Application of inductively coupled plasma/mass spectrometry for the measurement of chromium, selenium, and molybdenum in infant formula and adult nutritional products: First Action 2011.19.

摘要

An ICP-MS method was developed for the simultaneous determination of Cr, Se and Mo in infant formulas and other nutritional products. All samples were digested using a closed vessel microwave oven system, together with Ni and Te internal standards. The practical quantitation limits for Cr, Se and Mo were 0.4, 0.2 and 0.4 ng/ml, respectively; dilution factors were 250 for powders and 50 for liquids. The Cr, Se and Mo concn. in 10 nutritional products were within specification limits; within-day and day-to-day (6 independent days) precision values were <5% relative s.d. For 2 control samples, the observed precision was <=2% relative s.d. over 10 independent days. Cr, Se and Mo results were within the certified limits in 3 National Institute of Standards and Technology standard reference materials. Average sample spike recoveries for 10 nutritional products ranged from 93 to 107%. Robustness studies showed a minimal effect from concomitant easily ionized element concn. However, the choice of internal standard and matrix-matching carbon content were critical to obtaining accurate Se results. All indications are that this procedure would be a suitable candidate as a global reference method for the determination of these trace elements in infant formulas and adult nutritional products.