The electrochemical determination of vitamin A. Part I. Voltammetric determination of vitamin A in pharmaceutical preparations

Abstract

The voltammetric oxidation of vitamin A at a carbon paste electrode was used to determine the vitamin A content of some pharmaceutical preparations. Chromatography is not required as a clean-up procedure, therefore time is gained and a potential source of errors is eliminated. Vitamin E (tocopherol), which, in large amounts, interferes in the most widely used methods, is rendered electrochemically inactive in the range of potentials that is of interest. This is achieved by acetylating all of the tocopherols that are present in the sample in alcohol from. The oxidation waves of vitamin A are linearly proportional to the concentration range studied. The work described in this paper is concerned with the alcohol and acetate derivatives of vitamin A.