Determination of Paraphenylenediamine in Hair Dyes Formulation Using Visible Spectroscopy

Paraphenylenediamine (PPD), which stands for para-phenylenediamine, is a substance commonly present in hair dyes and is a potent sensitizer and reported to have adverse effects, including skin rashes, allergies, etc. This research study introduces a newly developed and rigorously tested visible spectrophotometric technique for accurately measuring the quantity of PPD in hair dye products. The proposed method relies on a colorimetric reaction between PPD and Folin–Ciocalteu phenol (FC) reagent in the presence of sodium hydroxide (NaOH), which results in a PPD-Folin’s reagent complex that is blue in color. To create a standard calibration curve, various concentrations of PPD solutions within the range of 2 to 10 μg/mL, dissolved in 0.1N NaOH, were combined with 1.5 mL of FC reagent solution and scanned at 645 nm. The method was then used to estimate the amount of PPD in three marketed hair dye formulations. The technique demonstrated accuracy and precision, with a detection limit of 0.2445 μg/mL and a quantification limit of 0.7411 μg/mL. The level of PPD observed in three marketed formulations was between 10 to 12.5 μg/mL. During the study, it was observed that the black henna pack contained high concentrations of PPD