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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DATE:
PAGE:
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Purpose:
AOAC 2012.10
Jan 2014
1 of 11
04
AOAC MLT Study
Page: 5 of 11
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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