Simultaneous determination of tocopherols, retinol, ester derivatives and β-carotene in milk- and soy-juice based beverages by HPLC with diode-array detection

A simple, sensitive and accurate HPLC method has been developed and validated for the simultaneous determination of alpha-tocopherol, gamma-tocopherol, delta-tocopherol, alpha-tocopheryl acetate, retinyl palmitate, retinol and beta-carotene in milk- and soy-juice based beverages. The assay was performed using a Luna RP- C18 column with methanol: THF: water (67:27:6, v/v/v) as mobile phase, at a flow rate of 0.8 mL/min. Diode-array detector was set at 290 nm for tocopherols, 325 nm for retinols and 440 nm for beta-carotene. The method developed and validated is simple and shows good linearity, precision, accuracy and sensitivity and was applied to the analysis of different commercial mixed beverages. The profile of these compounds was different in milk- or soy-juice. Tocopheryl acetate and retinyl palmitate are added in all milk-juice and free gamma- and delta-tocopherols are characteristic of soy-juice samples. beta-carotene is present in both types of mixed beverages. (C) 2014 Elsevier Ltd. All rights reserved.