EXPERIMENTS TO DETERMINE THE COMPOSITION OF ALDEHYDE FUCHSIN SOLUTIONS.

Abstract

SYNOPSIS The electrophoretic analysis of aldehyde fuchsin solutions in 70 p.c. ethanol between pH 2·5 and 3·5 shows that the dye is basic, and that solutions of different ages have different components. Young solutions possess reddish violet and red components, the latter probably representing unused basic fuchsin which soon disappears. The oldest solutions possess bluish violet, reddish violet, and bluish green components, of which the latter is the most mobile. It is suggested that the colours of the components may represent the state of substitution of their constituent molecules, and that the mobilities of the components may be the result of polymerization. An experiment with precipitated dye showed that the bluish violet component of old dye was more soluble in acidified 70 p.c. ethanol than the reddish violet component of young dye. The bluish violet component at saturation was as good a stain as young reddish violet dye, whereas the old dye from which the bluish violet component was precipitated was a slow and weak dye. It is suggested that the ageing of aldehyde fuchsin may involve a change of solubility as a result of increase of molecular weight, and this may contribute to the poor staining of old solutions.