APPLICATION OF GEL-PERMEATION CHROMATOGRAPHY AND NON-AQUEOUS REVERSE PHASE CHROMATOGRAPHY TO HIGH-PRESSURE LIQUID-CHROMATOGRAPHIC DETERMINATION OF RETINYL PALMITATE AND BETA-CAROTENE IN OIL AND MARGARINE

Abstract

A high pressure liquid chromatographic method was developed using high pressure gel permeation chromatography (HP-GPC) and high pressure reverse phase chromatography (RP-HPLC) for quantitation of retinyl palmitate and .beta.-carotene. HP-GPC was used for fractionation of vitamin A active compounds from oil preliminary to quantitation on nonaqueous RP-HPLC. HP-GPC fractionation was completed on oil and margarin dissolved in methylene chloride by 2 elution passes through 2 .mu.Styragel (100.ANG.) columns connected in series with methylene chloride as the mobile phase. RP-HPLC separation of retinyl palmitate and .beta.-carotene was achieved on .mu.Bondapak C18 (10 .mu.m), using methylene chloride-acetonitrile (30 + 70). Based on 10 repetitive analyses, recoveries of added .beta.-carotene and retinyl palmitate from vegetable oils were 98.6 .+-. 2.9 and 95.2 .+-. 2.6%, respectively. The coefficients of variation were 2.9% for .beta.-carotene and 2.7% for retinyl palmitate. The determination of vitamin A activity in 7 marginine brands revealed that all but 1 of the margarines contained at least 94% of their label claims. Vitamin A activity in the margarines ranged from 90.6-110.8% of the label declaration.