Abstract
This HPLC method, with both variable UV and fluorescence detection, allows for the simultaneous determination of vitamin A palmitate, vitamin A acetate, and total vitamin E in infant, pediatric, and adult nutritional formulas. The concentration of each vitamin form is calculated by comparison with standards of known concentration. Following hydrolysis, the vitamins are extracted into iso-octane and analyzed by normal phase (NP) HPLC. The method was evaluated for linearity, precision, and accuracy using a selection of the Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) matrixes, including milk-based, soy-based, and hydrolyzed protein, as well as high- and low-fat products. A single-laboratory validation has been completed for all analytes using a selection of SPIFAN matrixes. Performance parameters included a working range of 2–450 μg/100 g ready-to-feed for vitamin A and 0.03–8.0 mg/100 g reconstituted final product for vitamin E. LOD was <1.0 μg and <0.1 mg/100 g reconstituted final product for vitamins A and E, respectively; RSD was 1.08–8.70% over a range of concentration; and average recoveries of 97.4–101.3%. Repeatability of <4% for vitamin A and <8% for vitamin E was calculated from five laboratories using this method. Results indicate that this method is suitable for the analysis of vitamins A and E in all forms of infant, adult, and pediatric formulas (powders, ready-to-feed liquids, and liquid concentrates). The Expert Review Panel (ERP) of Infant Formula reviewed this method separately for vitamins A and E, including all available method validation data at the AOAC INTERNATIONAL Annual Meeting on September 29, 2012. Following evaluation of the data for both methods, the ERP agreed that both methods met the standard method performance requirements articulated by SPIFAN. The ERP granted First Action status to both methods, and recommended that a single method be published for the simultaneous determination of vitamin A palmitate, vitamin A acetate, and total vitamin E (DL-α-tocopherol and DL-α-tocopherol acetate) in infant formula and adult nutritionals by NP HPLC.
Determination of silicon dioxide coated on aluminium oxide powder by diffuse reflectance infrared Fourier transform spectrometry.