Development and application of analytical methods to identify and quantify components in tattoo pigments and inks

Abstract

This work studied the presence of rosin components in pigments and inks used for tattooing. Rosin abietane diterpenoids, also known as resin acids, are known to oxidize in the presence of air, light, or heat to produce allergenic compounds. To increase its stability, rosin can be modified, and some of the modified components have also been shown to be allergenic. The manufacturing of some pigments used for tattoo inks sometimes involves the use of rosin or modified rosin. The presence of rosin in tattoo inks has thus far not been studied, and as such there is no method developed for its analysis in those matrices. Adverse reactions to tattoos in the form of allergic responses are most often observed in relation to red-colored tattoos, but the cause of those reactions is not known. Hence, it was of interest to study red pigments used in tattoo inks and red tattoo inks themselves, and non-red pigments and inks as well for comparative purposes, to identify compounds that could explain some of the observed allergic reactions.<br /> <br /> Since reference materials of abietic acid, the main rosin component, and rosin oxidation products are either of inadequate purity or not commercially available, this work focused partly on their preparation. The analysis of rosin abietanes by HPLC is preferable over using GC-MS in order to avoid heating and derivatization, but the isomeric analytes are not well separable from each other by HPLC. Therefore, a new UHPLC method was developed for their analysis. Using that method, three red pigments produced as lakes were initially studied to identify the presence of rosin abietanes and their oxidation products and to determine the extent and level of those components. Other red and non-red pigments reported to be used in tattoos were studied next, and a pressurized-solvent extraction method was developed for their extraction from solid pigments. An extensive analytical survey of tattoo inks from various manufacturers and of various colors was conducted after extracting them by an optimized SLE method. A qualitative UHPLC method was also developed to identify the pigments in the surveyed tattoo inks.