6. AOACSPIFANMethods-2018Awards

6

J audzems : J ournal of AOAC I nternational V ol . 99, N o . 4, 2016  1113

OFFICIAL METHODS

Chloride in Milk, Milk Powder, Whey Powder, Infant Formula, and Adult Nutritionals by Potentiometric Titration Method: First Action 2016.03 G reg J audzems Nestlé USA, Inc., Quality Assurance Center, Chemistry Technical Services, 6625 Eiterman Rd, Dublin, OH 43017 T ian Y an and W an X in Chinese Academy of Inspection and Quarantine Comprehensive Test Center, Beijing 100123, China

S takeholder P anel on I nfant F ormula and A dult N utritionals E xpert R eview P anel for SPIFAN N utrient M ethods

Introduction

The presented method is a combination of AOAC First Action methods 2015.07 (1) and 2015.08 (2). As both methods were reviewed by the Expert Review Panel as equivalent, the authors were asked to combine the methods into one method. This combined method maintains the performance requirements cited in each separate method single-laboratory validation and therefore meets the Standard Method Performance Requirements (3). AOAC Official Method 2016.03 Chloride in Milk, Milk Powder, Whey Powder, Infant

Darryl Sullivan (Chair) , Covance Laboratories John Austad , Covance Laboratories Sneh Bhandari , Silliker Laboratories Esther Campos-Gimenez , Nestlé

Adrienne McMahon , Nestlé Scott Christiansen , Perrigo

Hans Cruijsen , FrieslandCampina Wil van Loon , FrieslandCampina Jon DeVries , General Mills/Medallion Laboratories Brendon Gill , Fonterra Don Gilliland , Abbott Nutrition Karen Schimpf , Abbott Nutrition Min Huang , Frontage Laboratories Estela Kneeteman , National Institute of Industrial Technology Bill Mindak , U.S. Food and Drug Administration Maria Ofitserova , Pickering Laboratory Shay Phillips , Mead Johnson Guenther Raffler , Central Laboratories Friedrichsdorf– Eurofins Kate Rimmer , National Institute of Standards and Technology Melissa Phillips , National Institute of Standards and Technology David Woollard , Hill Laboratory Jinchuan Yang , Waters Corp.

Formula, and Adult Nutritionals Potentiometric Titration Method  First Action 2016

(Applicable to the determination of chloride in milk, milk powder, whey powder, infant formula, and adult nutritionals by potentiometry, with an analytical range of 0.35–1060 mg chloride/100 g reconstituted product or ready-to-feed (RTF) liquids). Caution : Consult Material Safety Data Sheets for all

substances that are required and considered hazardous. Follow all laboratory safety precautions and wear proper personal protective equipment.

A. Principle

Reconstitute powder samples by dissolving 25 g powder sample in 200 g warm water (40°C); RTF products are ready to use as they are. Precipitate proteins by adding precipitation solutions I and II, and then centrifuge. Acidify the supernatant with nitric acid solution. Titrate chloride ions against standardized silver nitrate solution (0.1 M), potentiometrically using a silver electrode to detect the end point. Common laboratory equipment and, in particular, the following: (a) Analytical balance .—Precision to 0.1 mg. (b) Centrifuge .—Tabletop with rotor for 50 mL conical tubes, capable of operating at ≥12000 × g . (c) Centrifuge tubes .—50 mL, conical, polypropylene. (d) Pipets .—1, 10, 20, 50, and 100 mL, Class A glass volumetric or automatic (Eppendorf or equivalent). B. Apparatus

Submitted for publication April 2016. Adopted as a First Action Official Method by the Expert Review Panel on SPIFAN Nutrient Methods. Approved on: March 16, 2016. Corresponding author’s e-mail: greg.jaudzems@us.nestle.com DOI: 10.5740/jaoacint.16-0123