Tocopherols in human milk: analytical method using high-performance liquid chromatography.

A procedure for the determination of tocopherols in human milk using normal phase high-performance liquid chromatography (HPLC) is described. The method involves extraction of the total lipid from milk and direct injection of the dissolved lipid into the HPLC without further fractionation. Operating conditions are as follows: instrument, Varian Model 5000 Liquid Chromatograph; column, Alltech-NH2 (25 cm X 4.6 mm); solvents, n-hexane:2-propanol (98:2); flow rate, 2.0 ml/min; detector, 290 nm; and absorbance range, 0.01. Chromatographic separation of the tocopherol isomers, alpha, beta, gamma, and delta, was achieved. The tocopherol isomers of milk were separated, allowing quantitation of alpha- and gamma-tocopherol, the predominant milk isomers. Good recovery, reproducibility, and precision for the method were demonstrated.