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

A reversed-phase HPLC method with diode-array detection was used to simulta neously determine retinol, alpha -tocopherol and beta -carotene in human pl asma 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 me thanol to be injected directly into the HPLC system. A multiple solvent sys tem based on methanol. butanol and water at a flow-rate of 2 ml/min and hel d at 45 degreesC provided clear separation of these compounds in only 8 min . The method showed good linearity, precision and accuracy for all compound s. Owing to its simplicity, this method may be useful in routine clinical a nd epidemiological work. (C) 2001 Elsevier Science B.V. All rights reserved .