High-performance liquid chromatography of fat-soluble vitamins. Simultaneous quantitative analysis of vitamins D2, D3 and E. Study of percentage recoveries of vitamins from cod liver oil

Vitamins D2, D3 and E were resolved and quantified by applying reversed-phase high-performance liquid chromatography to extracts of cod liver oil. The method, using two reversed-phase C18 columns and a ternary mixture of acetonitrile, methanol and water as the eluent resolved all fat-soluble vitamins well, including the pair D2-D3. The extraction procedure was studied; the recoveries, using two different solvents (hexane and diethyl ether) for extractions were 60.6 +/- 1.0 and 77.1 +/- 1.1, 56.9 +/- 1.2 and 74.8 +/- 0.8, and 14.1 +/- 0.7 and 89.8 +/- 1.4% for vitamins D2, D3 and E, respectively.