title: Determination of total iodine in foods and dietary supplements using inductively coupled plasma-mass spectrometry.
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 microg/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.
authors.affiliation: Covance Laboratories Inc., 3301 Kinsman Blvd, Madison, WI 53704, USA. darryl.sullivan@covance.com
authors.forename: Darryl
authors.initials: D
authors.lastname: Sullivan
authors.forename: Richard
authors.initials: R
authors.lastname: Zywicki
mesh_terms: D000818:Animals; D002138:Calibration; D002417:Cattle; D019587:Dietary Supplements / Q000032:analysis*; D005504:Food Analysis / Q000379:methods*; D006878:Hydroxides / Q000737:chemistry; D007202:Indicators and Reagents; D007455:Iodine / Q000032:analysis*; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods; D008872:Microwaves; D008892:Milk / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D012015:Reference Standards; D015203:Reproducibility of Results; D012996:Solutions
chemical_list: D006878:Hydroxides; D007202:Indicators and Reagents; D017680:Potassium Compounds; D012996:Solutions; D007455:Iodine; C029943:potassium hydroxide