Rapid determination of para-phenylenediamine by gas chromatography–mass spectrometry with selected ion monitoring in henna-containing cosmetic products

A rapid method for the determination of para-phenylenediamine (PPD) in cosmetic products, such as henna tattoos has been developed and evaluated. This analytical procedure involved extracting a 10 mg test portion of cosmetic product in 10 mL of ethyl acetate, followed by determination by gas chromatography–mass spectrometry in the selected ion monitoring mode (GC/MS-SIM). 1,4-Phenylenediamine-2,3,5,6-d4 was selected as an internal standard that was added at the beginning of the extraction procedure and used to correct for recovery and matrix effects. The linearity ranged from 1.0 to 1275 μg/mL with a coefficient of determination (r2) greater than 0.999. LOQ and LOD were 1.0 and 0.10 μg/mL, respectively. The recovery in a tattoo product containing PPD was 94% and that for a tattoo product containing no PPD reached 105%. Extraction efficiency of 98% was obtained. This method has been successfully applied to henna temporary tattoo and other henna-related cosmetic products for the determination and quantitation of PPD.