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Determination of total iodine in infant formula and nutritional products by inductively coupled plasma/mass spectrometry: single-laboratory validation.

Abstract

A single-laboratory validation by inductively coupled plasma-mass spectrometry was developed for the determination total iodine (m/z 127) in infant formula and adult nutritional products. All samples were digested in nitric acid using a closed vessel microwave oven system; Te (m/z 130) was used as an internal standard. To prevent loss of iodine, ammonium hydroxide solution was added to the samples immediately after digestion. The method quantitation limit for total iodine was 0.3 ng/mL, but a practical LOQ was used at 1.0 ng/mL, a concentration at which there was a negligible bias due to nonlinearity. The total iodine concentrations (112-1900 ng/g) in 14 out of 15 nutritional products were within specification limits. Within-day and day-to-day (6 independent days) precision values were < 10% RSD. The observed precision for the overall mean (18 independent days) of a control sample was approximately 4% RSD. In two National Institute of Standards and Technology standard reference materials, total iodine results were within certified limits. Sample spike recoveries for all 15 nutritional products were 92-105%. The data show that a conventional microwave oven digestion procedure can be used to prepare samples for iodine determination. Therefore, this technique is very compatible with other methods being proposed as modern official methods for the analysis of minerals in nutritional products.

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  • Publisher Full Text
  • Authors

    Pacquette LH, Levenson AM, Thompson JJ

    Source

    Journal of AOAC International 95:1 pg 169-76

    MeSH

    Dietary Carbohydrates
    Dietary Fats
    Dietary Proteins
    Food, Formulated
    Humans
    Indicators and Reagents
    Infant
    Infant Food
    Iodine
    Limit of Detection
    Mass Spectrometry
    Microwaves
    Nitric Acid
    Powders
    Quality Control
    Reference Standards
    Reproducibility of Results
    Software
    Solutions

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    22468356