Abstract:An ion chromatographic method was developed for the determination of perchlorate in milk powder. Sample was first extracted by acetonitrile under basic condition, then purified on an RP column after concentration and filtration, and finally separated on an AS20 column (150 mm×4.0 mm) with the eluent of 30～70 mmol/L NaOH solution at the flow rate of 1.0 mL/min. Perchlorate concentration with conductivity showed good linearity in the range from 0.4 to 20 μg/L, with the correlation coefficient of 0.999,8. The rate of recovery ranged from 77.2% to 108%, and limit of detection was 20 μg/kg. The method had been applied to determine perchlorate content in 41 milk powders and the detection rate of 31.7% was achieved.