Hair Colors: Classification, Chemistry and a Review of Chromatographic and Electrophoretic Methods for Analysis

At present, the demand for hair color is rising globally. Because commercial hair colors have been reported to possess adverse effects on human health, their formulation is under strict regulation in each country. In this review, we briefly discuss the advantages and limitations of currently available chromatographic and electrophoretic methods, such as high performance liquid chromatography (HPLC), gas chromatography/gas chromatography with mass spectrometry (GC/GC-MS), and capillary electrophoresis (CE) employed for the analysis of dyestuffs present in commercial hair colors. Furthermore, a brief attempt has been made to classify hair colors according to their type and stability on hair. In addition, the chemistry behind dyeing is also briefly surveyed.