ION CHROMATOGRAPHIC DETERMINATION OF LOW- LEVEL PERCHLORATE IN NATURAL WATERS

摘要

Perchlorate (ClO_4~-) is a persistent contaminant of drinking-, surface-, and ground- water, and of soils. Possible contributors of ClO_4~- contamination are the military, the space program, and supporting industries, and fertilizers. Perchlorate has long been known to have a negative effect on the thyroid gland. It has been added to the United States Environmental Protection Agency's (EPA) Contaminant Candidate List (CCL) in 1998, so that ClO_4~- can be regulated at a concentration safe to humans. This paper describes the determination of trace level ClO_4~- in various matrices utilizing ion chromatographic method. The method utilizes a Dionex IonPac AS11 column with suppressed conductivity detection, 1500 μl sample loop, and a 100 mM NaOH eluent at a flow rate of 1.0 ml/min. These parameters allow a method detection limit (MDL) of 0.277 μg/l and a short retention time of ～ 8 minutes. A quality control, proficiency testing sample from the EPA and a number of environmental samples from New York State (ground water) and California (ground and surface waters) were analyzed by this technique. Concentrations measured were in the range of 1.9-217 μg/l. No evidence of ClO_4~- was found in various commonly used fertilizers.