Improved reverse phase liquid chromatographic determination of vitamins A and D in fortified milk.
A method for determination of vitamins A, D2, and D3 on the same 6 mL sample of fortified milk is described. A special indicator permits selection from the cleanup column of a fraction that contains all vitamin D and is free of cholesterol interference for final measurement by reverse phase liquid chromatography. Conservation of analyst's time and expensive solvents results from the relatively small sample processed. The average recoveries and standard deviations were, respectively, 94.1% and 4.8 for vitamin D2, 91.1% and 5.2 for vitamin D3, and 92.2% and 2.6 for vitamin A in nonfat skim milk; 86.5% and 9.4 for vitamin D2, and 83.7% and 4.9 for vitamin D3 in homogenized whole milk. Detectable minima are about 100 IU vitamin A/qt and 50 IU vitamin D2 or D3/qt.
D000537:Aluminum Oxide; D000818:Animals; D002417:Cattle; D002762:Cholecalciferol / Q000032:analysis; D002853:Chromatography, Liquid / Q000379:methods; D004872:Ergocalciferols / Q000032:analysis; D008892:Milk / Q000032:analysis*; D014801:Vitamin A / Q000032:analysis*; D014807:Vitamin D / Q000032:analysis*
D004872:Ergocalciferols; D014801:Vitamin A; D014807:Vitamin D; D002762:Cholecalciferol; D000537:Aluminum Oxide