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

CODE:

DATE:

PAGE:

VER:

Purpose:

AOAC 2012.10

Jan 2014

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04

AOAC MLT Study

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DL-α-tocopherol (mg/mL) = ABS × 100 × 10 75.8 3

Where: ABS = average absorbance reading, determined above; 75.8 = extinction coefficient of tocopherol at 292 nm; 10 = conversion of percentage to mg/mL.

Calculation of working standard concentrations

The concentration of each vitamin in the working standards is calculated from the stock concentration using the appropriate dilution factor as show below.

Vitamin A Palmitate (µg/mL)

=

Stock (µg/mL)

× 4

×

4

×

X

50

50

50

Vitamin A Acetate (µg/mL)

=

Stock (µg/mL)

×

4

×

4

×

X

50

50

50

X

Vitamin E Acetate (mg/mL)

=

Stock (mg/mL)

× 7 × 4 ×

50

50

50

X

Vitamin E Alcohol (mg/mL)

=

Stock (mg/mL)

× 20 ×

4

×

50

50

50

Where as X = 0.5mL, 2mL, 4mL, 8mL, 16mL and 32mL respectively for the calibration levels

L. SAMPLE PREPARATION

a. Transfer 25g (W1), accurately weighed to a 250mL schott bottle. Dissolve using warm water (about 40 to 45 0 C), cool, and make up to 200g (W2) with water. Transfer 5.0g (W3) of reconstituted sample to a screw-top centrifuge tube.

Samples weight (powder equivalent) g = (W1 x W3) / W2

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