AOAC SPIFAN Nutrients ERP-Final Review (Jan. 2019)

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

d) Accurately weigh 0.0400 ± 0.0020 grams to 50 mL with water. Initially add ~of 5-methyl-DL-tryptophan on a Micro-Analytical balance, record the weight, and transfer to a 50 mL volumetric flask. Add about 25 mL waterof Laboratory Water, and stir witha small stir bar. Due to the slow rate of dissolution, may stir overnight it is most convenient to place the flask in a refrigerator . Store frozen. to stir overnight or until the powder dissolves. Once dissolved, rinse and remove the stir bar and bring to a final volume of 50 mL with water. Storage: Freeze solution in vials. Expiration date : 6 months . e) Tryptophan Stock Standard Solution - (. Weigh 0.0100 ± 0.0010 grams per of tryptophan and transfer to a 100 mL ) Store frozen. volumetric flask. Record weight. Add close to 50 mL of Laboratory Water and dissolve the tryptophan powder by sonicating the solution (about 3 minutes). Let solution cool to room temperature and bring to a final volume (100 mL) using Laboratory Water. Storage: freeze solution in vials. Expiration date : 6 months. Combine the appropriate aliquot of tryptophan and internal standard stock solutions together in separate 50 mL volumetric flasks (one for four working levels.each level) following the table below: Standard TRP Stock Sol. Int. Std. Stock VERY LOWVery Low 0. 202 mL 0.5 mL LOW 1.0 mL 0.5 mL MID 5.0 mL 0.5 mL HIGH 10.0 mL 0.5 0.5 mL Add 12.0 mL of methanol to each of the four flasks containing the standard/internal standard mixtures, and bring to volume with water. Transfer e) h)f) Working Standard Solutions:

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