Determination of Total Iodine in Foods and Dietary Supplements Using Inductively Coupled Plasma–Mass Spectrometry

Abstract

Abstract A method was developed and validated for the determination of total iodine in a wide variety of food products and dietary supplements. The method involves a unique sample digestion with a KOH solution in an oven or by using an open-vessel microwave system. After digestion, a stabilizer is added and the solution is taken to volume, then filtered and analyzed either directly or after dilution. The amount of iodine is determined with inductively coupled plasma–mass spectrometry (ICP-MS). The method was validated by experiments to determine its precision, accuracy, linearity, specificity, ruggedness, and robustness. The LOQ of this method is 25–50 μg/kg. The method demonstrated an average RSD of 2.27% during analysis of milk powder and 4.30% during analysis of a dietary supplement tablet reference material. The accuracy of the method as determined with these same reference materials was 100 and 94.2%, respectively. The method has been used successfully on commodity foods, processed foods, dairy products, pet food, infant formula, animal feed, mineral premixes, and a variety of dietary supplements.