At the "Standards Development and International Harmonization: AOAC INTERNATIONAL Mid-Year Meeting," on June 29, 2011, an Expert Review Panel agreed that the method "Determination of Vitamin B-12 in Infant Formulas and Adult Nutritionals by Liquid Chromatography/UV Detection with Immunoaffinity Extraction" be adopted AOAC Official First Action status. The method is applicable for the determination of vitamin B-12, which includes added cyanocobalamin and natural forms, making it applicable to both fortified and nonfortified products. Vitamin B-12 is extracted from the sample in sodium acetate buffer in the presence of sodium cyanide (100 degrees C, 30 min). After purification and concentration with an immunoaffinity column, vitamin B-12 is determined by LC with UV detection (361 nm). A single-laboratory validation study was conducted on a range of products, including milk- and soy-based infant formulas, cereals, cocoa beverages, health care products, and polyvitamin premixes. The method demonstrated linear response over a large range of concentrations, recovery rates of 100.8 +/- 7.5% (average +/- SD), repeatability RSD (RSDr) of 2.1%, and intermediate reproducibility (RSDIR) of 4.3%. LOD and LOQ values were 0.10 and 0.30 mu g/100 g, respectively, and correlation with the reference microbiological assay was good (R-2 = 0.9442). The results of the study were published in J. AOAC Int. 91, 786-793 (2008). The performance characteristics of the method met the standard method performance requirements set forth by the Stakeholder Panel on Infant Formula and Adult Nutritionals; thus, the method was determined to be appropriate for First Action status.
