Simultaneous Determination of Chlorite, Chlorate and Perchlorate in Drinking Water by Ion Chromatography

A method for simultaneous determination of chlorite, chlorate and perchlorate in drinking water was established by ion chromatography. The sample was filtered by 0.22μm qeuosystem filter membrane, and then introduced into ion chromatography with sample injection of 500μL. IonPac AS20 anion exchange column was used for separation with KOH solution for online gradient elution, and electrolytic conductivity detector was used for determination. The results showed that linearity ranges of chlorite, chlorate and perchlorate were found in the same range of 0.005-0.750 mg·L^-1, with detection limits (3S/N) of 0.78, 0.56, 1.50μg·L^-1. Test for recorery was made by standard addition method on the actual water samples at three concentration levels, giving recoveries in the ranges of 88.0%-104%, 89.0%-97.4%, 89.2%-94.9%, and RSDs (n=6) of the determined values were all less than 2.0%. The proposed method was used for the analysis of 36 samples composed of 12 tap water, 12 bottled water and 12 well water, and the average detection rates of chlorite, chlorate and perchlorate were 22.2%, 55.6%, 38.9%, with their residual values all less than the standard limits (0.7, 0.7, 0.07 mg·L^-1).