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R9 Laboratory SOP 531
ANALYSIS OF PERCHLORATE BY ION CHROMATOGRAPHY
Summary
This method covers the determination of perchlorate in reagent water, surface water, ground water, and drinking water using ion chromatography following EPA Method 314.0, "Determination of Perchlorate in Drinking Water Using Ion Chromatography", Rev. 1.0, November 1999. Although not specifically tested, this method is potentially applicable to mixed domestic water and industrial wastewaters.
The Region 9 Laboratory quantitation limit (QL) for perchlorate is 5.0 μg/L. A 1.0 mL volume of sample is injected onto and passed through a series of ion-exchange columns. The perchlorate anion is separated on the basis of its relative affinity to a low capacity, strongly basic anion exchanger. The separated perchlorate anion is directed into a strongly acidic cation suppressor exchanger where it is converted to the highly conductive acid form. The sodium hydroxide eluent is converted to weakly conductive acid. The separated anion in its acid form is detected by electrical conductivity and is determined on the basis of retention time as compared to the external standards. Quantitation is based on peak areas and a quad calibration curve is used to determine concentrations in environmental samples.