Glycerol Dichlorhydrin and Vitamin A

Abstract

THE use of ‘activated' glycerol dichlorhydrin as a reagent for the colorimetric or absorptiometric estimation of vitamin A has been proposed by Sobel and Werbin¹. As reported, the reaction appears attractive in view of the stability of the chromophor, which makes for ease of measurement. A disadvantage is the low activity of the reagent compared with chloroformie antimony trichloride (Carr–Price reaction) ; the E (1 per cent, 1 cm.) 550 mµ value per unit of vitamin A is only about 25 per cent of the corresponding E(1 per cent, 1 cm.) 620 mµ (Carr–Price) value. The pure compound does not react at all; ‘activation' is effected by distillation with 1–2 per cent antimony trichloride¹; but no account of what causes ‘activation' has yet appeared.