
NOX emissions unless means are taken to correct the results.
An equation has been developed to allow quantification of the
interference and is discussed in Reference 5 of Section 16.0.

5.0 Safety

5.1 Disclaimer. This method may involve hazardous materials,
operations, and equipment. This test method may not address all of the
safety problems associated with its use. It is the responsibility of
the user of this test method to establish appropriate safety and health
practices and to determine the applicability of regulatory limitations
prior to performing this test method.
5.2 Corrosive Reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water for at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burns as thermal
burns.
5.2.1 Hydrochloric Acid (HCl). Highly toxic and corrosive. Causes
severe damage to skin. Vapors are highly irritating to eyes, skin,
nose, and lungs, causing severe damage. May cause bronchitis,
pneumonia, or edema of lungs. Exposure to vapor concentrations of 0.13
to 0.2 percent can be lethal in minutes. Will react with metals,
producing hydrogen.
5.2.2 Oxalic Acid (COOH)2. Poisonous. Irritating to
eyes, skin, nose, and throat.
5.2.3 Sodium Hydroxide (NaOH). Causes severe damage to eye tissues
and to skin. Inhalation causes irritation to nose, throat, and lungs.
Reacts exothermically with small amounts of water.
5.2.4 Potassium Permanganate (KMnO4). Caustic, strong
oxidizer. Avoid bodily contact with.

6.0 Equipment and Supplies

6.1 Sample Collection and Sample Recovery. A schematic of the
Method 7C sampling train is shown in Figure 7C-1, and component parts
are discussed below. Alternative apparatus and procedures are allowed
provided acceptable accuracy and precision can be demonstrated to the
satisfaction of the Administrator.
6.1.1 Probe. Borosilicate glass tubing, sufficiently heated to
prevent water condensation and equipped with an in-stack or heated out-
of-stack filter to remove particulate matter (a plug of glass wool is
satisfactory for this purpose). Stainless steel or Teflon tubing may
also be used for the probe.
6.1.2 Impingers. Three restricted-orifice glass impingers, having
the specifications given in Figure 7C-2, are required for each sampling
train. The impingers must be connected in series with leak-free glass
connectors. Stopcock grease may be used, if necessary, to prevent
leakage. (The impingers can be fabricated by a glass blower if not
available commercially.)
6.1.3 Glass Wool, Stopcock Grease, Drying Tube, Valve, Pump,
Barometer, and Vacuum Gauge and Rotameter. Same as in Method 6,
Sections 6.1.1.3, 6.1.1.4, 6.1.1.6, 6.1.1.7, 6.1.1.8, 6.1.2, and 6.1.3,
respectively.
6.1.4 Rate Meter. Rotameter, or equivalent, accurate to within 2
percent at the selected flow rate of between 400 and 500 ml/min (0.014
to 0.018 cfm). For rotameters, a range of 0 to 1 liter/min (0 to 0.035
cfm) is recommended.
6.1.5 Volume Meter. Dry gas meter (DGM) capable of measuring the
sample volume under the sampling conditions of 400 to 500 ml/min (0.014
to 0.018 cfm) for 60 minutes within an accuracy of 2 percent.
6.1.6 Filter. To remove NOX from ambient air, prepared
by adding 20 g of 5-angstrom molecular sieve to a cylindrical tube
(e.g., a polyethylene drying tube).
6.1.7 Polyethylene Bottles. 1-liter, for sample recovery.
6.1.8 Funnel and Stirring Rods. For sample recovery.
6.2 Sample Preparation and Analysis.
6.2.1 Hot Plate. Stirring type with 50- by 10-mm Teflon-coated
stirring bars.
6.2.2 Beakers. 400-, 600-, and 1000-ml capacities.
6.2.3 Filtering Flask. 500-ml capacity with side arm.
6.2.4 Buchner Funnel. 75-mm ID, with spout equipped with a 13-mm
ID by 90-mm long piece of Teflon tubing to minimize possibility of
aspirating sample solution during filtration.
6.2.5 Filter Paper. Whatman GF/C, 7.0-cm diameter.
6.2.6 Stirring Rods.
6.2.7 Volumetric Flasks. 100-, 200- or 250-, 500-, and 1000-ml
capacity.
6.2.8 Watch Glasses. To cover 600- and 1000-ml beakers.
6.2.9 Graduated Cylinders. 50- and 250-ml capacities.
6.2.10 Pipettes. Class A.
6.2.11 pH Meter. To measure pH from 0.5 to 12.0.
6.2.12 Burette. 50-ml with a micrometer type stopcock. (The
stopcock is Catalog No. 8225-t-05, Ace Glass, Inc., Post Office Box
996, Louisville, Kentucky 50201.) Place a glass wool plug in bottom of
burette. Cut off burette at a height of 43 cm (17 in.)

[[Page 61913]]

from the top of plug, and have a blower attach a glass funnel to top of
burette such that the diameter of the burette remains essentially
unchanged. Other means of attaching the funnel are acceptable.
6.2.13 Glass Funnel. 75-mm ID at the top.
6.2.14 Spectrophotometer. Capable of measuring absorbance at 540
nm; 1-cm cells are adequate.
6.2.15 Metal Thermometers. Bimetallic thermometers, range 0 to 150
deg.C (32 to 300 deg.F).
6.2.16 Culture Tubes. 20-by 150-mm, Kimax No. 45048.
6.2.17 Parafilm ``M.'' Obtained from American Can Company,
Greenwich, Connecticut 06830.
6.2.18 CO2 Measurement Equipment. Same as in Method 3,
Section 6.0.

7.0 Reagents and Standards

Unless otherwise indicated, it is intended that all reagents
conform to the specifications established by the Committee on
Analytical Reagents of the American Chemical Society, where such
specifications are available; otherwise, use the best available grade.
7.1 Sample Collection.
7.1.1 Water. Deionized distilled to conform to ASTM Specification
D 1193-77 or 91 Type 3 (incorporated by reference--see Sec. 60.17).
7.1.2 Potassium Permanganate, 4.0 Percent (w/w), Sodium Hydroxide,
2.0 Percent (w/w) solution (KMnO4/NaOH solution). Dissolve
40.0 g of KMnO4 and 20.0 g of NaOH in 940 ml of water.
7.2 Sample Preparation and Analysis.
7.2.1 Water. Same as in Section 7.1.1.
7.2.2 Oxalic Acid Solution. Dissolve 48 g of oxalic acid
[(COOH)22H2O] in water, and dilute to
500 ml. Do not heat the solution.
7.2.3 Sodium Hydroxide, 0.5 N. Dissolve 20 g of NaOH in water, and
dilute to 1 liter.
7.2.4 Sodium Hydroxide, 10 N. Dissolve 40 g of NaOH in water, and
dilute to 100 ml.
7.2.5 Ethylenediamine Tetraacetic Acid (EDTA) Solution, 6.5
percent (w/v). Dissolve 6.5 g of EDTA (disodium salt) in water, and
dilute to 100 ml. Dissolution is best accomplished by using a magnetic
stirrer.
7.2.6 Column Rinse Solution. Add 20 ml of 6.5 percent EDTA
solution to 960 ml of water, and adjust the pH to between 11.7 and 12.0
with 0.5 N NaOH.
7.2.7 Hydrochloric Acid (HCl), 2 N. Add 86 ml of concentrated HCl
to a 500 ml-volumetric flask containing water, dilute to volume, and
mix well. Store in a glass-stoppered bottle.
7.2.8 Sulfanilamide Solution. Add 20 g of sulfanilamide (melting
point 165 to 167 deg.C (329 to 333 deg.F)) to 700 ml of water. Add,
with mixing, 50 ml concentrated phosphoric acid (85 percent), and
dilute to 1000 ml. This solution is stable for at least 1 month, if
refrigerated.
7.2.9 N-(1-Naphthyl)-Ethylenediamine Dihydrochloride (NEDA)
Solution. Dissolve 0.5 g of NEDA in 500 ml of water. An aqueous
solution should have one absorption peak at 320 nm over the range of
260 to 400 nm. NEDA that shows more than one absorption peak over this
range is impure and should not be used. This solution is stable for at
least 1 month if protected from light and refrigerated.
7.2.10 Cadmium. Obtained from Matheson Coleman and Bell, 2909
Highland Avenue, Norwood, Ohio 45212, as EM Laboratories Catalog No.
2001. Prepare by rinsing in 2 N HCl for 5 minutes until the color is
silver-grey. Then rinse the cadmium with water until the rinsings are
neutral when tested with pH paper. CAUTION: H2 is liberated
during preparation. Prepare in an exhaust hood away from any flame or
combustion source.
7.2.11 Sodium Sulfite (NaNO2) Standard Solution,
Nominal Concentration, 1000 g NO2-/ml.
Desiccate NaNO2 overnight. Accurately weigh 1.4 to 1.6 g of
NaNO2 (assay of 97 percent NaNO2 or greater),
dissolve in water, and dilute to 1 liter. Calculate the exact
NO2-concentration using Equation 7C-1 in Section 12.2. This
solution is stable for at least 6 months under laboratory conditions.
7.2.12 Potassium Nitrate (KNO3) Standard Solution. Dry
KNO3 at 110 deg.C (230 deg.F) for 2 hours, and cool in a
desiccator. Accurately weigh 9 to 10 g of KNO3 to within 0.1
mg, dissolve in water, and dilute to 1 liter. Calculate the exact
NO3- concentration using Equation 7C-2 in Section
12.3. This solution is stable for 2 months without preservative under
laboratory conditions.
7.2.13 Spiking Solution. Pipette 7 ml of the KNO3
standard into a 100-ml volumetric flask, and dilute to volume.
7.2.14 Blank Solution. Dissolve 2.4 g of KMnO4 and 1.2
g of NaOH in 96 ml of water. Alternatively, dilute 60 ml of
KMnO4/NaOH solution to 100 ml.
7.2.15 Quality Assurance Audit Samples. Same as in Method 7,
Section 7.3.10. When requesting audit samples, specify that they be in
the appropriate concentration range for Method 7C.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Preparation of Sampling Train. Add 200 ml of KMnO4/
NaOH solution (Section 7.1.2) to each of three impingers, and assemble
the train as shown in Figure 7C-1. Adjust the probe heater to a
temperature sufficient to prevent water condensation.
8.2 Leak-Checks. Same as in Method 6, Section 8.2.
8.3 Sample Collection.
8.3.1 Record the initial DGM reading and barometric pressure.
Determine the sampling point or points according to the appropriate
regulations (e.g., Sec. 60.46(b)(5) of 40 CFR Part 60). Position the
tip of the probe at the sampling point, connect the probe to the first
impinger, and start the pump. Adjust the sample flow to a value between
400 and 500 ml/min (0.014 and 0.018 cfm). CAUTION: DO NOT EXCEED THESE
FLOW RATES. Once adjusted, maintain a constant flow rate during the
entire sampling run. Sample for 60 minutes. For relative accuracy (RA)
testing of continuous emission monitors, the minimum sampling time is 1
hour, sampling 20 minutes at each traverse point.

Note: When the SO2 concentration is greater than 1200
ppm, the sampling time may have to be reduced to 30 minutes to
eliminate plugging of the impinger orifice with MnO2. For
RA tests with SO2 greater than 1200 ppm, sample for 30
minutes (10 minutes at each point).

8.3.2 Record the DGM temperature, and check the flow rate at least
every 5 minutes. At the conclusion of each run, turn off the pump,
remove the probe from the stack, and record the final readings. Divide
the sample volume by the sampling time to determine the average flow
rate. Conduct the mandatory post-test leak-check. If a leak is found,
void the test run, or use procedures acceptable to the Administrator to
adjust the sample volume for the leakage.
8.4 CO2 Measurement. During sampling, measure the
CO2 content of the stack gas near the sampling point using
Method 3. The single-point grab sampling procedure is adequate,
provided the measurements are made at least three times (near the
start, midway, and before the end of a run), and the average
CO2 concentration is computed. The Orsat or Fyrite analyzer
may be used for this analysis.
8.5 Sample Recovery. Disconnect the impingers. Pour the contents
of the impingers into a 1-liter polyethylene bottle using a funnel and
a stirring rod (or other means) to prevent spillage. Complete the
quantitative transfer by

[[Page 61914]]

rinsing the impingers and connecting tubes with water until the
rinsings are clear to light pink, and add the rinsings to the bottle.
Mix the sample, and mark the solution level. Seal and identify the
sample container.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.2, 10.1-10.3................ Sampling Ensure accurate
equipment leak- measurement of
check and sample volume.
calibration.
10.4.......................... Spectrophotometer Ensure linearity of
calibration. spectrophotometer
response to
standards.
11.3.......................... Spiked sample Ensure reduction
analysis. efficiency of
column.
11.6.......................... Audit sample Evaluate analytical
analysis. technique,
preparation of
standards.
------------------------------------------------------------------------

10.0 Calibration and Standardizations

10.1 Volume Metering System. Same as Method 6, Section 10.1. For
detailed instructions on carrying out these calibrations, it is
suggested that Section 3.5.2 of Reference 4 of Section 16.0 be
consulted.
10.2 Temperature Sensors and Barometer. Same as in Method 6,
Sections 10.2 and 10.4, respectively.
10.3 Check of Rate Meter Calibration Accuracy (Optional).
Disconnect the probe from the first impinger, and connect the filter.
Start the pump, and adjust the rate meter to read between 400 and 500
ml/min (0.014 and 0.018 cfm). After the flow rate has stabilized, start
measuring the volume sampled, as recorded by the dry gas meter and the
sampling time. Collect enough volume to measure accurately the flow
rate. Then calculate the flow rate. This average flow rate must be less
than 500 ml/min (0.018 cfm) for the sample to be valid; therefore, it
is recommended that the flow rate be checked as above prior to each
test.
10.4 Spectrophotometer.
10.4.1 Dilute 5.0 ml of the NaNO2 standard solution to
200 ml with water. This solution nominally contains 25 g
NO2-/ml. Use this solution to prepare calibration
standards to cover the range of 0.25 to 3.00 g
NO2-/ml. Prepare a minimum of three standards
each for the linear and slightly nonlinear (described below) range of
the curve. Use pipettes for all additions.
10.4.2 Measure the absorbance of the standards and a water blank
as instructed in Section 11.5. Plot the net absorbance vs. g
NO2-/ml. Draw a smooth curve through the points.
The curve should be linear up to an absorbance of approximately 1.2
with a slope of approximately 0.53 absorbance units/g
NO2-/ml. The curve should pass through the
origin. The curve is slightly nonlinear from an absorbance of 1.2 to
1.6.

11.0 Analytical Procedures

11.1 Sample Stability. Collected samples are stable for at least
four weeks; thus, analysis must occur within 4 weeks of collection.
11.2 Sample Preparation.
11.2.1 Prepare a cadmium reduction column as follows: Fill the
burette with water. Add freshly prepared cadmium slowly, with tapping,
until no further settling occurs. The height of the cadmium column
should be 39 cm (15 in). When not in use, store the column under rinse
solution.

Note: The column should not contain any bands of cadmium fines.
This may occur if regenerated cadmium is used and will greatly
reduce the column lifetime.

11.2.2 Note the level of liquid in the sample container, and
determine whether any sample was lost during shipment. If a noticeable
amount of leakage has occurred, the volume lost can be determined from
the difference between initial and final solution levels, and this
value can then be used to correct the analytical result. Quantitatively
transfer the contents to a 1-liter volumetric flask, and dilute to
volume.
11.2.3 Take a 100-ml aliquot of the sample and blank (unexposed
KMnO4/NaOH) solutions, and transfer to 400-ml beakers
containing magnetic stirring bars. Using a pH meter, add concentrated
H2SO4 with stirring until a pH of 0.7 is
obtained. Allow the solutions to stand for 15 minutes. Cover the
beakers with watch glasses, and bring the temperature of the solutions
to 50 deg.C (122 deg.F). Keep the temperature below 60 deg.C (140
deg.F). Dissolve 4.8 g of oxalic acid in a minimum volume of water,
approximately 50 ml, at room temperature. Do not heat the solution. Add
this solution slowly, in increments, until the KMnO4
solution becomes colorless. If the color is not completely removed,
prepare some more of the above oxalic acid solution, and add until a
colorless solution is obtained. Add an excess of oxalic acid by
dissolving 1.6 g of oxalic acid in 50 ml of water, and add 6 ml of this
solution to the colorless solution. If suspended matter is present, add
concentrated H2SO4 until a clear solution is
obtained.
11.2.4 Allow the samples to cool to near room temperature, being
sure that the samples are still clear. Adjust the pH to between 11.7
and 12.0 with 10 N NaOH. Quantitatively transfer the mixture to a
Buchner funnel containing GF/C filter paper, and filter the
precipitate. Filter the mixture into a 500-ml filtering flask. Wash the
solid material four times with water. When filtration is complete, wash
the Teflon tubing, quantitatively transfer the filtrate to a 500-ml
volumetric flask, and dilute to volume. The samples are now ready for
cadmium reduction. Pipette a 50-ml aliquot of the sample into a 150-ml
beaker, and add a magnetic stirring bar. Pipette in 1.0 ml of 6.5
percent EDTA solution, and mix.
11.3 Determine the correct stopcock setting to establish a flow
rate of 7 to 9 ml/min of column rinse solution through the cadmium
reduction column. Use a 50-ml graduated cylinder to collect and measure
the solution volume. After the last of the rinse solution has passed
from the funnel into the burette, but before air entrapment can occur,
start adding the sample, and collect it in a 250-ml graduated cylinder.
Complete the quantitative transfer of the sample to the column as the
sample passes through the column. After the last of the sample has
passed from the funnel into the burette, start adding 60 ml of column
rinse solution, and collect the rinse solution until the solution just
disappears from the funnel. Quantitatively transfer the sample to a
200-ml volumetric flask (a 250-ml flask may be required), and dilute to
volume. The samples are now ready for NO2-analysis.

Note: Two spiked samples should be run with every group of
samples passed through the column. To do this, prepare two
additional 50-ml aliquots of the sample suspected to have the
highest NO2-concentration, and add 1 ml of the spiking
solution to these aliquots. If the spike recovery or column
efficiency (see Section 12.2) is below 95 percent, prepare a new
column, and repeat the cadmium reduction.

[[Page 61915]]

11.4 Repeat the procedures outlined in Sections 11.2 and 11.3 for
each sample and each blank.
11.5 Sample Analysis. Pipette 10 ml of sample into a culture tube.
Pipette in 10 ml of sulfanilamide solution and 1.4 ml of NEDA solution.
Cover the culture tube with parafilm, and mix the solution. Prepare a
blank in the same manner using the sample from treatment of the
unexposed KMnO4/NaOH solution. Also, prepare a calibration
standard to check the slope of the calibration curve. After a 10-minute
color development interval, measure the absorbance at 540 nm against
water. Read g NO2-/ml from the
calibration curve. If the absorbance is greater than that of the
highest calibration standard, use less than 10 ml of sample, and repeat
the analysis. Determine the NO2-concentration
using the calibration curve obtained in Section 10.4.

Note: Some test tubes give a high blank
NO2- value but culture tubes do not.

11.6 Audit Sample Analysis. Same as in Method 7, Section 11.4.

12.0 Data Analysis and Calculations

Carry out calculations, retaining at least one extra significant
figure beyond that of the acquired data. Round off figures after final
calculation.
12.1 Nomenclature.

B = Analysis of blank, g NO2-/ml.
C = Concentration of NOX as NO2, dry basis, mg/
dsm3.
E = Column efficiency, dimensionless
K2 = 10-3 mg/g.
m = Mass of NOX, as NO2, in sample, g.
Pbar = Barometric pressure, mm Hg (in. Hg).
Pstd = Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
s = Concentration of spiking solution, g NO3/ml.
S = Analysis of sample, g NO2-/ml.
Tm = Average dry gas meter absolute temperature, deg.K.
Tstd = Standard absolute temperature, 293 deg.K (528
deg.R).
Vm(std) = Dry gas volume measured by the dry gas meter,
corrected to standard conditions, dscm (dscf).
Vm = Dry gas volume as measured by the dry gas meter, scm
(scf).
x = Analysis of spiked sample, g NO2-/
ml.
X = Correction factor for CO2 collection = 100/(100 -
%CO2(V/V)).
y = Analysis of unspiked sample, g NO2-/
ml.
Y = Dry gas meter calibration factor.
1.0 ppm NO = 1.247 mg NO/m3 at STP.
1.0 ppm NO2 = 1.912 mg NO2/m3 at STP.
1 ft3 = 2.832 x 10-2 m3.

12.2 NO2 Concentration. Calculate the NO2
concentration of the solution (see Section 7.2.11) using the following
equation:
[GRAPHIC] [TIFF OMITTED] TR17OC00.212

12.3 NO3 Concentration. Calculate the NO3
concentration of the KNO3 solution (see Section 7.2.12)
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR17OC00.213

12.4 Sample Volume, Dry Basis, Corrected to Standard Conditions.
[GRAPHIC] [TIFF OMITTED] TR17OC00.214

Where:

K1 = 0.3855 deg.K/mm Hg for metric units.
K1 = 17.65 deg.R/in. Hg for English units.

12.5 Efficiency of Cadmium Reduction Column. Calculate this value
as follows:
[GRAPHIC] [TIFF OMITTED] TR17OC00.215

Where:

200 = Final volume of sample and blank after passing through the
column, ml.
1.0 = Volume of spiking solution added, ml.
46.01 = g NO2-/mole.
62.01 = g NO3-/mole.

12.6 Total g NO2.
[GRAPHIC] [TIFF OMITTED] TR17OC00.216

Where:

500 = Total volume of prepared sample, ml.
50 = Aliquot of prepared sample processed through cadmium column, ml.
100 = Aliquot of KMnO4/NaOH solution, ml.

[[Page 61916]]

1000 = Total volume of KMnO4/NaOH solution, ml.

12.7 Sample Concentration.
[GRAPHIC] [TIFF OMITTED] TR17OC00.217

13.0 Method Performance

13.1 Precision. The intra-laboratory relative standard deviation
for a single measurement is 2.8 and 2.9 percent at 201 and 268 ppm
NOX, respectively.
13.2 Bias. The method does not exhibit any bias relative to Method
7.
13.3 Range. The lower detectable limit is 13 mg NOX/
m3, as NO2 (7 ppm NOX) when sampling
at 500 ml/min for 1 hour. No upper limit has been established; however,
when using the recommended sampling conditions, the method has been
found to collect NOX emissions quantitatively up to 1782 mg
NOX/m3, as NO2 (932 ppm
NOX).

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

1. Margeson, J.H., W.J. Mitchell, J.C. Suggs, and M.R. Midgett.
Integrated Sampling and Analysis Methods for Determining
NOX Emissions at Electric Utility Plants. U.S.
Environmental Protection Agency, Research Triangle Park, NC. Journal
of the Air Pollution Control Association. 32:1210-1215. 1982.
2. Memorandum and attachment from J.H. Margeson, Source Branch,
Quality Assurance Division, Environmental Monitoring Systems
Laboratory, to The Record, EPA. March 30, 1983. NH3
Interference in Methods 7C and 7D.
3. Margeson, J.H., J.C. Suggs, and M.R. Midgett. Reduction of
Nitrate to Nitrite with Cadmium. Anal. Chem. 52:1955-57. 1980.
4. Quality Assurance Handbook for Air Pollution Measurement
Systems. Volume III--Stationary Source Specific Methods. U.S.
Environmental Protection Agency. Research Triangle Park, NC.
Publication No. EPA-600/4-77-027b. August 1977.
5. Margeson, J.H., et al. An Integrated Method for Determining
NOX Emissions at Nitric Acid Plants. Analytical
Chemistry. 47 (11):1801. 1975.

BILLING CODE 6560-50-P

[[Page 61917]]

17.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR17OC00.218

[[Page 61918]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.219

[[Page 61919]]

BILLING CODE 6560-50-C

Method 7D--Determination of Nitrogen Oxide Emissions From
Stationary Sources (Alkaline-Permanganate/Ion Chromatographic
Method)

Note: This method is not inclusive with respect to
specifications (e.g., equipment and supplies) and procedures (e.g.,
sampling and analytical) essential to its performance. Some material
is incorporated by reference from other methods in this part.
Therefore, to obtain reliable results, persons using this method
should have a thorough knowledge of at least the following
additional test methods: Method 1, Method 3, Method 6, Method 7, and
Method 7C.

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Nitrogen oxides (NOX), as NO2,
including:
Nitric oxide (NO)............. 10102-43-9
Nitrogen dioxide (NO2)........ 10102-44-0 7 ppmv
------------------------------------------------------------------------

2.0 Summary of Method

An integrated gas sample is extracted from the stack and passed
through impingers containing an alkaline-potassium permanganate
solution; NOX (NO + NO2) emissions are oxidized
to NO3-. Then NO3- is
analyzed by ion chromatography.

3.0 Definitions [Reserved]

4.0 Interferences

Same as in Method 7C, Section 4.0.

5.0 Safety

5.1 Disclaimer. This method may involve hazardous materials,
operations, and equipment. This test method may not address all of the
safety problems associated with its use. It is the responsibility of
the user of this test method to establish appropriate safety and health
practices and to determine the applicability of regulatory limitations
prior to performing this test method.
5.2 Corrosive reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water for at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burns as thermal
burns.
5.2.1 Hydrogen Peroxide (H2O2). Irritating
to eyes, skin, nose, and lungs. 30% H2O2 is a
strong oxidizing agent; avoid contact with skin, eyes, and combustible
material. Wear gloves when handling.
5.2.2 Sodium Hydroxide (NaOH). Causes severe damage to eye tissues
and to skin. Inhalation causes irritation to nose, throat, and lungs.
Reacts exothermically with limited amounts of water.
5.2.3 Potassium Permanganate (KMnO4). Caustic, strong
oxidizer. Avoid bodily contact with.

6.0 Equipment and Supplies

6.1 Sample Collection and Sample Recovery. Same as Method 7C,
Section 6.1. A schematic of the sampling train used in performing this
method is shown in Figure 7C-1 of Method 7C.
6.2 Sample Preparation and Analysis.
6.2.1 Magnetic Stirrer. With 25- by 10-mm Teflon-coated stirring
bars.
6.2.2 Filtering Flask. 500-ml capacity with sidearm.
6.2.3 Buchner Funnel. 75-mm ID, with spout equipped with a 13-mm
ID by 90-mm long piece of Teflon tubing to minimize possibility of
aspirating sample solution during filtration.
6.2.4 Filter Paper. Whatman GF/C, 7.0-cm diameter.
6.2.5 Stirring Rods.
6.2.6 Volumetric Flask. 250-ml.
6.2.7 Pipettes. Class A.
6.2.8 Erlenmeyer Flasks. 250-ml.
6.2.9 Ion Chromatograph. Equipped with an anion separator column
to separate NO3-, H3+
suppressor, and necessary auxiliary equipment. Nonsuppressed and other
forms of ion chromatography may also be used provided that adequate
resolution of NO3- is obtained. The system must
also be able to resolve and detect NO2-.

7.0 Reagents and Standards

Note: Unless otherwise indicated, it is intended that all
reagents conform to the specifications established by the Committee
on Analytical Reagents of the American Chemical Society, where such
specifications are available; otherwise, use the best available
grade.

7.1 Sample Collection.
7.1.1 Water. Deionized distilled to conform to ASTM specification
D 1193-77 or 91 Type 3 (incorporated by reference--see Sec. 60.17).
7.1.2 Potassium Permanganate, 4.0 Percent (w/w), Sodium Hydroxide,
2.0 Percent (w/w). Dissolve 40.0 g of KMnO4 and 20.0 g of
NaOH in 940 ml of water.
7.2 Sample Preparation and Analysis.
7.2.1 Water. Same as in Section 7.1.1.
7.2.2 Hydrogen Peroxide (H2O2), 5 Percent.
Dilute 30 percent H2O2 1:5 (v/v) with water.
7.2.3 Blank Solution. Dissolve 2.4 g of KMnO4 and 1.2 g
of NaOH in 96 ml of water. Alternatively, dilute 60 ml of
KMnO4/NaOH solution to 100 ml.
7.2.4 KNO3 Standard Solution. Dry KNO3 at
110 deg.C for 2 hours, and cool in a desiccator. Accurately weigh 9 to
10 g of KNO3 to within 0.1 mg, dissolve in water, and dilute
to 1 liter. Calculate the exact NO3-
concentration using Equation 7D-1 in Section 12.2. This solution is
stable for 2 months without preservative under laboratory conditions.
7.2.5 Eluent, 0.003 M NaHCO3/0.0024 M
Na2CO3. Dissolve 1.008 g NaHCO3 and
1.018 g Na2CO3 in water, and dilute to 4 liters.
Other eluents capable of resolving nitrate ion from sulfate and other
species present may be used.
7.2.6 Quality Assurance Audit Samples. Same as Method 7, Section
7.3.10. When requesting audit samples, specify that they be in the
appropriate concentration range for Method 7D.
8.0 Sample Collection, Preservation, Transport, and Storage.
8.1 Sampling. Same as in Method 7C, Section 8.1.
8.2 Sample Recovery. Same as in Method 7C, Section 8.2.
8.3 Sample Preparation for Analysis.

Note: Samples must be analyzed within 28 days of collection.

8.3.1 Note the level of liquid in the sample container, and
determine whether any sample was lost during shipment. If a noticeable
amount of

[[Page 61920]]

leakage has occurred, the volume lost can be determined from the
difference between initial and final solution levels, and this value
can then be used to correct the analytical result. Quantitatively
transfer the contents to a 1-liter volumetric flask, and dilute to
volume.
8.3.2 Sample preparation can be started 36 hours after collection.
This time is necessary to ensure that all NO2- is
converted to NO3- in the collection solution.
Take a 50-ml aliquot of the sample and blank, and transfer to 250-ml
Erlenmeyer flasks. Add a magnetic stirring bar. Adjust the stirring
rate to as fast a rate as possible without loss of solution. Add 5
percent H2O2 in increments of approximately 5 ml
using a 5-ml pipette. When the KMnO4 color appears to have
been removed, allow the precipitate to settle, and examine the
supernatant liquid. If the liquid is clear, the H2O2
addition is complete. If the KMnO4 color persists, add more
H2O2, with stirring, until the supernatant liquid
is clear.

Note: The faster the stirring rate, the less volume of
H2O2 that will be required to remove the
KMnO4.) Quantitatively transfer the mixture to a Buchner
funnel containing GF/C filter paper, and filter the precipitate. The
spout of the Buchner funnel should be equipped with a 13-mm ID by
90-mm long piece of Teflon tubing. This modification minimizes the
possibility of aspirating sample solution during filtration. Filter
the mixture into a 500-ml filtering flask. Wash the solid material
four times with water. When filtration is complete, wash the Teflon
tubing, quantitatively transfer the filtrate to a 250-ml volumetric
flask, and dilute to volume. The sample and blank are now ready for
NO3-analysis.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.2, 10.1-10.3................ Sampling Ensure accurate
equipment leak- measurement of
check and sample volume.
calibration.
10.4.......................... Spectrophotometer Ensure linearity of
calibration. spectrophotometer
response to
standards.
11.3.......................... Spiked sample Ensure reduction
analysis. efficiency of
column.
11.6.......................... Audit sample Evaluate analytical
analysis. technique,
preparation of
standards.
------------------------------------------------------------------------

10.0 Calibration and Standardizations

10.1 Dry Gas Meter (DGM) System.
10.1.1 Initial Calibration. Same as in Method 6, Section 10.1.1.
For detailed instructions on carrying out this calibration, it is
suggested that Section 3.5.2 of Citation 4 in Section 16.0 of Method 7C
be consulted.
10.1.2 Post-Test Calibration Check. Same as in Method 6, Section
10.1.2.
10.2 Thermometers for DGM and Barometer. Same as in Method 6,
Sections 10.2 and 10.4, respectively.
10.3 Ion Chromatograph.
10.3.1 Dilute a given volume (1.0 ml or greater) of the
KNO3 standard solution to a convenient volume with water,
and use this solution to prepare calibration standards. Prepare at
least four standards to cover the range of the samples being analyzed.
Use pipettes for all additions. Run standards as instructed in Section
11.2. Determine peak height or area, and plot the individual values
versus concentration in g NO3-/ml.
10.3.2 Do not force the curve through zero. Draw a smooth curve
through the points. The curve should be linear. With the linear curve,
use linear regression to determine the calibration equation.

11.0 Analytical Procedures

11.1 The following chromatographic conditions are recommended:
0.003 M NaHCO3/0.0024 Na2CO3 eluent
solution (Section 7.2.5), full scale range, 3 MHO; sample
loop, 0.5 ml; flow rate, 2.5 ml/min. These conditions should give a
NO3- retention time of approximately 15 minutes
(Figure 7D-1).
11.2 Establish a stable baseline. Inject a sample of water, and
determine whether any NO3- appears in the
chromatogram. If NO3- is present, repeat the
water load/injection procedure approximately five times; then re-inject
a water sample and observe the chromatogram. When no
NO3- is present, the instrument is ready for use.
Inject calibration standards. Then inject samples and a blank. Repeat
the injection of the calibration standards (to compensate for any drift
in response of the instrument). Measure the NO3-
peak height or peak area, and determine the sample concentration from
the calibration curve.

11.3 Audit Analysis. Same as in Method 7, Section 11.4

12.0 Data Analysis and Calculations

Carry out calculations, retaining at least one extra significant
figure beyond that of the acquired data. Round off figures after final
calculation.
12.1 Nomenclature. Same as in Method 7C, Section 12.1.
12.2 NO3- concentration. Calculate the
NO3- concentration in the KNO3
standard solution (see Section 7.2.4) using the following equation:
[GRAPHIC] [TIFF OMITTED] TR17OC00.220

12.3 Sample Volume, Dry Basis, Corrected to Standard Conditions.
Same as in Method 7C, Section 12.4.
12.4 Total g NO2 Per Sample.
[GRAPHIC] [TIFF OMITTED] TR17OC00.221

Where:

250 = Volume of prepared sample, ml.
1000 = Total volume of KMnO4 solution, ml.
50 = Aliquot of KMnO4/NaOH solution, ml.
46.01 = Molecular weight of NO3-.
62.01 = Molecular weight of NO3-.

12.5 Sample Concentration. Same as in Method 7C, Section 12.7.

[[Page 61921]]

13.0 Method Performance

13.1 Precision. The intra-laboratory relative standard deviation
for a single measurement is approximately 6 percent at 200 to 270 ppm
NOx.
13.2 Bias. The method does not exhibit any bias relative to Method
7.
13.3 Range. The lower detectable limit is similar to that of
Method 7C. No upper limit has been established; however, when using the
recommended sampling conditions, the method has been found to collect
NOX emissions quantitatively up to 1782 mg NOX/
m\3\, as NO2 (932 ppm NOx).

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

Same as Method 7C, Section 16.0, References 1, 2, 4, and 5.
BILLING CODE 6560-50-P

17.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR17OC00.222

BILLING CODE 6560-50-C
* * * * *

Method 8--Determination of Sulfuric Acid and Sulfur Dioxide
Emissions From Stationary Sources

[[Page 61922]]

of at least the following additional test methods: Method 1, Method
2, Method 3, Method 5, and Method 6.

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Sulfuric acid, including: 7664-93-9, 7449- 0.05 mg/m3 (0.03 x
Sulfuric acid (H2SO4) mist, 11-9. 10-7 lb/ft3).
Sulfur trioxide (SO3).
Sulfur dioxide (SO2).......... 7449-09-5........ 1.2 mg/m3 (3 x 10-9
lb/ft3).
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of H2SO4 (including H2SO4
mist and SO3) and gaseous SO2 emissions from
stationary sources.

Note: Filterable particulate matter may be determined along with
H2SO4 and SO2 (subject to the
approval of the Administrator) by inserting a heated glass fiber
filter between the probe and isopropanol impinger (see Section 6.1.1
of Method 6). If this option is chosen, particulate analysis is
gravimetric only; sulfuric acid is not determined separately.

1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

A gas sample is extracted isokinetically from the stack. The
H2SO4 and the SO2 are separated, and
both fractions are measured separately by the barium-thorin titration
method.

3.0 Definitions. [Reserved]

4.0 Interferences

4.1 Possible interfering agents of this method are fluorides, free
ammonia, and dimethyl aniline. If any of these interfering agents is
present (this can be determined by knowledge of the process),
alternative methods, subject to the approval of the Administrator, are
required.

5.0 Safety

6.0 Equipment and Supplies

6.1 Sample Collection. Same as Method 5, Section 6.1, with the
following additions and exceptions:
6.1.1 Sampling Train. A schematic of the sampling train used in
this method is shown in Figure 8-1; it is similar to the Method 5
sampling train, except that the filter position is different, and the
filter holder does not have to be heated. See Method 5, Section 6.1.1,
for details and guidelines on operation and maintenance.
6.1.1.1 Probe Liner. Borosilicate or quartz glass, with a heating
system to prevent visible condensation during sampling. Do not use
metal probe liners.
6.1.1.2 Filter Holder. Borosilicate glass, with a glass frit
filter support and a silicone rubber gasket. Other gasket materials
(e.g., Teflon or Viton) may be used, subject to the approval of the
Administrator. The holder design shall provide a positive seal against
leakage from the outside or around the filter. The filter holder shall
be placed between the first and second impingers. Do not heat the
filter holder.
6.1.1.3 Impingers. Four, of the Greenburg-Smith design, as shown
in Figure 8-1. The first and third impingers must have standard tips.
The second and fourth impingers must be modified by replacing the
insert with an approximately 13-mm (\1/2\-in.) ID glass tube, having an
unconstricted tip located 13 mm (\1/2\ in.) from the bottom of the
impinger. Similar collection systems, subject to the approval of the
Administrator, may be used.
6.1.1.4 Temperature Sensor. Thermometer, or equivalent, to measure
the temperature of the gas leaving the impinger train to within 1
deg.C (2 deg.F).
6.2 Sample Recovery. The following items are required for sample
recovery:
6.2.1 Wash Bottles. Two polyethylene or glass bottles, 500-ml.
6.2.2 Graduated Cylinders. Two graduated cylinders (volumetric
flasks may be used), 250-ml, 1-liter.
6.2.3 Storage Bottles. Leak-free polyethylene bottles, 1-liter
size (two for each sampling run).
6.2.4 Trip Balance. 500-g capacity, to measure to 0.5
g (necessary only if a moisture content analysis is to be done).
6.3 Analysis. The following items are required for sample
analysis:
6.3.1 Pipettes. Volumetric 10-ml, 100-ml.
6.3.2 Burette. 50-ml.
6.3.3 Erlenmeyer Flask. 250-ml (one for each sample, blank, and
standard).
6.3.4 Graduated Cylinder. 100-ml.
6.3.5 Dropping Bottle. To add indicator solution, 125-ml size.

7.0 Reagents and Standards

7.1 Sample Collection. The following reagents are required for
sample collection:
7.1.1 Filters and Silica Gel. Same as in Method 5, Sections 7.1.1
and 7.1.2, respectively.
7.1.2 Water. Same as in Method 6, Section 7.1.1.
7.1.3 Isopropanol, 80 Percent by Volume. Mix 800 ml of isopropanol
with 200 ml of water.

Note: Check for peroxide impurities using the procedure outlined
in Method 6, Section 7.1.2.1.

7.1.4 Hydrogen Peroxide (H\2\O\2\), 3 Percent by Volume. Dilute
100 ml of 30 percent H2O2) to 1 liter with water.
Prepare fresh daily.
7.1.5 Crushed Ice.
7.2 Sample Recovery. The reagents and standards required for
sample recovery are:
7.2.1 Water. Same as in Section 7.1.2.
7.2.2 Isopropanol, 80 Percent. Same as in Section 7.1.3.
7.3 Sample Analysis. Same as Method 6, Section 7.3.
7.3.1 Quality Assurance Audit Samples. When making compliance
determinations, and upon availability, audit samples may be obtained
from the appropriate EPA Regional Office or from the responsible
enforcement authority.

Note: The responsible enforcement authority should be notified
at least 30 days prior to the test date to allow sufficient time for
sample delivery.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Pretest Preparation. Same as Method 5, Section 8.1, except
that filters should be inspected but need not be desiccated, weighed,
or identified. If the

[[Page 61923]]

effluent gas can be considered dry (i.e., moisture-free), the silica
gel need not be weighed.
8.2 Preliminary Determinations. Same as Method 5, Section 8.2.
8.3 Preparation of Sampling Train. Same as Method 5, Section 8.3,
with the following exceptions:
8.3.1 Use Figure 8-1 instead of Figure 5-1.
8.3.2 Replace the second sentence of Method 5, Section 8.3.1 with:
Place 100 ml of 80 percent isopropanol in the first impinger, 100 ml of
3 percent H2O2 in both the second and third
impingers; retain a portion of each reagent for use as a blank
solution. Place about 200 g of silica gel in the fourth impinger.
8.3.3 Ignore any other statements in Section 8.3 of Method 5 that
are obviously not applicable to the performance of Method 8.

Note: If moisture content is to be determined by impinger
analysis, weigh each of the first three impingers (plus absorbing
solution) to the nearest 0.5 g, and record these weights. Weigh also
the silica gel (or silica gel plus container) to the nearest 0.5 g,
and record.)

8.4 Metering System Leak-Check Procedure. Same as Method 5,
Section 8.4.1.
8.5 Pretest Leak-Check Procedure. Follow the basic procedure in
Method 5, Section 8.4.2, noting that the probe heater shall be adjusted
to the minimum temperature required to prevent condensation, and also
that verbage such as ``* * * plugging the inlet to the filter holder *
* * '' found in Section 8.4.2.2 of Method 5 shall be replaced by `` * *
* plugging the inlet to the first impinger * * * ''. The pretest leak-
check is recommended, but is not required.
8.6 Sampling Train Operation. Follow the basic procedures in
Method 5, Section 8.5, in conjunction with the following special
instructions:
8.6.1 Record the data on a sheet similar to that shown in Figure
8-2 (alternatively, Figure 5-2 in Method 5 may be used). The sampling
rate shall not exceed 0.030 m\3\/min (1.0 cfm) during the run.
Periodically during the test, observe the connecting line between the
probe and first impinger for signs of condensation. If condensation
does occur, adjust the probe heater setting upward to the minimum
temperature required to prevent condensation. If component changes
become necessary during a run, a leak-check shall be performed
immediately before each change, according to the procedure outlined in
Section 8.4.3 of Method 5 (with appropriate modifications, as mentioned
in Section 8.5 of this method); record all leak rates. If the leakage
rate(s) exceeds the specified rate, the tester shall either void the
run or plan to correct the sample volume as outlined in Section 12.3 of
Method 5. Leak-checks immediately after component changes are
recommended, but not required. If these leak-checks are performed, the
procedure in Section 8.4.2 of Method 5 (with appropriate modifications)
shall be used.
8.6.2 After turning off the pump and recording the final readings
at the conclusion of each run, remove the probe from the stack. Conduct
a post-test (mandatory) leak-check as outlined in Section 8.4.4 of
Method 5 (with appropriate modifications), and record the leak rate. If
the post-test leakage rate exceeds the specified acceptable rate,
either correct the sample volume, as outlined in Section 12.3 of Method
5, or void the run.
8.6.3 Drain the ice bath and, with the probe disconnected, purge
the remaining part of the train by drawing clean ambient air through
the system for 15 minutes at the average flow rate used for sampling.

Note: Clean ambient air can be provided by passing air through a
charcoal filter. Alternatively, ambient air (without cleaning) may
be used.

8.7 Calculation of Percent Isokinetic. Same as Method 5, Section
8.6.
8.8 Sample Recovery. Proper cleanup procedure begins as soon as
the probe is removed from the stack at the end of the sampling period.
Allow the probe to cool. Treat the samples as follows:
8.8.1 Container No. 1.
8.8.1.1 If a moisture content analysis is to be performed, clean
and weigh the first impinger (plus contents) to the nearest 0.5 g, and
record this weight.
8.8.1.2 Transfer the contents of the first impinger to a 250-ml
graduated cylinder. Rinse the probe, first impinger, all connecting
glassware before the filter, and the front half of the filter holder
with 80 percent isopropanol. Add the isopropanol rinse solution to the
cylinder. Dilute the contents of the cylinder to 225 ml with 80 percent
isopropanol, and transfer the cylinder contents to the storage
container. Rinse the cylinder with 25 ml of 80 percent isopropanol, and
transfer the rinse to the storage container. Add the filter to the
solution in the storage container and mix. Seal the container to
protect the solution against evaporation. Mark the level of liquid on
the container, and identify the sample container.
8.8.2 Container No. 2.
8.8.2.1 If a moisture content analysis is to be performed, clean
and weigh the second and third impingers (plus contents) to the nearest
0.5 g, and record the weights. Also, weigh the spent silica gel (or
silica gel plus impinger) to the nearest 0.5 g, and record the weight.
8.8.2.2 Transfer the solutions from the second and third impingers
to a 1-liter graduated cylinder. Rinse all connecting glassware
(including back half of filter holder) between the filter and silica
gel impinger with water, and add this rinse water to the cylinder.
Dilute the contents of the cylinder to 950 ml with water. Transfer the
solution to a storage container. Rinse the cylinder with 50 ml of
water, and transfer the rinse to the storage container. Mark the level
of liquid on the container. Seal and identify the sample container.

9.0 Quality Control

9.1 Miscellaneous Quality Control Measures.

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
7.1.3......................... Isopropanol check Ensure acceptable
level of peroxide
impurities in
isopropanol.
8.4, 8.5, 10.1................ Sampling Ensure accurate
equipment leak- measurement of stack
check and gas flow rate,
calibration. sample volume.
10.2.......................... Barium standard Ensure normality
solution determination.
standardization.
11.2.......................... Replicate Ensure precision of
titrations. titration
determinations.
11.3.......................... Audit sample Evaluate analyst's
analysis. technique and
standards
preparation.
------------------------------------------------------------------------

9.2 Volume Metering System Checks. Same as Method 5, Section 9.2.

10.0 Calibration and Standardization

10.1 Sampling Equipment. Same as Method 5, Section 10.0.
10.2 Barium Standard Solution. Same as Method 6, Section 10.5.

[[Page 61924]]

11.0 Analytical Procedure

11.1. Sample Loss. Same as Method 6, Section 11.1.
11.2. Sample Analysis.
11.2.1 Container No. 1. Shake the container holding the
isopropanol solution and the filter. If the filter breaks up, allow the
fragments to settle for a few minutes before removing a sample aliquot.
Pipette a 100-ml aliquot of this solution into a 250-ml Erlenmeyer
flask, add 2 to 4 drops of thorin indicator, and titrate to a pink
endpoint using 0.0100 N barium standard solution. Repeat the titration
with a second aliquot of sample, and average the titration values.
Replicate titrations must agree within 1 percent or 0.2 ml, whichever
is greater.
11.2.2 Container No. 2. Thoroughly mix the solution in the
container holding the contents of the second and third impingers.
Pipette a 10-ml aliquot of sample into a 250-ml Erlenmeyer flask. Add
40 ml of isopropanol, 2 to 4 drops of thorin indicator, and titrate to
a pink endpoint using 0.0100 N barium standard solution. Repeat the
titration with a second aliquot of sample, and average the titration
values. Replicate titrations must agree within 1 percent or 0.2 ml,
whichever is greater.
11.2.3 Blanks. Prepare blanks by adding 2 to 4 drops of thorin
indicator to 100 ml of 80 percent isopropanol. Titrate the blanks in
the same manner as the samples.
11.3 Audit Sample Analysis.
11.3.1 When the method is used to analyze samples to demonstrate
compliance with a source emission regulation, EPA audit samples must be
analyzed, subject to availability.
11.3.2 Concurrently analyze audit samples and the compliance
samples in the same manner to evaluate the technique of the analyst and
the standards preparation.

Note: It is recommended that known quality control samples be
analyzed prior to the compliance and audit sample analyses to
optimize the system accuracy and precision. These quality control
samples may be obtained by contacting the appropriate EPA regional
Office or the responsible enforcement authority.

11.3.3 The same analyst, analytical reagents, and analytical
system shall be used for the compliance samples and the EPA audit
samples. If this condition is met, duplicate auditing of subsequent
compliance analyses for the same enforcement agency within a 30-day
period is waived. Audit samples may not be used to validate different
compliance samples under the jurisdiction of separate enforcement
agencies, unless prior arrangements have been made with both
enforcement agencies.
11.4 Audit Sample Results.
11.4.1 Calculate the audit sample concentrations in mg/dscm and
submit results using the instructions provided with the audit samples.
11.4.2 Report the results of the audit samples and the compliance
determination samples along with their identification numbers, and the
analyst's name to the responsible enforcement authority. Include this
information with reports of any subsequent compliance analyses for the
same enforcement authority during the 30-day period.
11.4.3 The concentrations of the audit samples obtained by the
analyst shall agree within 5 percent of the actual concentrations. If
the 5 percent specification is not met, reanalyze the compliance and
audit samples, and include initial and reanalysis values in the test
report.
11.4.4 Failure to meet the 5 percent specification may require
retests until the audit problems are resolved. However, if the audit
results do not affect the compliance or noncompliance status of the
affected facility, the Administrator may waive the reanalysis
requirement, further audits, or retests and accept the results of the
compliance test. While steps are being taken to resolve audit analysis
problems, the Administrator may also choose to use the data to
determine the compliance or noncompliance status of the affected
facility.

12.0 Data Analysis and Calculations

Carry out calculations retaining at least one extra significant
figure beyond that of the acquired data. Round off figures after final
calculation.
12.1 Nomenclature. Same as Method 5, Section 12.1, with the
following additions and exceptions:

Ca = Actual concentration of SO2 in audit sample,
mg/dscm.
Cd = Determined concentration of SO2 in audit
sample, mg/dscm.
CH2SO4 = Sulfuric acid (including SO3)
concentration, g/dscm (lb/dscf).
CSO2 = Sulfur dioxide concentration, g/dscm (lb/dscf).
N = Normality of barium perchlorate titrant, meq/ml.
RE = Relative error of QA audit sample analysis, percent
Va = Volume of sample aliquot titrated, 100 ml for
H2SO4 and 10 ml for SO2.
Vsoln = Total volume of solution in which the sample is
contained, 250 ml for the SO2 sample and 1000 ml for the
H2SO4 sample.
Vt = Volume of barium standard solution titrant used for the
sample, ml.
Vtb = Volume of barium standard solution titrant used for
the blank, ml.

12.2 Average Dry Gas Meter Temperature and Average Orifice
Pressure Drop. See data sheet (Figure 8-2).
12.3 Dry Gas Volume. Same as Method 5, Section 12.3.
12.4 Volume of Water Vapor Condensed and Moisture Content.
Calculate the volume of water vapor using Equation 5-2 of Method 5; the
weight of water collected in the impingers and silica gel can be
converted directly to milliliters (the specific gravity of water is 1
g/ml). Calculate the moisture content of the stack gas (Bws)
using Equation 5-3 of Method 5. The Note in Section 12.5 of Method 5
also applies to this method. Note that if the effluent gas stream can
be considered dry, the volume of water vapor and moisture content need
not be calculated.
12.5 Sulfuric Acid Mist (Including SO3) Concentration.
[GRAPHIC] [TIFF OMITTED] TR17OC00.223

Where:

K3 = 0.04904 g/meq for metric units,
K3 = 1.081 x 10-4 lb/meq for English units.

12.6 Sulfur Dioxide Concentration.
[GRAPHIC] [TIFF OMITTED] TR17OC00.224

[[Page 61925]]

Where:

K4 = 0.03203 g/meq for metric units,
K4 = 7.061 x 10-5 lb/meq for English units.

12.7 Isokinetic Variation. Same as Method 5, Section 12.11.
12.8 Stack Gas Velocity and Volumetric Flow Rate. Calculate the
average stack gas velocity and volumetric flow rate, if needed, using
data obtained in this method and the equations in Sections 12.6 and
12.7 of Method 2.
12.9 Relative Error (RE) for QA Audit Samples. Same as Method 6,
Section 12.4.

13.0 Method Performance

13.1 Analytical Range. Collaborative tests have shown that the
minimum detectable limits of the method are 0.06 mg/m3 (4
x 10-9 lb/ft3) for H2SO4
and 1.2 mg/m3 (74 x 10-9 lb/ft3) for
SO2. No upper limits have been established. Based on
theoretical calculations for 200 ml of 3 percent
H2O2 solution, the upper concentration limit for
SO2 in a 1.0 m3 (35.3 ft3) gas sample
is about 12,000 mg/m3 (7.7 x 10-4 lb/
ft3). The upper limit can be extended by increasing the
quantity of peroxide solution in the impingers.

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

Same as Section 17.0 of Methods 5 and 6.
BILLING CODE 6560-50-C

[[Page 61926]]

17.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR17OC00.225

[[Page 61927]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.226

BILLING CODE 6560-50-C

[[Page 61928]]

Method 10A--Determination of Carbon Monoxide Emissions in
Certifying Continuous Emission Monitoring Systems at Petroleum
Refineries

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Carbon monoxide (CO).............. 630-08-0 3 ppmv
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of CO emissions at petroleum refineries. This method serves as the
reference method in the relative accuracy test for nondispersive
infrared (NDIR) CO continuous emission monitoring systems (CEMS) that
are required to be installed in petroleum refineries on fluid catalytic
cracking unit catalyst regenerators (Sec. 60.105(a)(2) of this part).
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

An integrated gas sample is extracted from the stack, passed
through an alkaline permanganate solution to remove sulfur oxides and
nitrogen oxides, and collected in a Tedlar bag. The CO concentration in
the sample is measured spectrophotometrically using the reaction of CO
with p-sulfaminobenzoic acid.

3.0 Definitions. [Reserved]

4.0 Interferences

Sulfur oxides, nitric oxide, and other acid gases interfere with
the colorimetric reaction. They are removed by passing the sampled gas
through an alkaline potassium permanganate scrubbing solution. Carbon
dioxide (CO2) does not interfere, but, because it is removed
by the scrubbing solution, its concentration must be measured
independently and an appropriate volume correction made to the sampled
gas.

5.0 Safety

5.1 Disclaimer. This method may involve hazardous materials,
operations, and equipment. This test method may not address all of the
safety problems associated with its use. It is the responsibility of
the user of this test method to establish appropriate safety and health
practices and determine the applicability of regulatory limitations
prior to performing this test method. The analyzer users manual should
be consulted for specific precautions to be taken with regard to the
analytical procedure.
5.2 Corrosive reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water for at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burns as thermal
burns.
5.2.1 Sodium Hydroxide (NaOH). Causes severe damage to eyes and
skin. Inhalation causes irritation to nose, throat, and lungs. Reacts
exothermically with limited amounts of water.

6.0 Equipment and Supplies

6.1 Sample Collection. The sampling train shown in Figure 10A-1 is
required for sample collection. Component parts are described below:
6.1.1 Probe. Stainless steel, sheathed Pyrex glass, or equivalent,
equipped with a glass wool plug to remove particulate matter.
6.1.2 Sample Conditioning System. Three Greenburg-Smith impingers
connected in series with leak-free connections.
6.1.3 Pump. Leak-free pump with stainless steel and Teflon parts
to transport sample at a flow rate of 300 ml/min (0.01 ft\3\/min) to
the flexible bag.
6.1.4 Surge Tank. Installed between the pump and the rate meter to
eliminate the pulsation effect of the pump on the rate meter.
6.1.5 Rate Meter. Rotameter, or equivalent, to measure flow rate
at 300 ml/min (0.01 ft\3\/min). Calibrate according to Section 10.2.
6.1.6 Flexible Bag. Tedlar, or equivalent, with a capacity of 10
liters (0.35 ft\3\) and equipped with a sealing quick-connect plug. The
bag must be leak-free according to Section 8.1. For protection, it is
recommended that the bag be enclosed within a rigid container.
6.1.7 Valves. Stainless-steel needle valve to adjust flow rate,
and stainless-steel three-way valve, or equivalent.
6.1.8 CO2 Analyzer. Fyrite, or equivalent, to measure
CO2 concentration to within O.5 percent.
6.1.9 Volume Meter. Dry gas meter, capable of measuring the sample
volume under calibration conditions of 300 ml/min (0.01 ft\3\/min) for
10 minutes.
6.1.10 Pressure Gauge. A water filled U-tube manometer, or
equivalent, of about 30 cm (12 in.) to leak-check the flexible bag.
6.2 Sample Analysis.
6.2.1 Spectrophotometer. Single- or double-beam to measure
absorbance at 425 and 600 nm. Slit width should not exceed 20 nm.
6.2.2 Spectrophotometer Cells. 1-cm pathlength.
6.2.3 Vacuum Gauge. U-tube mercury manometer, 1 meter (39 in.),
with 1-mm divisions, or other gauge capable of measuring pressure to
within 1 mm Hg.
6.2.4 Pump. Capable of evacuating the gas reaction bulb to a
pressure equal to or less than 40 mm Hg absolute, equipped with coarse
and fine flow control valves.
6.2.5 Barometer. Mercury, aneroid, or other barometer capable of
measuring atmospheric pressure to within 1 mm Hg.
6.2.6 Reaction Bulbs. Pyrex glass, 100-ml with Teflon stopcock
(Figure 10A-2), leak-free at 40 mm Hg, designed so that 10 ml of the
colorimetric reagent can be added and removed easily and accurately.
Commercially available gas sample bulbs such as Supelco Catalog No. 2-
2161 may also be used.
6.2.7 Manifold. Stainless steel, with connections for three
reaction bulbs and the appropriate connections for the manometer and
sampling bag as shown in Figure 10A-3.
6.2.8 Pipets. Class A, 10-ml size.
6.2.9 Shaker Table. Reciprocating-stroke type such as Eberbach
Corporation, Model 6015. A rocking arm or rotary-motion type shaker may
also be used. The shaker must be large enough to accommodate at least
six gas sample bulbs simultaneously. It may be necessary to construct a
table top extension for most commercial shakers to provide sufficient
space for the needed bulbs (Figure 10A-4).
6.2.10 Valve. Stainless steel shut-off valve.

[[Page 61929]]

6.2.11 Analytical Balance. Capable of weighing to 0.1 mg.

7.0 Reagents and Standards

Unless otherwise indicated, all reagents shall conform to the
specifications established by the Committee on Analytical Reagents of
the American Chemical Society, where such specifications are available;
otherwise, the best available grade shall be used.
7.1 Sample Collection.
7.1.1 Water. Deionized distilled, to conform to ASTM D 1193-77 or
91, Type 3 (incorporated by reference--see Sec. 60.17). If high
concentrations of organic matter are not expected to be present, the
potassium permanganate test for oxidizable organic matter may be
omitted.
7.1.2 Alkaline Permanganate Solution, 0.25 M KMnO4/1.5
M Sodium Hydroxide (NaOH). Dissolve 40 g KMnO4 and 60 g NaOH
in approximately 900 ml water, cool, and dilute to 1 liter.
7.2 Sample Analysis.
7.2.1 Water. Same as in Section 7.1.1.
7.2.2 1 M Sodium Hydroxide Solution. Dissolve 40 g NaOH in
approximately 900 ml of water, cool, and dilute to 1 liter.
7.2.3 0.1 M NaOH Solution. Dilute 50 ml of the 1 M NaOH solution
prepared in Section 7.2.2 to 500 ml.
7.2.4 0.1 M Silver Nitrate (AgNO3) Solution. Dissolve
8.5 g AgNO3 in water, and dilute to 500 ml.
7.2.5 0.1 M Para-Sulfaminobenzoic Acid (p-SABA) Solution. Dissolve
10.0 g p-SABA in 0.1 M NaOH, and dilute to 500 ml with 0.1 M NaOH.
7.2.6 Colorimetric Solution. To a flask, add 100 ml of 0.1 M p-
SABA solution and 100 ml of 0.1 M AgNO3 solution. Mix, and
add 50 ml of 1 M NaOH with shaking. The resultant solution should be
clear and colorless. This solution is acceptable for use for a period
of 2 days.
7.2.7 Standard Gas Mixtures. Traceable to National Institute of
Standards and Technology (NIST) standards and containing between 50 and
1000 ppm CO in nitrogen. At least two concentrations are needed to span
each calibration range used (Section 10.3). The calibration gases must
be certified by the manufacturer to be within 2 percent of the
specified concentrations.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Sample Bag Leak-Checks. While a bag leak-check is required
after bag use, it should also be done before the bag is used for sample
collection. The bag should be leak-checked in the inflated and deflated
condition according to the following procedure:
8.1.1 Connect the bag to a water manometer, and pressurize the bag
to 5 to 10 cm H2O (2 to 4 in H2O). Allow the bag
to stand for 60 minutes. Any displacement in the water manometer
indicates a leak.
8.1.2 Evacuate the bag with a leakless pump that is connected to
the downstream side of a flow indicating device such as a 0- to 100-ml/
min rotameter or an impinger containing water. When the bag is
completely evacuated, no flow should be evident if the bag is leak-
free.
8.2 Sample Collection.
8.2.1 Evacuate the Tedlar bag completely using a vacuum pump.
Assemble the apparatus as shown in Figure 10A-1. Loosely pack glass
wool in the tip of the probe. Place 400 ml of alkaline permanganate
solution in the first two impingers and 250 ml in the third. Connect
the pump to the third impinger, and follow this with the surge tank,
rate meter, and 3-way valve. Do not connect the Tedlar bag to the
system at this time.
8.2.2 Leak-check the sampling system by plugging the probe inlet,
opening the 3-way valve, and pulling a vacuum of approximately 250 mm
Hg on the system while observing the rate meter for flow. If flow is
indicated on the rate meter, do not proceed further until the leak is
found and corrected.
8.2.3 Purge the system with sample gas by inserting the probe into
the stack and drawing the sample gas through the system at 300 ml/min
10 percent for 5 minutes. Connect the evacuated Tedlar bag
to the system, record the starting time, and sample at a rate of 300
ml/min for 30 minutes, or until the Tedlar bag is nearly full. Record
the sampling time, the barometric pressure, and the ambient
temperature. Purge the system as described above immediately before
each sample.
8.2.4 The scrubbing solution is adequate for removing sulfur
oxides and nitrogen oxides from 50 liters (1.8 ft\3\) of stack gas when
the concentration of each is less than 1,000 ppm and the CO2
concentration is less than 15 percent. Replace the scrubber solution
after every fifth sample.
8.3 Carbon Dioxide Measurement. Measure the CO2 content
in the stack to the nearest 0.5 percent each time a CO sample is
collected. A simultaneous grab sample analyzed by the Fyrite analyzer
is acceptable.

9.0 Quality Control

9.1 Miscellaneous Quality Control Measures.

9.2 Volume Metering System Checks. Same as Method 5, Section 9.2.

10.0 Calibration and Standardization

Note: Maintain a laboratory log of all calibrations.

10.1 Gas Bulb Calibration. Weigh the empty bulb to the nearest 0.1
g. Fill the bulb to the stopcock with water, and again weigh to the
nearest 0.1 g. Subtract the tare weight, and calculate the volume in
liters to three significant figures using the density of water at the
measurement temperature. Record the volume on the bulb. Alternatively,
mark an identification number on the bulb, and record the volume in a
notebook.
10.2 Rate Meter Calibration. Assemble the system as shown in
Figure 10A-1 (the impingers may be removed), and attach a volume meter
to the probe inlet. Set the rotameter at 300 ml/min, record the volume
meter reading, start the pump, and pull ambient air through the system
for 10 minutes. Record the final volume meter reading. Repeat the
procedure and average the results to determine the volume of gas that
passed through the system.
10.3 Spectrophotometer Calibration Curve.
10.3.1 Collect the standards as described in Section 8.2. Prepare
at least two sets of three bulbs as standards to span the 0 to 400 or
400 to 1000 ppm range. If any samples span both concentration ranges,
prepare a calibration curve for each range using separate reagent
blanks. Prepare a set of three bulbs containing colorimetric reagent
but no CO to serve as a reagent

[[Page 61930]]

blank. Analyze each standard and blank according to the sample analysis
procedure of Section 11.0 Reject the standard set where any of the
individual bulb absorbances differs from the set mean by more than 10
percent.
10.3.2 Calculate the average absorbance for each set (3 bulbs) of
standards using Equation 10A-1 and Table 10A-1. Construct a graph of
average absorbance for each standard against its corresponding
concentration. Draw a smooth curve through the points. The curve should
be linear over the two concentration ranges discussed in Section 13.3.

11.0 Analytical Procedure

11.1 Assemble the system shown in Figure 10A-3, and record the
information required in Table 10A-1 as it is obtained. Pipet 10.0 ml of
the colorimetric reagent into each gas reaction bulb, and attach the
bulbs to the system. Open the stopcocks to the reaction bulbs, but
leave the valve to the Tedlar bag closed. Turn on the pump, fully open
the coarse-adjust flow valve, and slowly open the fine-adjust valve
until the pressure is reduced to at least 40 mm Hg. Now close the
coarse adjust valve, and observe the manometer to be certain that the
system is leak-free. Wait a minimum of 2 minutes. If the pressure has
increased less than 1 mm Hg, proceed as described below. If a leak is
present, find and correct it before proceeding further.
11.2 Record the vacuum pressure (Pv) to the nearest 1
mm Hg, and close the reaction bulb stopcocks. Open the Tedlar bag
valve, and allow the system to come to atmospheric pressure. Close the
bag valve, open the pump coarse adjust valve, and evacuate the system
again. Repeat this fill/evacuation procedure at least twice to flush
the manifold completely. Close the pump coarse adjust valve, open the
Tedlar bag valve, and let the system fill to atmospheric pressure. Open
the stopcocks to the reaction bulbs, and let the entire system come to
atmospheric pressure. Close the bulb stopcocks, remove the bulbs,
record the room temperature and barometric pressure (Pbar,
to nearest mm Hg), and place the bulbs on the shaker table with their
main axis either parallel to or perpendicular to the plane of the table
top. Purge the bulb-filling system with ambient air for several minutes
between samples. Shake the samples for exactly 2 hours.
11.3 Immediately after shaking, measure the absorbance (A) of each
bulb sample at 425 nm if the concentration is less than or equal to 400
ppm CO or at 600 nm if the concentration is above 400 ppm.

Note: This may be accomplished with multiple bulb sets by
sequentially collecting sets and adding to the shaker at staggered
intervals, followed by sequentially removing sets from the shaker
for absorbance measurement after the two-hour designated intervals
have elapsed.

11.4 Use a small portion of the sample to rinse a
spectrophotometer cell several times before taking an aliquot for
analysis. If one cell is used to analyze multiple samples, rinse the
cell with deionized distilled water several times between samples.
Prepare and analyze standards and a reagent blank as described in
Section 10.3. Use water as the reference. Reject the analysis if the
blank absorbance is greater than 0.1. All conditions should be the same
for analysis of samples and standards. Measure the absorbances as soon
as possible after shaking is completed.
11.5 Determine the CO concentration of each bag sample using the
calibration curve for the appropriate concentration range as discussed
in Section 10.3.

12.0 Calculations and Data Analysis

Carry out calculations retaining at least one extra decimal figure
beyond that of the acquired data. Round off figures after final
calculation.
12.1 Nomenclature.

A = Sample absorbance, uncorrected for the reagent blank.
Ar = Absorbance of the reagent blank.
As = Average sample absorbance per liter, units/liter.
Bw = Moisture content in the bag sample.
C = CO concentration in the stack gas, dry basis, ppm.
Cb = CO concentration of the bag sample, dry basis, ppm.
Cg = CO concentration from the calibration curve, ppm.
F = Volume fraction of CO2 in the stack.
n = Number of reaction bulbs used per bag sample.
Pb = Barometric pressure, mm Hg.
Pv = Residual pressure in the sample bulb after evacuation,
mm Hg.
Pw = Vapor pressure of H2O in the bag (from Table
10A-2), mm Hg.
Vb = Volume of the sample bulb, liters.
Vr = Volume of reagent added to the sample bulb, 0.0100
liter.

12.2 Average Sample Absorbance per Liter. Calculate As
for each gas bulb using Equation 10A-1, and record the value in Table
10A-1. Calculate the average As for each bag sample, and
compare the three values to the average. If any single value differs by
more than 10 percent from the average, reject this value, and calculate
a new average using the two remaining values.
[GRAPHIC] [TIFF OMITTED] TR17OC00.227

Note: A and Ar must be at the same wavelength.

12.3 CO Concentration in the Bag. Calculate Cb using
Equations 10A-2 and 10A-3. If condensate is visible in the Tedlar bag,
calculate Bw using Table 10A-2 and the temperature and
barometric pressure in the analysis room. If condensate is not visible,
calculate Bw using the temperature and barometric pressure
at the sampling site.
[GRAPHIC] [TIFF OMITTED] TR17OC00.228

[GRAPHIC] [TIFF OMITTED] TR17OC00.229

12.4 CO Concentration in the Stack.
[GRAPHIC] [TIFF OMITTED] TR17OC00.230

13.0 Method Performance

13.1 Precision. The estimated intralaboratory standard deviation
of the method is 3 percent of the mean for gas samples analyzed in
duplicate in the concentration range of 39 to 412 ppm. The
interlaboratory precision has not been established.
13.2 Accuracy. The method contains no significant biases when
compared to an NDIR analyzer calibrated with NIST standards.
13.3 Range. Approximately 3 to 1800 ppm CO. Samples having
concentrations below 400 ppm are analyzed at 425 nm, and samples having
concentrations above 400 ppm are analyzed at 600 nm.
13.4 Sensitivity. The detection limit is 3 ppmv based on a change
in concentration equal to three times the standard deviation of the
reagent blank solution.
13.5 Stability. The individual components of the colorimetric
reagent are stable for at least 1 month. The colorimetric reagent must
be used within 2 days after preparation to avoid excessive blank
correction. The samples in the Tedlar bag should be stable for at least
1 week if the bags are leak-free.

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

1. Butler, F.E., J.E. Knoll, and M.R. Midgett. Development and
Evaluation of Methods for Determining Carbon Monoxide Emissions.

[[Page 61931]]

U.S. Environmental Protection Agency, Research Triangle Park, N.C.
June 1985. 33 pp.
2. Ferguson, B.B., R.E. Lester, and W.J. Mitchell. Field
Evaluation of Carbon Monoxide and Hydrogen Sulfide Continuous
Emission Monitors at an Oil Refinery. U.S. Environmental Protection
Agency, Research Triangle Park, N.C. Publication No. EPA-600/4-82-
054. August 1982. 100 pp.
3. Lambert, J.L., and R.E. Weins. Induced Colorimetric Method
for Carbon Monoxide. Analytical Chemistry. 46(7):929-930. June 1974.
4. Levaggi, D.A., and M. Feldstein. The Colorimetric
Determination of Low Concentrations of Carbon Monoxide. Industrial
Hygiene Journal. 25:64-66. January-February 1964.
5. Repp, M. Evaluation of Continuous Monitors For Carbon
Monoxide in Stationary Sources. U.S. Environmental Protection
Agency. Research Triangle Park, N.C. Publication No. EPA-600/2-77-
063. March 1977. 155 pp.
6. Smith, F., D.E. Wagoner, and R.P. Donovan. Guidelines for
Development of a Quality Assurance Program: Volume VIII--
Determination of CO Emissions from Stationary Sources by NDIR
Spectrometry. U.S. Environmental Protection Agency. Research
Triangle Park, N.C. Publication No. EPA-650/4-74-005-h. February
1975. 96 pp.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

Table 10A-1.--Data Recording Sheet for Samples Analyzed in Triplicate
--------------------------------------------------------------------------------------------------------------------------------------------------------
Partial
Room Bulb Reagent pressure Shaking Abs
Sample No./type temp Stack Bulb vol. vol. in of gas in Pb, mm time, versus A-Ar As Avg As
deg.C %CO2 No. liters bulb, bulb, mm Hg min water
liter Hg
--------------------------------------------------------------------------------------------------------------------------------------------------------
blank
--------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------
Std. 1
------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------
Std. 2
------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------
Sample 1
------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------
Sample 2
------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------
Sample 3
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table 10A-2.--Moisture Correction
----------------------------------------------------------------------------------------------------------------
Vapor Vapor
Temperature deg.C pressure of Temperature pressure of
H2,O, mm Hg deg.C H2, mm Hg
----------------------------------------------------------------------------------------------------------------
4............................................................... 6.1 18 15.5
6............................................................... 7.0 20 17.5
8............................................................... 8.0 22 19.8
10.............................................................. 9.2 24 22.4
12.............................................................. 10.5 26 25.2
14.............................................................. 12.0 28 28.3
16.............................................................. 13.6 30 31.8
----------------------------------------------------------------------------------------------------------------

BILLING CODE 6560-50-P

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BILLING CODE 6560-50-C

Method 10B--Determination of Carbon Monoxide Emissions From
Stationary Sources

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Carbon monoxide (CO)............. 630-08-0 Not determined.
------------------------------------------------------------------------

1.2 Applicability. This method applies to the measurement of CO
emissions at petroleum refineries and from other sources when specified
in an applicable subpart of the regulations.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 An integrated gas sample is extracted from the sampling point,
passed through a conditioning system to remove interferences, and
collected in a Tedlar bag. The CO is separated from the sample by gas
chromatography (GC) and catalytically reduced to methane
(CH4) which is determined by flame ionization detection
(FID). The analytical portion of this method is identical to applicable
sections in Method 25 detailing CO measurement.

3.0 Definitions. [Reserved]

4.0 Interferences

4.1 Carbon dioxide (CO2) and organics potentially can
interfere with the analysis. Most of the CO2 is removed from
the sample by the alkaline permanganate conditioning system; any

[[Page 61936]]

residual CO2 and organics are separated from the CO by GC.

5.0 Safety

6.0 Equipment and Supplies

6.1 Sample Collection. Same as in Method 10A, Section 6.1.
6.2 Sample Analysis. A GC/FID analyzer, capable of quantifying CO
in the sample and consisting of at least the following major
components, is required for sample analysis. [Alternatively, complete
Method 25 analytical systems (Method 25, Section 6.3) are acceptable
alternatives when calibrated for CO and operated in accordance with the
Method 25 analytical procedures (Method 25, Section 11.0).]
6.2.1 Separation Column. A column capable of separating CO from
CO2 and organic compounds that may be present. A 3.2-mm (\1/
8\-in.) OD stainless steel column packed with 1.7 m (5.5 ft.) of 60/80
mesh Carbosieve S-II (available from Supelco) has been used
successfully for this purpose.
6.2.2 Reduction Catalyst. Same as in Method 25, Section 6.3.1.2.
6.2.3 Sample Injection System. Same as in Method 25, Section
6.3.1.4, equipped to accept a sample line from the Tedlar bag.
6.2.4 Flame Ionization Detector. Meeting the linearity
specifications of Section 10.3 and having a minimal instrument range of
10 to 1,000 ppm CO.
6.2.5 Data Recording System. Analog strip chart recorder or
digital integration system, compatible with the FID, for permanently
recording the analytical results.

7.0 Reagents and Standards

7.1 Sample Collection. Same as in Method 10A, Section 7.1.
7.2 Sample Analysis.
7.2.1 Carrier, Fuel, and Combustion Gases. Same as in Method 25,
Sections 7.2.1, 7.2.2, and 7.2.3, respectively.
7.2.2 Calibration Gases. Three standard gases with nominal CO
concentrations of 20, 200, and 1,000 ppm CO in nitrogen. The
calibration gases shall be certified by the manufacturer to be
2 percent of the specified concentrations.
7.2.3 Reduction Catalyst Efficiency Check Calibration Gas.
Standard CH4 gas with a nominal concentration of 1,000 ppm
in air.

8.0 Sample Collection, Preservation, Storage, and Transport

Same as in Method 10A, Section 8.0.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.0........................... Sample bag/ Ensures that negative
sampling system bias introduced
leak-checks. through leakage is
minimized.
10.1.......................... Carrier gas blank Ensures that positive
check. bias introduced by
contamination of
carrier gas is less
than 5 ppmv.
10.2.......................... Reduction Ensures that negative
catalyst bias introduced by
efficiency check. inefficient
reduction catalyst
is less than 5
percent.
10.3.......................... Analyzer Ensures linearity of
calibration. analyzer response to
standards.
11.2.......................... Triplicate sample Ensures precision of
analyses. analytical results.
------------------------------------------------------------------------

10.0 Calibration and Standardization

10.1 Carrier Gas Blank Check. Analyze each new tank of carrier gas
with the GC analyzer according to Section 11.2 to check for
contamination. The corresponding concentration must be less than 5 ppm
for the tank to be acceptable for use.
10.2 Reduction Catalyst Efficiency Check. Prior to initial use,
the reduction catalyst shall be tested for reduction efficiency. With
the heated reduction catalyst bypassed, make triplicate injections of
the 1,000 ppm CH4 gas (Section 7.2.3) to calibrate the
analyzer. Repeat the procedure using 1,000 ppm CO gas (Section 7.2.2)
with the catalyst in operation. The reduction catalyst operation is
acceptable if the CO response is within 5 percent of the certified gas
value.
10.3 Analyzer Calibration. Perform this test before the system is
first placed into operation. With the reduction catalyst in operation,
conduct a linearity check of the analyzer using the standards specified
in Section 7.2.2. Make triplicate injections of each calibration gas,
and then calculate the average response factor (area/ppm) for each gas,
as well as the overall mean of the response factor values. The
instrument linearity is acceptable if the average response factor of
each calibration gas is within 2.5 percent of the overall mean value
and if the relative standard deviation (calculated in Section 12.8 of
Method 25) for each set of triplicate injections is less than 2
percent. Record the overall mean of the response factor values as the
calibration response factor (R).

11.0 Analytical Procedure

11.1 Preparation for Analysis. Before putting the GC analyzer into
routine operation, conduct the calibration procedures listed in Section
10.0. Establish an appropriate carrier flow rate and detector
temperature for the specific instrument used.
11.2 Sample Analysis. Purge the sample loop with sample, and then
inject the sample. Analyze each sample in triplicate, and calculate the
average sample area (A). Determine the bag CO concentration according
to Section 12.2.

12.0 Calculations and Data Analysis

Carry out calculations retaining at least one extra significant
figure beyond that of the acquired data. Round off results only after
the final calculation.
12.1 Nomenclature.

A = Average sample area.
Bw = Moisture content in the bag sample, fraction.
C = CO concentration in the stack gas, dry basis, ppm.
Cb = CO concentration in the bag sample, dry basis, ppm.
F = Volume fraction of CO2 in the stack, fraction.
Pbar = Barometric pressure, mm Hg.
Pw = Vapor pressure of the H2O in the bag (from
Table 10A-2, Method 10A), mm Hg.
R = Mean calibration response factor, area/ppm.

12.2 CO Concentration in the Bag. Calculate Cb using
Equations 10B-1 and 10B-2. If condensate is visible in the Tedlar bag,
calculate Bw using Table 10A-2 of Method 10A and the
temperature and barometric pressure in the analysis room. If condensate
is not visible, calculate Bw using the

[[Page 61937]]

temperature and barometric pressure at the sampling site.
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12.3 CO Concentration in the Stack
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13.0 Method Performance. [Reserved]

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

Same as in Method 25, Section 16.0, with the addition of the
following:

1. Butler, F.E, J.E. Knoll, and M.R. Midgett. Development and
Evaluation of Methods for Determining Carbon Monoxide Emissions.
Quality Assurance Division, Environmental Monitoring Systems
Laboratory, U.S. Environmental Protection Agency, Research Triangle
Park, NC. June 1985. 33 pp.

17.0 Tables, Diagrams, Flowcharts, and Validation Data. [Reserved]

Method 11--Determination of Hydrogen Sulfide Content of Fuel Gas
Streams in Petroleum Refineries

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Hydrogen sulfide (H2S)........... 7783-06-4 8 mg/m\3\--740 mg/
m\3\, (6 ppm--520
ppm).
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of the H2S content of fuel gas streams at petroleum
refineries.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 A sample is extracted from a source and passed through a
series of midget impingers containing a cadmium sulfate
(CdSO4) solution; H2S is absorbed, forming
cadmium sulfide (CdS). The latter compound is then measured
iodometrically.

3.0 Definitions. [Reserved]

[[Page 61938]]

4.0 Interferences

4.1 Any compound that reduces iodine (I2) or oxidizes
the iodide ion will interfere in this procedure, provided it is
collected in the CdSO4 impingers. Sulfur dioxide in
concentrations of up to 2,600 mg/m\3\ is removed with an impinger
containing a hydrogen peroxide (H2O2) solution.
Thiols precipitate with H2S. In the absence of
H2S, only traces of thiols are collected. When methane-and
ethane-thiols at a total level of 300 mg/m\3\ are present in addition
to H2S, the results vary from 2 percent low at an
H2S concentration of 400 mg/m\3\ to 14 percent high at an
H2S concentration of 100 mg/m\3\. Carbonyl sulfide at a
concentration of 20 percent does not interfere. Certain carbonyl-
containing compounds react with iodine and produce recurring end
points. However, acetaldehyde and acetone at concentrations of 1 and 3
percent, respectively, do not interfere.
4.2 Entrained H2O2 produces a negative
interference equivalent to 100 percent of that of an equimolar quantity
of H2S. Avoid the ejection of H2O2
into the CdSO4 impingers.

5.0 Safety

5.1 Disclaimer. This method may involve hazardous materials,
operations, and equipment. This test method may not address all of the
safety problems associated with its use. It is the responsibility of
the user of this test method to establish appropriate safety and health
practices and determine the applicability of regulatory limitations
prior to performing this test method.
5.2 Corrosive reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water for at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burns as thermal
burns.
5.2.1 Hydrogen Peroxide. Irritating to eyes, skin, nose, and
lungs. 30% H2O2 is a strong oxidizing agent.
Avoid contact with skin, eyes, and combustible material. Wear gloves
when handling.
5.2.2 Hydrochloric Acid. Highly toxic. Vapors are highly
irritating to eyes, skin, nose, and lungs, causing severe damage. May
cause bronchitis, pneumonia, or edema of lungs. Exposure to
concentrations of 0.13 to 0.2 percent can be lethal in minutes. Will
react with metals, producing hydrogen.

6.0 Equipment and Supplies

6.1 Sample Collection. The following items are needed for sample
collection:
6.1.1 Sampling Line. Teflon tubing, 6- to 7- mm (\1/4\-in.) ID, to
connect the sampling train to the sampling valve.
6.1.2 Impingers. Five midget impingers, each with 30-ml capacity.
The internal diameter of the impinger tip must be 1 mm
0.05 mm. The impinger tip must be positioned 4 to 6 mm from the bottom
of the impinger.
6.1.3 Tubing. Glass or Teflon connecting tubing for the impingers.
6.1.4 Ice Water Bath. To maintain absorbing solution at a low
temperature.
6.1.5 Drying Tube. Tube packed with 6- to 16- mesh indicating-type
silica gel, or equivalent, to dry the gas sample and protect the meter
and pump. If the silica gel has been used previously, dry at 175 deg.C
(350 deg.F) for 2 hours. New silica gel may be used as received.
Alternatively, other types of desiccants (equivalent or better) may be
used, subject to approval of the Administrator.

Note: Do not use more than 30 g of silica gel. Silica gel
adsorbs gases such as propane from the fuel gas stream, and use of
excessive amounts of silica gel could result in errors in the
determination of sample volume.

6.1.6 Sampling Valve. Needle valve, or equivalent, to adjust gas
flow rate. Stainless steel or other corrosion-resistant material.
6.1.7 Volume Meter. Dry gas meter (DGM), sufficiently accurate to
measure the sample volume within 2 percent, calibrated at the selected
flow rate (about 1.0 liter/min) and conditions actually encountered
during sampling. The meter shall be equipped with a temperature sensor
(dial thermometer or equivalent) capable of measuring temperature to
within 3 deg.C (5.4 deg.F). The gas meter should have a petcock, or
equivalent, on the outlet connector which can be closed during the
leak-check. Gas volume for one revolution of the meter must not be more
than 10 liters.
6.1.8 Rate Meter. Rotameter, or equivalent, to measure flow rates
in the range from 0.5 to 2 liters/min (1 to 4 ft\3\/hr).
6.1.9 Graduated Cylinder. 25-ml size.
6.1.10 Barometer. Mercury, aneroid, or other barometer capable of
measuring

[[Page 61939]]

atmospheric pressure to within 2.5 mm Hg (0.1 in. Hg). In many cases,
the barometric reading may be obtained from a nearby National Weather
Service station, in which case, the station value (which is the
absolute barometric pressure) shall be requested and an adjustment for
elevation differences between the weather station and the sampling
point shall be applied at a rate of minus 2.5 mm Hg (0.1 in Hg) per 30
m (100 ft) elevation increase or vice-versa for elevation decrease.
6.1.11 U-tube Manometer. 0-; to 30-cm water column, for leak-check
procedure.
6.1.12 Rubber Squeeze Bulb. To pressurize train for leak-check.
6.1.13 Tee, Pinchclamp, and Connecting Tubing. For leak-check.
6.1.14 Pump. Diaphragm pump, or equivalent. Insert a small surge
tank between the pump and rate meter to minimize the pulsation effect
of the diaphragm pump on the rate meter. The pump is used for the air
purge at the end of the sample run; the pump is not ordinarily used
during sampling, because fuel gas streams are usually sufficiently
pressurized to force sample gas through the train at the required flow
rate. The pump need not be leak-free unless it is used for sampling.
6.1.15 Needle Valve or Critical Orifice. To set air purge flow to
1 liter/min.
6.1.16 Tube Packed with Active Carbon. To filter air during purge.
6.1.17 Volumetric Flask. One 1000-ml.
6.1.18 Volumetric Pipette. One 15-ml.
6.1.19 Pressure-Reduction Regulator. Depending on the sampling
stream pressure, a pressure-reduction regulator may be needed to reduce
the pressure of the gas stream entering the Teflon sample line to a
safe level.
6.1.20 Cold Trap. If condensed water or amine is present in the
sample stream, a corrosion-resistant cold trap shall be used
immediately after the sample tap. The trap shall not be operated below
0 deg.C (32 deg.F) to avoid condensation of C3 or
C4 hydrocarbons.
6.2 Sample Recovery. The following items are needed for sample
recovery:
6.2.1 Sample Container. Iodine flask, glass-stoppered, 500-ml
size.
6.2.2 Volumetric Pipette. One 50-ml.
6.2.3 Graduated Cylinders. One each 25- and 250-ml.
6.2.4 Erlenmeyer Flasks. 125-ml.
6.2.5 Wash Bottle.
6.2.6 Volumetric Flasks. Three 1000-ml.
6.3 Sample Analysis. The following items are needed for sample
analysis:
6.3.1 Flask. Glass-stoppered iodine flask, 500-ml.
6.3.2 Burette. 50-ml.
6.3.3 Erlenmeyer Flask. 125-ml.
6.3.4 Volumetric Pipettes. One 25-ml; two each 50- and 100-ml.
6.3.5 Volumetric Flasks. One 1000-ml; two 500-ml.
6.3.6 Graduated Cylinders. One each 10- and 100-ml.

7.0 Reagents and Standards

7.1 Sample Collection. The following reagents are required for
sample collection:
7.1.1 CdSO4 Absorbing Solution. Dissolve 41 g of
3CdSO48H2O and 15 ml of 0.1 M sulfuric acid in a
1-liter volumetric flask that contains approximately \3/4\ liter of
water. Dilute to volume with deionized, distilled water. Mix
thoroughly. The pH should be 3 0.1. Add 10 drops of Dow-
Corning Antifoam B. Shake well before use. This solution is stable for
at least one month. If Antifoam B is not used, a more labor-intensive
sample recovery procedure is required (see Section 11.2).
7.1.2 Hydrogen Peroxide, 3 Percent. Dilute 30 percent
H2O2 to 3 percent as needed. Prepare fresh daily.
7.1.3 Water. Deionized distilled to conform to ASTM D 1193-77 or
91, Type 3 (incorporated by reference--see Sec. 60.17). The
KMnO4 test for oxidizable organic matter may be omitted when
high concentrations of organic matter are not expected to be present.
7.2 Sample Recovery. The following reagents are needed for sample
recovery:
7.2.1 Water. Same as Section 7.1.3.
7.2.2 Hydrochloric Acid (HCl) Solution, 3 M. Add 240 ml of
concentrated HCl (specific gravity 1.19) to 500 ml of water in a 1-
liter volumetric flask. Dilute to 1 liter with water. Mix thoroughly.
7.2.3 Iodine (I2) Solution, 0.1 N. Dissolve 24 g of
potassium iodide (KI) in 30 ml of water. Add 12.7 g of resublimed
iodine (I2) to the KI solution. Shake the mixture until the
I2 is completely dissolved. If possible, let the solution
stand overnight in the dark. Slowly dilute the solution to 1 liter with
water, with swirling. Filter the solution if it is cloudy. Store
solution in a brown-glass reagent bottle.
7.2.4 Standard I2 Solution, 0.01 N. Pipette 100.0 ml of
the 0.1 N iodine solution into a 1-liter volumetric flask, and dilute
to volume with water. Standardize daily as in Section 10.2.1. This
solution must be protected from light. Reagent bottles and flasks must
be kept tightly stoppered.
7.3 Sample Analysis. The following reagents and standards are
needed for sample analysis:
7.3.1 Water. Same as in Section 7.1.3.
7.3.2 Standard Sodium Thiosulfate Solution, 0.1 N. Dissolve 24.8 g
of sodium thiosulfate pentahydrate
(Na2S2O35H2O) or
15.8 g of anhydrous sodium thiosulfate
(Na2S2O3) in 1 liter of water, and add
0.01 g of anhydrous sodium carbonate (Na2CO3) and
0.4 ml of chloroform (CHCl3) to stabilize. Mix thoroughly by
shaking or by aerating with nitrogen for approximately 15 minutes, and
store in a glass-stoppered, reagent bottle. Standardize as in Section
10.2.2.
7.3.3 Standard Sodium Thiosulfate Solution, 0.01 N. Pipette 50.0
ml of the standard 0.1 N Na2S2O3
solution into a volumetric flask, and dilute to 500 ml with water.

Note: A 0.01 N phenylarsine oxide
(C6H5AsO) solution may be prepared instead of
0.01 N Na2S2O3 (see Section 7.3.4).

7.3.4 Standard Phenylarsine Oxide Solution, 0.01 N. Dissolve 1.80
g of (C6H5AsO) in 150 ml of 0.3 N sodium
hydroxide. After settling, decant 140 ml of this solution into 800 ml
of water. Bring the solution to pH 6-7 with 6 N HCl, and dilute to 1
liter with water. Standardize as in Section 10.2.3.
7.3.5 Starch Indicator Solution. Suspend 10 g of soluble starch in
100 ml of water, and add 15 g of potassium hydroxide (KOH) pellets.
Stir until dissolved, dilute with 900 ml of water, and let stand for 1
hour. Neutralize the alkali with concentrated HCl, using an indicator
paper similar to Alkacid test ribbon, then add 2 ml of glacial acetic
acid as a preservative.

Note: Test starch indicator solution for decomposition by
titrating with 0.01 N I2 solution, 4 ml of starch
solution in 200 ml of water that contains 1 g of KI. If more than 4
drops of the 0.01 N I2 solution are required to obtain
the blue color, a fresh solution must be prepared.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Sampling Train Preparation. Assemble the sampling train as
shown in Figure 11-1, connecting the five midget impingers in series.
Place 15 ml of 3 percent H2O2 solution in the
first impinger. Leave the second impinger empty. Place 15 ml of the
CdSO4 solution in the third, fourth, and fifth impingers.
Place the impinger assembly in an ice water bath container, and place
water and crushed ice around the impingers. Add more ice during the
run, if needed.

[[Page 61940]]

8.2 Leak-Check Procedure.
8.2.1 Connect the rubber bulb and manometer to the first impinger,
as shown in Figure 11-1. Close the petcock on the DGM outlet.
Pressurize the train to 25 cm water with the bulb, and close off the
tubing connected to the rubber bulb. The train must hold 25 cm water
pressure with not more than a 1 cm drop in pressure in a 1-minute
interval. Stopcock grease is acceptable for sealing ground glass
joints.
8.2.2 If the pump is used for sampling, it is recommended, but not
required, that the pump be leak-checked separately, either prior to or
after the sampling run. To leak-check the pump, proceed as follows:
Disconnect the drying tube from the impinger assembly. Place a vacuum
gauge at the inlet to either the drying tube or the pump, pull a vacuum
of 250 mm Hg (10 in. Hg), plug or pinch off the outlet of the flow
meter, and then turn off the pump. The vacuum should remain stable for
at least 30 seconds. If performed prior to the sampling run, the pump
leak-check should precede the leak-check of the sampling train
described immediately above; if performed after the sampling run, the
pump leak-check should follow the sampling train leak-check.
8.3 Purge the connecting line between the sampling valve and the
first impinger by disconnecting the line from the first impinger,
opening the sampling valve, and allowing process gas to flow through
the line for one to two minutes. Then, close the sampling valve, and
reconnect the line to the impinger train. Open the petcock on the dry
gas meter outlet. Record the initial DGM reading.
8.4 Open the sampling valve, and then adjust the valve to obtain a
rate of approximately 1 liter/min (0.035 cfm). Maintain a constant
(10 percent) flow rate during the test. Record the DGM
temperature.
8.5 Sample for at least 10 minutes. At the end of the sampling
time, close the sampling valve, and record the final volume and
temperature readings. Conduct a leak-check as described in Section 8.2
above.
8.6 Disconnect the impinger train from the sampling line. Connect
the charcoal tube and the pump as shown in Figure 11-1. Purge the train
[at a rate of 1 liter/min (0.035 ft\3\/min)] with clean ambient air for
15 minutes to ensure that all H2S is removed from the
H2O2. For sample recovery, cap the open ends, and
remove the impinger train to a clean area that is away from sources of
heat. The area should be well lighted, but not exposed to direct
sunlight.
8.7 Sample Recovery.
8.7.1 Discard the contents of the H2O2
impinger. Carefully rinse with water the contents of the third, fourth,
and fifth impingers into a 500-ml iodine flask.

Note: The impingers normally have only a thin film of CdS
remaining after a water rinse. If Antifoam B was not used or if
significant quantities of yellow CdS remain in the impingers, the
alternative recovery procedure in Section 11.2 must be used.

8.7.2 Proceed to Section 11 for the analysis.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.2, 10.1..................... Sampling Ensure accurate
equipment leak- measurement of
check and sample volume.
calibration.
11.2.......................... Replicate Ensure precision of
titrations of titration
blanks. determinations.
------------------------------------------------------------------------

10.0 Calibration and Standardization

Note: Maintain a log of all calibrations.

10.1 Calibration. Calibrate the sample collection equipment as
follows.
10.1.1 Dry Gas Meter.
10.1.1.1 Initial Calibration. The DGM shall be calibrated before
its initial use in the field. Proceed as follows: First, assemble the
following components in series: Drying tube, needle valve, pump,
rotameter, and DGM. Then, leak-check the metering system as follows:
Place a vacuum gauge (at least 760 mm Hg) at the inlet to the drying
tube, and pull a vacuum of 250 mm Hg (10 in. Hg); plug or pinch off the
outlet of the flow meter, and then turn off the pump. The vacuum shall
remain stable for at least 30 seconds. Carefully release the vacuum
gauge before releasing the flow meter end. Next, calibrate the DGM (at
the sampling flow rate specified by the method) as follows: Connect an
appropriately sized wet-test meter (e.g., 1 liter per revolution) to
the inlet of the drying tube. Make three independent calibration runs,
using at least five revolutions of the DGM per run. Calculate the
calibration factor, Y (wet-test meter calibration volume divided by the
DGM volume, both volumes adjusted to the same reference temperature and
pressure), for each run, and average the results. If any Y value
deviates by more than 2 percent from the average, the DGM is
unacceptable for use. Otherwise, use the average as the calibration
factor for subsequent test runs.
10.1.1.2 Post-Test Calibration Check. After each field test
series, conduct a calibration check as in Section 10.1.1.1, above,
except for the following two variations: (a) three or more revolutions
of the DGM may be used and (b) only two independent runs need be made.
If the calibration factor does not deviate by more than 5 percent from
the initial calibration factor (determined in Section 10.1.1.1), then
the DGM volumes obtained during the test series are acceptable. If the
calibration factor deviates by more than 5 percent, recalibrate the DGM
as in Section 10.1.1.1, and for the calculations, use the calibration
factor (initial or recalibration) that yields the lower gas volume for
each test run.
10.1.2 Temperature Sensors. Calibrate against mercury-in-glass
thermometers.
10.1.3 Rate Meter. The rate meter need not be calibrated, but
should be cleaned and maintained according to the manufacturer's
instructions.
10.1.4 Barometer. Calibrate against a mercury barometer.
10.2 Standardization.
10.2.1 Iodine Solution Standardization. Standardize the 0.01 N
I2 solution daily as follows: Pipette 25 ml of the
I2 solution into a 125-ml Erlenmeyer flask. Add 2 ml of 3 M
HCl. Titrate rapidly with standard 0.01 N
Na2S2O3 solution or with 0.01 N
C6H5AsO until the solution is light yellow, using
gentle mixing. Add four drops of starch indicator solution, and
continue titrating slowly until the blue color just disappears. Record
the volume of Na2S2O3 solution used,
VSI, or the volume of C6H5AsO solution
used, VAI, in ml. Repeat until replicate values agree within
0.05 ml. Average the replicate titration values which agree within 0.05
ml, and calculate the exact normality of the I2 solution
using Equation 11-3. Repeat the standardization daily.
10.2.2 Sodium Thiosulfate Solution Standardization. Standardize
the 0.1 N Na2S2O3 solution as follows:
Oven-dry potassium dichromate
(K2Cr2O7) at 180 to 200 deg.C (360 to
390 deg.F). To the nearest milligram, weigh 2 g of the dichromate (W).
Transfer the dichromate to a 500-ml volumetric flask, dissolve in
water, and dilute to exactly 500 ml. In a 500-ml iodine flask, dissolve
approximately 3 g of KI in 45 ml of water, then add 10 ml of 3 M HCl
solution. Pipette 50

[[Page 61941]]

ml of the dichromate solution into this mixture. Gently swirl the
contents of the flask once, and allow it to stand in the dark for 5
minutes. Dilute the solution with 100 to 200 ml of water, washing down
the sides of the flask with part of the water. Titrate with 0.1 N
Na2S2O3 until the solution is light
yellow. Add 4 ml of starch indicator and continue titrating slowly to a
green end point. Record the volume of
Na2S2O3 solution used, VS,
in ml. Repeat until replicate values agree within 0.05 ml. Calculate
the normality using Equation 11-1. Repeat the standardization each week
or after each test series, whichever time is shorter.
10.2.3 Phenylarsine Oxide Solution Standardization. Standardize
the 0.01 N C6H5AsO (if applicable) as follows:
Oven-dry K2Cr2O7 at 180 to 200 deg.C
(360 to 390 deg.F). To the nearest milligram, weigh 2 g of the
dichromate (W). Transfer the dichromate to a 500-ml volumetric flask,
dissolve in water, and dilute to exactly 500 ml. In a 500-ml iodine
flask, dissolve approximately 0.3 g of KI in 45 ml of water, then add
10 ml of 3 M HCl. Pipette 5 ml of the dichromate solution into the
iodine flask. Gently swirl the contents of the flask once, and allow it
to stand in the dark for 5 minutes. Dilute the solution with 100 to 200
ml of water, washing down the sides of the flask with part of the
water. Titrate with 0.01 N C6H5AsO until the
solution is light yellow. Add 4 ml of starch indicator, and continue
titrating slowly to a green end point. Record the volume of
C6H5AsO used, VA, in ml. Repeat until
replicate analyses agree within 0.05 ml. Calculate the normality using
Equation 11-2. Repeat the standardization each week or after each test
series, whichever time is shorter.

11.0 Analytical Procedure

Conduct the titration analyses in a clean area away from direct
sunlight.
11.1 Pipette exactly 50 ml of 0.01 N I2 solution into a
125-ml Erlenmeyer flask. Add 10 ml of 3 M HCl to the solution.
Quantitatively rinse the acidified I2 into the iodine flask.
Stopper the flask immediately, and shake briefly.
11.2 Use these alternative procedures if Antifoam B was not used
or if significant quantities of yellow CdS remain in the impingers.
Extract the remaining CdS from the third, fourth, and fifth impingers
using the acidified I2 solution. Immediately after pouring
the acidified I2 into an impinger, stopper it and shake for
a few moments, then transfer the liquid to the iodine flask. Do not
transfer any rinse portion from one impinger to another; transfer it
directly to the iodine flask. Once the acidified I2 solution
has been poured into any glassware containing CdS, the container must
be tightly stoppered at all times except when adding more solution, and
this must be done as quickly and carefully as possible. After adding
any acidified I2 solution to the iodine flask, allow a few
minutes for absorption of the H2S before adding any further
rinses. Repeat the I2 extraction until all CdS is removed
from the impingers. Extract that part of the connecting glassware that
contains visible CdS. Quantitatively rinse all the I2 from
the impingers, connectors, and the beaker into the iodine flask using
water. Stopper the flask and shake briefly.
11.3 Allow the iodine flask to stand about 30 minutes in the dark
for absorption of the H2S into the I2, then
complete the titration analysis as outlined in Sections 11.5 and 11.6.

Note: Iodine evaporates from acidified I2 solutions.
Samples to which acidified I2 has been added may not be
stored, but must be analyzed in the time schedule stated above.

11.4 Prepare a blank by adding 45 ml of CdSO4 absorbing
solution to an iodine flask. Pipette exactly 50 ml of 0.01 N
I2 solution into a 125-ml Erlenmeyer flask. Add 10 ml of 3 M
HCl. Stopper the flask, shake briefly, let stand 30 minutes in the
dark, and titrate with the samples.

Note: The blank must be handled by exactly the same procedure as
that used for the samples.

11.5 Using 0.01 N Na2S2O3
solution (or 0.01 N C6H5AsO, if applicable),
rapidly titrate each sample in an iodine flask using gentle mixing,
until solution is light yellow. Add 4 ml of starch indicator solution,
and continue titrating slowly until the blue color just disappears.
Record the volume of Na2S2O3 solution
used, VTT, or the volume of C6H5AsO
solution used, VAT, in ml.
11.6 Titrate the blanks in the same manner as the samples. Run
blanks each day until replicate values agree within 0.05 ml. Average
the replicate titration values which agree within 0.05 ml.

12.0 Data Analysis and Calculations

Carry out calculations, retaining at least one extra significant
figure beyond that of the acquired data. Round off figures only after
the final calculation.
12.1 Nomenclature.

CH2S = Concentration of H2S at standard
conditions, mg/dscm.
NA = Normality of standard C6H5AsO
solution, g-eq/liter.
NI = Normality of standard I2 solution, g-eq/
liter.
NS = Normality of standard (0.1 N)
Na2S2O3 solution, g-eq/liter.
NT = Normality of standard (0.01 N)
Na2S2O3 solution, assumed to be 0.1
NS, g-eq/liter.
Pbar = Barometric pressure at the sampling site, mm Hg.
Pstd = Standard absolute pressure, 760 mm Hg.
Tm = Average DGM temperature, deg.K.
Tstd = Standard absolute temperature, 293 deg.K.
VA = Volume of C6H5AsO solution used
for standardization, ml.
VAI = Volume of standard C6H5AsO
solution used for titration analysis, ml.
VI = Volume of standard I2 solution used for
standardization, ml.
VIT = Volume of standard I2 solution used for
titration analysis, normally 50 ml.
Vm = Volume of gas sample at meter conditions, liters.
Vm(std) = Volume of gas sample at standard conditions,
liters.
VSI = Volume of ``0.1 N
Na2S2O3 solution used for
standardization, ml.
VT = Volume of standard (0.01 N)
Na2S2O3 solution used in standardizing
iodine solution (see Section 10.2.1), ml.
VTT = Volume of standard (0.01 N)
Na2S2O3 solution used for titration
analysis, ml.
W = Weight of K2Cr2O7 used to
standardize Na2s2O3 or
C6H5AsO solutions, as applicable (see Sections
10.2.2 and 10.2.3), g.
Y = DGM calibration factor.

12.2 Normality of the Standard (0.1 N) Sodium
Thiosulfate Solution.
[GRAPHIC] [TIFF OMITTED] TR17OC00.238

Where:

2.039 = Conversion factor
= (6 g-eq I2/mole K2Cr2O7)
(1,000 ml/liter)/(294.2 g K2Cr2O7/
mole) (10 aliquot factor)

12.3 Normality of Standard Phenylarsine Oxide Solution (if
applicable).
[GRAPHIC] [TIFF OMITTED] TR17OC00.239

Where:

0.2039 = Conversion factor.
= (6 g-eq I2/mole K2Cr2O7)
(1,000 ml/liter)/(294.2 g K2Cr2O7/
mole) (100 aliquot factor)

12.4 Normality of Standard Iodine Solution.
[GRAPHIC] [TIFF OMITTED] TR17OC00.240

[[Page 61942]]

Note: If C6H5AsO is used instead of
Na2S2O3, replace NT and
VT in Equation 11-3 with NA and
VAS, respectively (see Sections 10.2.1 and 10.2.3).

12.5 Dry Gas Volume. Correct the sample volume measured by the DGM
to standard conditions (20 deg.C and 760 mm Hg).
[GRAPHIC] [TIFF OMITTED] TR17OC00.241

12.6 Concentration of H2S. Calculate the concentration
of H2S in the gas stream at standard conditions using
Equation 11-5:
[GRAPHIC] [TIFF OMITTED] TR17OC00.242

Where:

17.04 x 10\3\ = Conversion factor
= (34.07 g/mole H2S) (1,000 liters/m\3\) (1,000mg/g)/(1,000
ml/liter) (2H2S eq/mole)

Note: If C6H5AsO is used instead of
NaS22O3, replace NA and
VAT in Equation 11-5 with NA and
VAT, respectively (see Sections 11.5 and 10.2.3).

13.0 Method Performance

13.1 Precision. Collaborative testing has shown the intra-
laboratory precision to be 2.2 percent and the inter-laboratory
precision to be 5 percent.
13.2 Bias. The method bias was shown to be -4.8 percent when only
H2S was present. In the presence of the interferences cited
in Section 4.0, the bias was positive at low H2S
concentration and negative at higher concentrations. At 230 mg
H2S/m\3\, the level of the compliance standard, the bias was
+2.7 percent. Thiols had no effect on the precision.

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 References

1. Determination of Hydrogen Sulfide, Ammoniacal Cadmium
Chloride Method. API Method 772-54. In: Manual on Disposal of
Refinery Wastes, Vol. V: Sampling and Analysis of Waste Gases and
Particulate Matter. American Petroleum Institute, Washington, D.C.
1954.
2. Tentative Method of Determination of Hydrogen Sulfide and
Mercaptan Sulfur in Natural Gas. Natural Gas Processors Association,
Tulsa, OK. NGPA Publication No. 2265-65. 1965.
3. Knoll, J.D., and M.R. Midgett. Determination of Hydrogen
Sulfide in Refinery Fuel Gases. Environmental Monitoring Series,
Office of Research and Development, USEPA. Research Triangle Park,
NC 27711. EPA 600/4-77-007.
4. Scheil, G.W., and M.C. Sharp. Standardization of Method 11 at
a Petroleum Refinery. Midwest Research Institute Draft Report for
USEPA. Office of Research and Development. Research Triangle Park,
NC 27711. EPA Contract No. 68-02-1098. August 1976. EPA 600/4-77-
088a (Volume 1) and EPA 600/4-77-088b (Volume 2).
BILLING CODE 6560-50-P

[[Continued on page 61943]]

Notices For
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994

[[pp. 61893-61942]] Amendments for Testing and Monitoring Provisions

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