Improved method for the determination of trace perchlorate in ground and drinking waters by ion chromatography

Ammonium perchlorate, a key ingredient in solid rocket propellants, has bee n found in ground and surface waters in a number of U.S. states, and perchl orate contamination of public drinking water wells is now a serious problem in California. Perchlorate poses a health risk and preliminary data from t he U.S. EPA reports that exposure to less than 4-18 mu g/l provides adequat e human health protection. An improved ion chromatographic method was devel oped for the determination of low mu g/l levels of perchlorate in ground an d drinking waters based on a Dionex IonPac AS16 column, an hydroxide eluent generated using an EG40 automated eluent generator, large loop (1000 mu l) injection, and suppressed conductivity detection. The method is free of in terferences from common inorganic anions, linear over the range of 2-100 mu g/l perchlorate, and quantitative recoveries are obtained for low mu g/l l evels of perchlorate in spiked ground and drinking water samples. The MDL o f 150 ng/l permits quantification of perchlorate below the levels that ensu re adequate health protection. (C) 2000 Elsevier Science B.V. All rights re served.