Application of gel permeation chromatography and nonaqueous reverse phase chromatography to high pressure liquid chromatographic determination of retinyl palmitate in fortified breakfast cereals
Landen, W.O.
Journal - Association of Official Analytical Chemists 63(1): 131-136
1980
ISSN/ISBN: 0004-5756 PMID: 7380783 Document Number: 155585
A high pressure liquid chromatographic (HPLC) method was developed by determining retinyl palmitate in cereals. Retinyl palmitate is fractionated from other methylene chloride-soluble components by using high pressure gel permeation chromatography (HP-GPC) followed by quantitation with nonaqueous reverse phase HPLC (RP-HPLC). HP-GPC fractionation was accomplished using 2 .mu.Styragel (100 .ANG.) columns connected in series on sample extracts in methylene chloride with methylene chloride as the mobile phase. A valve designed to facilitate the collection of the vitamin A fraction was installed in-line between the refractive index and absorbance detectors. RP-HPLC quantitation was achieved on .mu.Bondapak C18 (10 .mu.m) using methylene chloride-acetonitrile (30 + 70). Based on 23 repetitive analyses, recovery of vitamin A as retinyl palmitate in cereal products was 95.4 .+-. 4.2% with spiking levels of 21.4-140 .mu.g/g. Vitamin A in 15 cereals, representing brain, corn, oats, rice and wheat, ranged from 34 to 194% of the declared level. The HPLC procedure was compared with the AOAC [Association of Official Analytical Chemists] offical colorimetric method and with an UV spectrophotometric method.