Vitamin C in Infant Formula and Adult/Pediatric Nutritional Formula by Liquid Chromatography with UV Detection: Collaborative Study, Final Action 2012.22.

To determine the repeatability and reproducibility values of the AOAC INTERNATIONAL First Action Method 2012.22, Vitamin C in Infant Formula and Adult/Pediatric Nutritional Formula by Liquid Chromatography with UV Detection, a collaborative study was organized. The study was divided into two parts: method setup and qualification of participants (part 1) and collaborative study participation (part 2). During part 1, each laboratory was asked to analyze two practice samples using the aforementioned method. Laboratories that provided results within a range of expected levels were qualified for part 2, where they analyzed 10 samples in blind duplicates. Two of the samples were suspected of spoilage during the test and new cans of the same type of product were analyzed by a subset of laboratories in part 3. The results were compared with Standard Method Performance Requirement (SMPR®) 2012.012 established for vitamin C. The precision results were within the requirements stated in the SMPR: 1.4-7.3% and 3.2-11.4% respectively, for repeatability and reproducibility. Finally, Horwitz ratio values were all <2 (0.5-1.7). The Expert Review Panel for Stakeholder Panel for Infant Formula and Adult Nutritionals Nutrient Methods determined that the data presented met the SMPR and therefore recommended the method be granted Final Action status.