Determination of mercaptoacetic acid in hair waving and depilatory products

Abstract

Identification of mercaptoacetic acid in hair waving and depilatory products containing other mercapto acids is possible by using thin-layer chromatography.

However, gas-chromatographic methods are to be preferred for accurate quantitative determination. Four gas-chromatographic methods are proposed; the first and the second involve derivatisation of the mercaptoacetic acid with diazomethane to the methyl ester, methyl thioether derivative. In the third method, the mercaptoacetic acid is converted into its methyl ester by use of p-toluenesulphonic acid. The last method involves the direct chromatography of underivatised mercaptoacetic acid.