[Determination of vitamin A in food using high-pressure liquid chromatography. Results of a collaborative study of the Vitamin Analysis Working Group following The LMBG Paragraph 35].

A standard method using HPLC for the quantitative determination of vitamin A in food is described. The test material is saponified with aqueous ethanolic potassion hydroxide, and the vitamin A alcohol liberated is extracted with n-hexane. After concentration of the extract, the residue is dissolved in methanol and the vitamin A content determined, after HPLC separation on a RP-C-18 column, by means of an UV or fluorescence detector. The analytic method had been developed by the working group "Vitamin Analysis" within the frame-work of section 35 LMBG; reproducebility and agreement in results between laboratories were checked in vitamin A enriched milk powder and gruel in a collaborative study in which 13 laboratories participated. The statistical evaluation of the results of the collaborative study has shown sufficient reliability to recommend the method for inclusion in the Official List acc. to section 35 LMBG. The method is applicable for the determination of natural vitamin A and vitamin A ester added to dietetic food.