| One of the QA tools used to evaluate manufactured hair color finished products with respect to a reference or a previously approved lot is a hair dye-out. The results/interpretations of the dye-out are somewhat subjective. In addition, quality evaluations on the raw material dyes used in the hair color finished products are limited to sophisticated, instrumental techniques such as High Performance Liquid Chromatography (HPLC).;Spectrodensitometry is an analytical technique designed to provide objective quantitative and qualitative information of Thin Layer Chromatography (TLC) results. The technique measures, in situ, components separated on a TLC plate through the use of visible, UV, or fluorescent light.;This paper discusses: (1) the evaluation of technique parameters associated with Spectrodensitometry, (2) the results of quantitative methods for dye raw materials and hair color finished products, and (3) the results of TLC quantitation and interpretation versus visual hair dye-out differences and chemist interpretations. |
