This study explores the amounts of common chemical ultraviolet (UV) filters (i.e., avobenzone, bemotrizinol, ethylhexyl triazone, octocrylene, and octyl methoxycinnamate) in cosmetics and the human stratum corneum. An ultrasound-vortex-assisted dispersive liquid-liquid microextraction (US-VA-DLLME) method with a high-performance liquid chromatography-diode array detector was used to analyze UV filters. A bio-derived solvent (i.e., anisole) was used as the extractant in the US-VA-DLLME procedure, along with methanol as the dispersant, a vortexing time of 4 min, and ultrasonication for 3 min. The mass-transfer rate of the extraction process was enhanced due to vortex-ultrasound combination. Various C18 end-capped columns were used to investigate the separation characteristics of the UV filters, with XBridge BEH or CORTECS selected as the separation column. Calibration curves were constructed in the 0.05-5 μg/mL (all filters except octocrylene) and 0.1-10 μg/mL (octocrylene) ranges, and excellent analytical linearities with coefficients of determination (r2) above 0.998. The developed method was successfully used to analyze sunscreen. Moreover, experiments were designed to simulate the sunscreen-usage habits of consumers, and the cup method was used to extract UV filters from the human stratum corneum. The results suggest that a makeup remover should be employed to remove water-in-oil sunscreens from skin.
Keywords: UV filters; bio-derived solvent; cup method; human stratum corneum; ultrasound–vortex-assisted dispersive liquid–liquid microextraction.