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

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. (2) Note: The use of different internal standard solution preparations for the standards and samples is acceptable as long as the actual respective weights or concentrations are applied to standards and samples and the two solutions are prepared using the same lot of 5-methyl-tryptophan. c) Tryptophan Concentration in Samples

= (CTS – CTB) x (volume / SW) Volume

TRP g

x ( 100g /

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