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

- Simultaneous determination of tocopherols, retinol, ester derivatives and β-carotene by HPLC.
- The method developed and validated shows good linearity, precision, accuracy and sensitivity.
- HPLC method was applied to the analysis of milk- and soy-juice based beverages.

A simple, sensitive and accurate HPLC method has been developed and validated for the simultaneous determination of α-tocopherol, γ-tocopherol, δ-tocopherol, α-tocopheryl acetate, retinyl palmitate, retinol and β-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 β-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 γ- and δ-tocopherols are characteristic of soy-juice samples. β-carotene is present in both types of mixed beverages.