The determination of vitamin d in margarine by high performance liquid chromatography

Abstract

AbstractMargarine manufactured in South Africa contains vitamin D added at a level of 1–3 international units per gram. Because of the high ratio of lipid to vitamin D, it is difficult to determine the vitamin content for control purposes. A high performance liquid Chro‐matographic method for the determination of vitamin D in mar‐garine is proposed. The unsaponifiable fraction of a margarine sample is chromatographed twice on an adsorption system. The vitamin D fraction collected from this column is finally injected onto a reverse phase system where vitamins D2 and D3 are separated and quantitated with an ultraviolet detector. Vitamin D2 is used as an internal standard for vitamin D3 or vice‐versa, depending on the form of the vitamin added to margarine. The recovery of 100 ng/g vitamin D3 added to a margarine mix was 100.1% (coefficient of variation 13.2% for 12 replicates) as calculated from the ratio of peak areas. The detection limit is 1 ng vitamin D. Results for 3 samples of margarine and one sample of butter are given.