AOAC OMA# 2017.03 (Final Action)-OMB

2017.03 (JULY 2018) Amino-02 Tryptophan by enz hyd_Abbott Labs_Method

FOR ERP USE ONLY DO NOT DISTRIBUTE

HPLC Determination of Total Tryptophan in Infant Formula and Adult/Pediatric Nutritional Formula Following Enzymatic Hydrolysis

Jonathan Draher and Norman White Abbott Nutrition, Division of Abbott Laboratories

is injected onto a C-8 column with reference standards and enzyme blank preparations and the analytes of interest detected and quantified fluorometrically.

B . Sample Size and Applicability Method is applicable to infant formula and pediatric/adult nutritional products in both powder and liquid forms. Powder samples can be analyzed directly or after reconstitution to ready to fee concentrations. Below are some recommended sample weights and examples: Typical Sample Weights: Target 30 – 50 mg of protein into the sample preparation RTF: 2.0g PWD: ~0.3g but not exceeding 50 mg protein or 2.7g of 25/225 reconstitution with water [0.3g x 225/25 = 2.7g] SRM 1849a : Protein = 13.72 g/100g, or 137.2 mg/g; 0.3g x 137.2 mg/g = 41.16 mg protein into prep. @ 10/100 reconstitution: 2.7 SW : 137.2mg/g x 10/100 x 2.7g = 37.04mg protein If weighing powder direct, add 2 mL water to dissolve the powder.

C. APPARATUS 1. Equipment

a) Analytical balance b) Micro-Analytical Balance

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