Application of TLC and HPTLC in the analysis of semipermanent hair dyes

Semipermanent or direct colouring includes any product capable of affecting to some extent a change in the natural hair colour that will last through at least five shampoo washings. Semipermanent dyes are simple and easy to use, as opposed to oxidation dyes, and are normally formulated for application on nonbleached hair. Following increases in supply of such formulations, we have started an analysis for quality control purposes of 21 commonly marketed dyestuffs (nitroaminobenzenes, anthraquinone and Arianor dyes) and 20 colouring products manufactured by four leading companies. By using TLC (silica gel and reversed phase) and HPTLC (silica gel) procedures we have determined relative retention values to 1,3-diamino-4-nitrobenzene of standards and dyes found in the commercial products. All the values reported (standards and samples) are the average of five analytical results (+/-SD).