Determination of Total Iodine in Dairy Products by Inductively Coupled Plasma/Mass Spectrometry with Microwave Digestion

A method for the determination of total iodine by microwave digested-inductively coupled plasma mass spectrometry (ICP-MS) in infant formula using nitric acid as the digestion medium and Pr as the internal standard is developed. The detection limit of the method was 0.02 μg/kg, while the linear range was 0~100 μg/L and the linear coefficient was better than 0.999 5. The precision of the method (RSD %) was less than 5.0%. Precision and accuracy are evaluated by the analysis of certified reference materials GBW10017 milk powder. The determined iodine contents were in good agreement with the certified values. The spiked recoveries of real samples were from 94.1% to 97.7%. The experiments show that this method is sensitive, simple, rapid, and accurate for the determination of iodine contents in dairy products.