NEW ANALYTICAL ASPECTS OF VITAMIN-D IN FOODS

A comprehensive study of vitamin D in foods was undertaken during 1991 -1994 in Finland to develop high-performance liquid chromatographic (H PLC) methods for analysing cholecalciferol, ergocalciferol and their 2 5-hydroxylated metabolites in fish, egg yolk, meat, milk, edible mushr ooms and fortified foods, and to evaluate which vitamin D compounds sh ould be analysed to estimate the total vitamin D contents in these foo ds. The procedures included saponification, extraction and purificatio n using one or two chromatographic steps prior to quantification by HP LC using internal standard methods. Ergocalciferol was used as an inte rnal standard for cholecalciferol and vice versa, and, as first presen ted in the present study, 25-hydroxyergocalciferol was used as an inte rnal standard for 25-hydroxycholecalciferol and vice versa. The method s developed were well suited to determining the contents of ergocalcif erol, cholecalciferol and their 25-hydroxylated metabolites in food. G ood estimates of the vitamin D content of fish or edible mushrooms are obtained if only cholecalciferol or ergocalciferol, respectively, are determined. On the other hand, in addition to cholecalciferol 25-hydr oxycholecalciferol should also be determined from egg yolk, meat and m ilk. Copyright (C) 1996 Elsevier Science Ltd