Analyzing Tattoo Pigments in a Laboratory Setting: Application of UV-Vis and FTIR Spectroscopy Methods supported with Chemometric Modelling

Abstract

Abstract Physicochemical characterization of tattoo inks has a major impact on their safe usage in tattoo art. Analytical measurements of pigments used in tattoo inks is a real challenge when monitoring their quality. UV-Vis (ultraviolet visible) and Fourier-transform infrared (FTIR) spectroscopy with chemometrics could be used to predict pigment contents in tattoo inks. This study sought to determine the pigments red (PR) 170/254 and pigment blue (PB) 15:3 content, purchased from different suppliers, to examine the different chemical structures and existing impurities of the samples. In this study, UV-Vis and FTIR spectra were collected, and regression models were used to analyze the data. There were significant correlations across both spectrum areas, with coefficients of determination for cross validation greater than 0.7 for most parameters. The two spectroscopic methods come to almost identical results with regard to pigment identity. UV-Vis spectroscopy was found to be suitable method for analyzing changes in pigment concentration and structural evolution. Chemometric modeling showed improved predictions of FTIR parameters, especially in the functional group and fingerprint region of the spectra. The results highlight the significance of utilizing UV-Vis/IR wavelengths to determine pigment structures in samples from various suppliers.