A selective quantitative assay of p-phenylenediamine in henna and hair dyes

P-phenylenediamine (PPD) is an aniline derivative with crystalline appearance easily oxidized to provide a darkness color, therefore used as a color developer or as permanent color in hair dye. PPD has been determined in henna and hair dyes of black, brown, grey, and blonde color of different origins. The aim of this study is to know the concentrations of this substance in hair dyes and compare them with each other. the principle of oxidative-coupling criteria has been followed by the oxidation a PPD in aqueous medium then coupling with 2,7-DHN in basic medium to form a stable complex measured at 582nm. Beer’s law was obeyed from 1.02 to38 µg/mL, The method has high sensitivity and low limits of detection and quantitation (0.36771x104 L.mol-1.cm-1, 0.052 µg/mL and 0.176 µg/mL respectively). Henna contains 0.625 mg PPD /0.2 g which consider the highest value, while hair dyes contain from 0.0525 to 0.3075 mg PPD /0.2 g with an average recovery 99% and average standard deviations of 1.198%