OMB Meeting Book_9-11-14

Vitamin A & E - MLT For ERP Use Only DO NOT DISTRIBUTE

SIMULTANEOUS DETERMINATION OF 13-CIS AND ALL-TRANS VITAMIN A PALMITATE (RETINYL PALMITATE), VITAMIN A ACETATE (RETINYL ACETATE), AND TOTAL VITAMIN E (Α-TOCOPHEROL AND DL-Α-TOCOPHEROL ACETATE) IN INFANT FORMULA AND ADULT NUTRITIONALS BY NORMAL PHASE HPLC

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AOAC 2012.10

Jan 2014

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04

AOAC MLT Study

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c. Repeat the reading a further two times, rinsing the sample cuvette with the solution before each reading. Calculate the average absorbance reading. d. The potency of the vitamin A Acetate stock solution is then calculated as follows:

Vitamin A Acetate (µg/mL) = ABS × 100 × 100 × 10000 1560 3 3

Where: ABS = average absorbance reading, determined above; 1560 = extinction coefficient of retinyl acetate at 325nm; 10000 = conversion of percentage to µg/mL.

dl-α-Tocopherol Acetate

a. Pipette 3mL of stock solution E1 into a 100mL volumetric flask and make up to volume with ethanol . b. Determine the absorption at 284 nm, zeroed against ethanol in a 1cm quartz cell. c. Repeat the reading a further two times, rinsing the sample cuvette with the solution before each reading. Calculate the average absorbance reading.

d. The potency of the dl-α-tocopherol acetate stock solution is then calculated as follows:

DL-α-tocopherol acetate (mg/mL) =

ABS × 100 × 10 43.6 3

Where: ABS = average absorbance reading, determined above; 43.6 = extinction coefficient of tocopheryl acetate at 284 nm; 10 = conversion of percentage to mg/mL.

DL-α-Tocopherol

a. Pipette 3mL of stock solution E2 into a 100mL volumetric flask and make up to volume with ethanol. b. Determine the absorption at 292 nm, zeroed against ethanol in a 1cm quartz cell. c. Repeat the reading a further two times, rinsing the sample cuvette with the solution before each reading. Calculate the average absorbance reading. d. The potency of the DL-α-tocopherol stock solution is then calculated as follows:

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