AOACSPIFANMethods-2017Awards

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C ampos G iménez & M artin : J ournal of AOAC I nternational V ol . 100, N o . 1, 2017  139

INFANT FORMULA AND ADULT NUTRITIONALS

Vitamin C in Infant Formula and Adult/Pediatric Nutritional Formula by Liquid Chromatography with UV Detection: Collaborative Study, Final Action 2012.22 E sther C ampos G iménez and F rédéric M artin Nestlé Research Center, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland Collaborators: K. Schimpf; L. Butler Thompson; D. Aoude-Werner; J. Dalmas-Le Grandois; J. Wong; J. Chia; I. Malaviole; M. Mapar; T. Nguyen; M. Hoard; G. Joseph; L. Ma; B. Wu; T. Rogers; J. Austad; B.M. Jensen; I. Pedersen; S. Meng Jensen; Y. Zhang; W. Jobgen; C. Weihong; L. Xiuying; H. Chanyuan; D. Woollard; E. Kneeteman; O. Hernández Hernández; E. Beltrán; G. Weerasekera; J. Frueh; P. González; E. Román; M. Carreño; G. Jaudzems; R. Nijman; T. Noorloos; L.K. Yap; S.H. Chooi; G.J. Lautenschlager; S. Christiansen; D. Piot; M. Barba Le Brun

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. V itamin C ( l -ascorbic acid) plays an important role in oxidative stress reactions and is involved in a number of metabolic functions (1). Because humans are unable to synthetize vitamin C, its supply must be ensured through adequate Received July 21, 2016. Accepted by SG August 17, 2016. The method was approved by the AOAC Official Methods Board as Final Action. See “Standards News,” (2016) Inside Laboratory Management , July/August issue. The AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) invites method users to provide feedback on the Final Action methods. Feedback from method users will help verify that the methods are fit for purpose and are critical to gaining global recognition and acceptance of the methods. Comments can be sent directly to the corresponding author. Corresponding author’s e-mail: esther.campos-gimenez@rdls. nestle.com DOI: 10.5740/jaoacint.16-0232

dietary intake. Daily requirements can vary from 75 mg in adult women to 90 mg in adult men (2), and Codex has established a lower limit of 10 mg/100 kcal and a guidance upper level of 70 mg/100 kcal in infant formula and foods for special medical purposes (3). Several official AOAC INTERNATIONAL Methods exist for the analysis of vitamin C in foods, and in particular, in infant formula, as reviewed elsewhere (4). Fontannaz et al. (5) published a method for the quantification of ascorbic and isoascorbic acid in fortified foods, including infant formula and nutritional products.Amodification of thismethodwas proposed to the Expert Review Panel for Stakeholder Panel for Infant Formula and Adult Nutritionals Nutrient Methods (SPIFAN) and was approved asAOAC FirstAction Method 2012.22 in 2012 (6), with a recommendation to advance to a multilaboratory collaborative study. This paper presents the results of the collaborative study. The study took place using SPIFANmatrixes, which represent most of the products in the scope of the project (infant formula and adult nutritionals made from any combination of milk, soy, rice, whey, hydrolyzed protein, starch, and amino acids, with and without intact protein). All samples were blinded and codified before being sent to participating laboratories. AOAC Official Method 2012.22 Vitamin C in Infant Formula and Adult/Pediatric Nutritional Formula Liquid Chromatography with UV Detection [Applicable to the determination of vitamin C ( l -ascorbic acid) in infant formula and adult/pediatric nutritional formula by LC–UV.] Caution : Refer to Material Safety Data Sheets prior to use of chemicals. Use appropriate personal protective equipment when performing tests. Samples First Action 2012 Final Action 2016

A. Principle

l -Ascorbic acid is extracted from the sample using trichloroacetic acid (TCA) in the presence of tris [2-carboxyethyl] phosphine (TCEP) as a reducing agent. Ascorbic acid is then determined by ultra-HPLC (UHPLC) or HPLC with UV detection at 265 nm. Separation takes place in a C 18 column