|
Status of Inter-Laboratory Study
DAVID T. TSUI, USAF, Capt
ARFL/HEST, Bldg 79
2856 G Street
Wright-Patterson AFB, OH 45433
(P) 937-255-5150 x 3183
(F) 937-255-1474
AS-11 Users
| Air Force Research Lab * |
Clayton Laboratories* |
Metropolitan Water District
of Southern California * |
Thiokol * |
| Orange County Water District* |
UDOH - DELS * |
| Montgomery Watson Labs * |
Topics
- Status of Inter-Laboratory Collaborative Study
- Stability Study
- Container Type and TDS
- pH
- Light and Temperature
- Emerging Issues
- Alternative Methodologies
- Sample Prep Procedures for Waste Water and Biological Matrices
- Effects of Organic Solvent on Method Performance
- Effects of Cations on Method Performance
- Standard IC Method for Perchlorate Analysis
Method Detection Limit (MDL) - The lowest concentration of a
substance which can be measured with 99 percent confidence that the analyte
concentration is greater than zero.
Two Ways of Calculating MDL:
-
EPA's Guidelines
MDL = student t-Value x (STDD/M)
Provided that S/N is greater than 3
-
Statistical Calculation
Plot Concentration vs. % CV
MDL is the concentration at 10% CV
Provided that S/N > 3
Practical Quantitation Limit (PQL) - PQL is usually set between 5 to
10 times MDL.
Reporting Limit (RL) - Minimum quantifiable level that may
be reported per regulatory purpose. It is Typically set between 5 to 10 times
MDL for regulated compounds.
Minimum Reporting Limit (MRL) - Same as RL.
Collaborative-Laboratory Study (Col-Lab1)
- All-inclusive Policy, however,. Equipment, Analyst, and Method
- 21 Laboratory Participants
- Designed to Study AS-11 and CDHS Methods Performance
- Also Incorporates the Following Tasks to Examine Other Analytical Issues
- Task 1. Methods Validation Study (On-Going)
- Task 2. Holding Time Study
- Sub-Task A. Container Type/TDS (On-Going)
- Sub-Task B. pH (On-Going)
- Sub-Task C. Light, Temperature, Humidity (Complete)
- Task 3. Anion Specific Influence
- CDHS (Complete)
- AS-11 Methods (On-Going)
21 Laboratory Participants
Advanced Technology Laboratories
Aerojet
Air Force Research Lab - Environics Lab. *
Air Force Research Lab - Toxicology Laboratoy
Alliant Technology Systems
Alpha Analytical
Agricultural Priority Pollutant Laboratory, Inc.
AMPAC
California DHS- Berkley
California DHS-Los Angeles
California Laboratory Services
Clayton Laboratories, Inc. *
Clinical Laboratory of San Bernardino, Inc.
Columbia Analytical Services, Inc.
Dionex Corp. *
E. S. Babcock and Sons, Inc.
LA Agricultural Commission - Environmental Toxicology Lab
Metropolitan Water District of Southern California *
Montgomery Watson Labs *
Thiokol *
Utah Department of Health - Department ELS *
Weck Laboratories, Inc.
* AS-11 users
Task 1. Methods Validation Study
Purpose: Measure the performance of ion chromatographic methods for
the analysis of perchlorate in drinking and groundwater samples. Method
performance will be evaluated based on uncertainty (precision) and bias
(accuracy)) and measured with respect to perchlorate concentration and total
dissolved solids(TDS).
Study Coordinator: Steve Pia
Study Parameters
| Effects of TDS: |
Three TDS Levels to be determined at the
beginning of the study |
| Concentration
Dependence: |
Four Levels of perchlorate concentration
will be verified during the beginning of the study. |
| Analytical Methods: |
CDHS and AS-11 |
Target Groups:
21 Participating Laboratories
QA/QC
| Sample Preparation/Shipping: |
NERL |
| TDS measurements: |
UDOH/DELS or MPWD |
| PH: |
UDOH/DELS |
| EPA 300: |
APPL, OCWD or UDOH/DELS |
| Concentration Verification: |
3 of 21 Col-Labs |
| Concentration Determination: |
3 of 21 Col-Labs |
Milestones
| Laboratory Selection: |
1 May 98 (On Time) |
| Sample Prep/Shipment: |
8 May 98 (Delayed) |
| Laboratory Analysis: |
8 Jun 98 (Delayed) |
| Lab Results Due: |
8-15 Jun 98 (?) |
| Draft Report Due: |
8 July 98 (?) |
| Final Peer-Reviewed Report Due: |
? Aug 98 |
Task 2. Holding Time Study
Sub-Task A. Total Dissolve Solids (TDS) and Container Type
Purpose: Evaluate and assess the stability of perchlorate with
respect to TDS and container types. This study will be incorporated into Task
1. Perchlorate concentration determination with respect to container type
(glass vs. plastic) and TDS will be measured at fixed interval beyond the
initial concentration verification as stated in Task 1.
Study Coordinator: Steve Pia
Study Parameters
Same as Task 1, except container type is added as a
parameter
| Effects of TDS: |
Three TDS Levels |
| Concentration Dependence: |
Four Levels |
| Analytical Methods: |
CA-DHS and AS-11 |
| Bottle Types: |
Glass vs. Polyethylene |
Target Groups:
Concentration determination conducted by three of the 21 Laboratories on a
weekly basis.
QA/QC
| Sample Preparation/Shipping: |
NERL |
| TDS measurements: |
Measured as part of Task 1 |
| PH: |
Measured as part of Task 1 |
| EPA 300: |
APPL, OCWD or UDOH/DELS |
| Concentration Determination: |
Beyond the initial concentration verification, 3 of 21
Col-Labs will continue to measure perchlorate concentration in the Col-Lab 1
samples for 3 months on a weekly basis |
Milestones
| Laboratory Selection: |
1 May 98 (On Time) |
| Sample Prep/Shipment: |
8 May 98 (Delayed) |
| Laboratory Analysis: |
8-15 Oct 98 (Delayed) |
| Lab Results Due: |
8-15 Oct 98 (?) |
| Draft Report Due: |
8-15 Nov 98 (?) |
| Final Peer-Reviewed Report Due: |
? Dec 98 |
Task 2. Holding Time Study
Sub-Task B. pH
Purpose: Evaluate and assess the stability of perchlorate with
respect to pH.
Study Coordinator: Dr. Sanwat Chaduri, UDOH/DELS
Study Parameters: pH 5.5-8.5
QA/QC: Concentration Verification: UDOH/DELS
Milestone(s): TBD
|
