Determination of six benzotriazole ultraviolet filters in water and cosmetic samples by graphene sponge-based solid-phase extraction followed by high-performance liquid chromatography

An approach for fabrication of graphene sponge (GS)-based solid-phase extraction (SPE) followed by high-performance liquid chromatography (HPLC) with ultraviolet detection (HPLC-UV) is proposed, which was applied to determine the six benzotriazole UV filters in water and cosmetic samples. Several extraction conditions including type of elution solvent, the volume of elution solvent, and salt effect were optimized. Under the optimum conditions, the GS-SPE-HPLC-UV method shows a low limit of detection (LOD, S/N=3) of 0.02-0.08gL(-1) for standard solution, limits of quantification (LOQ, S/N=10) of 0.07-0.26gL(-1) for standard solution, wide linear ranges from 20.0 to 1000gL(-1) for all compounds for standard solution, correlation coefficients (r) of more than 0.999, except for 2-(2-hydroxy-5-methylphenyl)benzotriazole (UV-P), and acceptable reproducibility (relative standard deviations, RSDs <6.5% for intra-day, RSDs <8.1% for inter-day). The satisfactory recoveries were obtained in the range 89-105% with RSDs lower than 9.8% at the three spiked levels of 20, 50, and 100gL(-1). Every home-made GS-SPE cartridge can be reused for more than 60 cycles. The method is facile, low-cost, rapid, sensitive, and suitable for the determination of UV filters in water and cosmetics samples.