Rapid high-performance liquid chromatographic method for the simultaneous determination of retinol, α-tocopherol and β-carotene in human plasma and low-density lipoproteins

A reversed-phase HPLC method with diode-array detection was used to simultaneously determine retinol, alpha -tocopherol and beta -carotene in human plasma and low-density lipoproteins. An aliquot of sample was de-proteinized with ethanol containing alpha -tocopherol acetate as internal standard, and the analytes were extracted twice with hexane. The solvent was evaporated to dryness under a stream of nitrogen and the residue was redissolved in methanol to be injected directly into the HPLC system. A multiple solvent system based on methanol. butanol and water at a flow-rate of 2 ml/min and held at 45 degreesC provided clear separation of these compounds in only 8 min. The method showed good linearity, precision and accuracy for all compounds. Owing to its simplicity, this method may be useful in routine clinical and epidemiological work. (C) 2001 Elsevier Science B.V. All rights reserved.