Understanding the chemical and mineralogical composition of commercial henna and jagua tattoos and dyes—a multi-analytical approach

Temporary tattoos and dyes constitute a great analytical challenge in relation to the regulatory control of their ingredients. Most of these commercial products are not labeled according to their content and their chemical nature is highly diverse. Therefore, it is necessary to analyze these complex samples to evaluate the potential presence of metallic impurities, to ensure the safety of cosmetic products contributing to health protection. This study proposes a multi-analytical methodology, which includes handheld X-ray fluorescence (h-XRF) and X‐ray diffraction (XRD), complemented by variable pressure scanning electron microscopy coupled with energy-dispersive X‐ray spectrometry (VP-SEM–EDS) to fully characterize 34 commercial samples of jagua and henna tattoos and dyes. The approach allowed the identification of the main constituents providing complementary compositional data and differences between sample types were established. In addition, information on the degree of natural pigments homogeneity was also obtained. The results’ discussion considering the current European cosmetics regulation may be useful to support the drafting of safety requirements and specific regulation. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00216-022-04194-1.