Determination of a hair dye using different derivatization agents and HPLC in combination with UV, electrochemical, and fluorescence detection

Comparative studies using UV, fluorescence, and electrochemical detection after HPLC separation were performed to determine the hair dye N,N-bis(hydroxyethyl)-p-phenplenediamine PPDA. For the analysis of this substance in the extraction fluid with regard to skin permeation, sensitivity and selectivity were the most important parameters. Reaction with 2-(4-isocyanatophenyl)-6-methyl-benzothiazole MBP and subsequent coulometric detection in the oxidative mode proved to be superior to fluorescence and UV detection. As future hair dyes may also possess amino and/or hydroxyl groups the method developed may be transferable.