Measurement of iodide and caffeine content in cellulite reductioncosmetic products sold in the European market

Abstract

Two simple liquid chromatography (LC) separation methods coupled with ultraviolet diode array (UV-DAD) and an electrospray ionisation mass spectrometry (ESI-MS) detection have been developed for the determination of caffeine and iodide content in cellulite reduction cosmetic products. The presence of these substances in cosmetics available in the market should be taken into account in order not to exceed the limits allowed when co-administered with drugs, dietary supplements in order to avoid eventual acute or chronic intoxications. The compounds were separated by reversed phase chromatography with water (0.02% trifluoroacetic acid) and acetonitrile gradient elution and detected by UV-DAD at 254 nm and by ESI-MS ionization mode positive for caffeine and negative for iodide. Paracetamol was used as internal standard. Linearity was studied with UV-DAD in the 5 (10 for iodide) to 200 μg g⁻¹ range, and with ESI-MS in the 0.1 (0.2 for iodide) to 2 μg g⁻¹ range. Good determination coefficients (r² = 0.99) were found in both UV-DAD and ESI-MS detection. At three concentrations spanning the linear dynamic ranges of both UV-DAD and ESI-MS assays, mean recoveries were always higher than 90% for the different analytes and intra-assay and inter-assay precisions were always better than 15%. This method was successfully applied to the analysis of substances under investigation in cellulite reduction cosmetic products freely sold in European herbalist shops, perfumeries and supermarkets.