Abstract
During the “Standards Development and International Harmonization: AOAC INTERNATIONAL Mid-Year Meeting,” on June 29, 2011, the method “Determination of Vitamin B12 in Infant Formula and Adult Nutritionals Using HPLC After Purification on an Immunoaffinity Column” was recommended by an Expert Review Panel and adopted as AOAC Official First Action status. The method is applicable for the determination of vitamin B12 in milk-based infant formula. Vitamin B12 is extracted from the sample in sodium acetate buffer in the presence of potassium cyanide. After purification and concentration with an immunoaffinity column (IAC), vitamin B12 is determined by LC with UV detection (361 nm). Data supplied by CLF demonstrated linear response over a wide range of concentrations (1.4–39 μg/100 mL). The analytical range is 0.2–10 μg/100 g, depending on the capacity of the IACs (0.01–0.5 μg), the input weight, and dilutions. Recovery rates were assessed using National Institute of Standards and Technology SRM 1849, and determined to be 95.1%, with SD of 0.34 and CV of 9.0. Measurement uncertainty (UE) was 0.8 μg/100 g, which was calculated from the validation data. It is an expanded measurement uncertainty and was obtained through multiplication with a coverage factor k. LOQ values were reported as 0.10 μg/100 g. The performance characteristics of the method met the standard method performance requirements set forth by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals; thus, the method was determined to be appropriate for First Action status.
A Practical Way to ISO/GUM Measurement Uncertainty for Analytical Assays Including In-House Validation Data