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

5-methyl-tryptophan. Excessive tailing indicates the need for a new column to restore expected performance. c) Residual Error of Linear Regression: The residual error for any one point of the three point linear regression is not to exceed 5%. In the event of excessive error, repeat the analysis with fresh standard solutions

H. CALCULATIONS

1. Manual Calculations a) Calculate concentrations of the tryptophan standards (mg/L) using the following equations:

(1) Tryptophan Stock Standard Solutions:

TRP (mg/L) = Weight TRP (g) x 1000 mg Volume (L) g Example:

Tryptophan Weight = 0.0100 grams. Dilution = 100 mL volumetric flask.

0.0100 g x 1000 mg =100 mg 0.1 L g L Tryptophan Concentration (stock) = 100 mg/L

(2) Diluted Tryptophan Standard Solutions:

TRP (mg/L) = Stock Conc. (mg/L) x Dilution

Where: Dilution = Volume Stock (mL) Final Volume (mL) Example:

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