The determination of vitamin D in the presence of vitamin A

Abstract

A method has been developed for eliminating vitamin A interference in the determination of vitamin D. The procedure depends upon the oxidation of vitamin A alcohol by means of manganese dioxide to vitamin A aldehyde which reacts with p-aminobenzoic acid to form a derivative that is readily extracted from organic solvents with aqueous sodium hydroxide solution. Vitamin D remains in the organic solvent. Final traces of impurities that interfere in the vitamin D determination are removed by chromatography on floridin earth and on alumina. Vitamin D is determined by the antimony trichloride colour reaction.