Determination of micro amounts of iodide in dairy products by ion chromatography with direct amperometric detector

A method was developed for the determination of micro amounts of iodide in dairy products by ion chromatography with direct amperometric detection The eluent used was 0 04 mol/L NaOH The relative standard deviations of retention times and peak heights for 1 mg/L and 2 μg/L iodide solutions were 0 67%,3 9% (n=8) and 0 97%,1 8% (n=8) ,respectively Calibration curves showed good linearity with r = 0 999 1 (n=8, from 10 μg/L to 160 μg/L),and with r = 0 998 6 (n=8, from 400 μg/L to 5 mg/L) The detection limit of iodide by this method was 1 μg/L The method has been used to analyse two kinds of milk powder and a kind of fresh milk. The recoveries were 89 0%,86 0% and 84 1% for infant formula milk powder, mother's milk powder and fresh milk, respectively.