Selective solid-phase microextraction of ultraviolet filters in environmental water with oriented ZnO nanosheets coated nickel-titanium alloy fibers followed by high performance liquid chromatography with UV detection.

Uniform and dense ZnO nanosheets (ZnONSs) as a solid-phase microextraction (SPME) fiber coating were fabricated on the surface of nickel and titanium oxide composite nanosheets (NiO/TiO2CNSs) which were in situ grown on the Nitinol (NiTi) wire in a hydrothermal procedure. The SEM micrographs illustrate that ZnONSs with the average thickness of 50 nm have been electrochemically grown on the NiTi fibers. The interconnected ZnONSs coating presents a porous nanostructure with large surface area. The as-fabricated fiber exhibits high extraction capability and excellent extraction selectivity for ultraviolet (UV) filters among the selected aromatic compounds. The main parameters affecting extraction performance were examined and optimized. Under the optimized conditions, the calibration curves were linear from 0.05 to 500 ng mL-1 with correlation coefficients above 0.999. The limits of detection (S/N = 3) ranged from 0.011 to 0.042 ng mL-1, while the limits of quanitification (S/N = 10) were in the range of 0.037-0.14 ng mL-1. Relative standard deviations (RSDs) for the single fiber repeatability were less than 7.4% (n = 5) and RSDs for the fiber-to-fiber reproducibility were below 8.2% (n = 5). The proposed method was successfully applied to the proconcentraction and determination of trace UV filters in real water samples. Moreover, the ZnONSs coating can be fabricated in highly reproducible manner with long durability.