SIMULTANEOUS DETERMINATION OF FAT SOLUBLE VITAMINS A, D_3, E AND K_1 IN FORTIFIED MILK POWDERS BY HPLC

摘要

A high performance liquid chromatographic method for the simultaneous determination of four fat soluble vitamins: retinol （vitamin A）, cholecalciferol（vitamin D）, tocopherol（vitamin E） and phylloquinone（vitamin K₁） in fortified milk powders and egg yolk has been developed. The method requires enzymatic hydrolysis of lipid component of the sample as a pretreatment. Several factors which influence the enzymatic hydrolysis were studied-Separation was achieved using μ-Bondapak C-18 column（3.9×300mm）, 98% methanol as mobile phase, a double channel detection was selected; vitamins D₃ E₁ K₁ were detected by UV spectrophotometry （265 nm） first, then vitamin A by fluorometry （EX 325nm, EM 480mm）. The retention times of vitamin A₁ D₃, E and K₁ 4.87, 9.00, 10.58 and 15.45 min respectively. Detection limit were 0.64, 0.25, 0.50 and 0.07 ng; and the recoveries were 90.5%～103.6% 90.0%～95.6%, 91.7%～98.8%, 91.5%～98.6%, respectively. The vitamins A, D₀, E, K₁ contents in foods were determined satisfactorily.