Monitoring of Natural Pigments in Henna and Jagua Tattoos for Fake Detection

Temporary tattoos are a popular alternative to permanent ones. Some of them use natural pigments such as lawsone in the famous henna tattoos. Recently, jagua tattoos, whose main ingredients are genipin and geniposide, have emerged as an interesting option. This study was conducted to identify the presence and concentration of henna and jagua active ingredients (lawsone; genipin and geniposide, respectively) in commercial tattoo samples. Since natural pigments are often mixed with additives such as p-phenylenediamine (PPD) in the case of henna, PPD has been included in the study. Green and simple extraction methods based on vortex or ultrasound-assisted techniques have been tested. To determine the compounds of interest liquid chromatography (LC) with diode-array detection (DAD) has been applied; and PPD absence was confirmed by LC-QTOF (quadrupole-time of flight tandem mass spectrometry). This work demonstrated that only one out of 14 henna samples analyzed contained lawsone. For jaguas, genipin was found in all samples, while geniposide only in two. Therefore, quality control analysis on these semi-permanent tattoos is considered necessary to detect these ingredients in commercial mixtures, as well as to uncover possible fraud in products sold as natural hennaThis research was supported by project EQC2018-005011-P (Ministry of Science, Innovation and Universities, Spain. The authors belong to the CRETUS Strategic Partnership (ED431E2018/01). All these programmes are co-funded by FEDER (UE). L.R. acknowledges Xunta de Galicia for her predoctoral contractS