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The goal of this research was to develop a U.S. Environmental Protection Agency method for the determination sub-ppbconcentrations of the perchlorate anion (ClOsub4/sub sup-/sup) in drinking waters and in waters high in totaldissolved solids. To date, ion chromatography using a KOH mobile phase, electrolyticconductivity suppression (Dionex Corporation, Sunnyvale, CA) and electrospray ionization massspectrometric detection (ThermoFinnigan, San Jose, CA) has been explored with the followingsalient features:low-level linear calibration from 0.01 - 1.0 ppb with an Rsup2/sup 0.999;method detection limits (MDLs) in deionized and high ionic waters (up to 1000 ppmcommon anions sulfate, chloride and carbonate) from 0.03 - 0.11 ppb with no significantdifference between MDLs when using mass 99 or mass 101 as quantitation ions at =0.01;precision of replicate injections at 1 ppb was less than 5% relative standard deviation onmasses 99 and 101 on a daily basis;accuracy as determined by analysis of a certified reference material was 5% of certifiedvalue in deionized water; and,ruggedness as determined by the reproducibility of area counts of 1.0 ppb check standardsanalyzed periodically over a day of continuous analysis of high ionic matrices revealedsome deterioration of signal intensity (~15% drop). Simple measures were implemented topreserve signal intensity over time and in high ionic matrices. Includes 2 references.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 4 File Size: 1 file , 290 KB