An improved ion chromatography method for determination of trace level perchlorate in environmental water

An improved ion chromatography( IC) method was developed to determine trace level perchlorate in environmental water samples by using hydroxide selective column lonPac AS16. Perchorate was separated with NaOH eluent added organic modifier. To eliminate the coelution of perchlorate and 4-chlorobenzene sulfonate(4-CBS), organic solvents as the modifier was added into the eluent. The effects of four kinds of organic solvents on the retention time of perchlorate and 4-CBS were studied, and acetonitrile was selected. To improve the method sensitivity, the concentrator column(AG19) was used to concentrate perchlorate online in this work. With the adoption of. preconcentration technique, the sensitivity of this method was improved obviously and the method detection limit ( MDL) is 0.1 mu g/L. The linear range is 0.2-200 mu g/L with a linear correlation coefficient of 0.9989, and the relative standard deviation( RSD) of peak area for the eleven successive injections of 0.5 mu g/L perchlorate is 4.2%. The method was applied to the determination of perchlorate in some real environmental water samples and the spiked recoveries were in the range of 93 % - 113%.