Quantitative Analysis of Mixtures of Monazo-dyes used for Food by Direct Densitometry of Transparent Type

Abstract

A method for the quantitative analysis of 4 kinds of monazo-dyes used for food is described. The method consists of paper chromatography and analysis of the resultant spot peak areas by direct densitometry.
The paper-chromatogram-spot volumes of each dye through filters with various wave lengths were approximately proportional to the root square of color concentration as was shown in our previous paper (Shokuhin Eiseigaku Zasshi, 13, 120, 1972.).
The application of direct densitometry to the quantification of the components of monazodyes mixtures was made. For two 2 components mixtures (amaranth and new coccine, tartrazine and sunset yellow FCF), the content of each color was determined densitometrically with reproducibility of 95.7-100.7%. For 4 component mixture of all four dyes above, 84.8-112.1%.