AOAC OMA# 2017.03 (Final Action)-OMB

2017.03 (JAN 2019) Amino-02-(ERP Review for Pubs) Tryptophan by enz hyd_Abbott Labs_Method_10172018

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

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:

Conc. of Stock: 100 mg/L (tryptophan) Dilutions: made in 50 mL volumetric flasks. Very Low Standard: Conc. in mg/L = 100 mg/L x 0.2/50mL Conc. Of Very Low std = 0.400 mg/L Low Standard: Conc. in mg/L = 100 mg/L x 1mL/50mL Conc. of Low Standard = 2.00 mg/L Mid Standard: Conc. in mg/L = 100 mg/L x 5mL/50mL Conc. of Mid Standard = 10.00 mg/L High Standard: Conc. in mg/L = 100 mg/L x 10mL/50mL Conc. of High Standard = 20.00 mg/L

b) Internal Standard (where indicated) (1) The 5-Methyl-DL-tryptophan weight from E.3.d) is used in the calculations as the internal standard (IS) amount. Conversion to concentration is unnecessary.

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