Comparison of detemination methods of trace Iodine in infant formula powder

Gas chromatography( GC),inductively coupled plasma-mass spectrometry( ICP-MS) and ion chromatography( IC) were used to determine iodine in infant formula powder. Comparing various factors:pretreatment method,iodine types,linear range and recovery,detection limit,precision,etc.Pretreatment of ICPMS method was simple,the interference of complex matrix was minimum,the linear range between 1g/L to 50μg /L,correlation coefficient could reach more than 0.999,recovery rate was between 95.9% ~103.7%,RSD was 0.6% ~2.2%,the detection limit was 0.6μg /100 g.In conclusion,coupled plasma mass spectrometry was more suitable for iodine determination of infant formula milk powder in laboratory routine analysis.