Rapid electrochemical preparation of porous sponge-like zinc–zinc oxide coating deposited on an etched stainless steel fiber for selective determination of UV filters in environmental water samples

Abstract

A novel porous sponge-like zinc–zinc oxide (Zn–ZnO) coating was directly prepared on an etched stainless steel wire substrate as a solid-phase microextraction (SPME) fiber via previous electrodeposition of a robust ZnO coating. The scanning electron micrograph of the Zn–ZnO coated fiber exhibits a porous spongy nanostructure with a large surface area. The SPME performance of the prepared fiber was investigated for the concentration and determination of polycyclic aromatic hydrocarbons, phthalates and ultraviolet (UV) filters by high performance liquid chromatography coupled with UV detection (HPLC-UV). It was found that the porous sponge-like Zn–ZnO coating exhibited high extraction capability, good selectivity and rapid mass transfer for some UV filters. The main parameters affecting extraction performance were investigated and optimized. Under optimized conditions, the calibration graphs were linear over the range of 0.1–200 μg L⁻¹. The limits of detection of the proposed method were 0.032–0.064 μg L⁻¹ (S/N = 3). The single fiber repeatability varied from 5.5% to 7.2% and the fiber-to-fiber reproducibility ranged from 7.1% to 8.3% for the extraction of spiked water with 50 μg L⁻¹ UV filters (n = 5). The established SPME-HPLC-UV method was successfully applied to the selective concentration and sensitive determination of target UV filters from real environmental water samples with recoveries from 80.3% to 99.2% at the spiking level of 5 μg L⁻¹ and 50 μg L⁻¹. The relative standard deviations were below 9.3%.