Electrophoretic deposition strategy for the fabrication of highly stable functionalized silica nanoparticle coatings onto nickel-titanium alloy wires for selective solid-phase microextraction.

A new strategy for the immobilization of phenyl-functionalized silica nanoparticles onto nickel-titanium alloy wires is presented. The homogeneous and compact silica nanoparticle coating was achieved on the hydrothermally treated nickel-titanium wires with large surface area by electrophoretic deposition, and followed by self-assembled modification of phenyltrichlorosilane. Coupled to high-performance liquid chromatography with ultraviolet detection, the extraction performance of the fabricated fiber was evaluated using typical aromatic compounds in direct-immersion mode of solid-phase microextraction. Due to its high extraction efficiency and good selectivity for ultraviolet filters, the novel fiber was employed to investigate the key factors affecting the extraction of ultraviolet filters. Under the optimized conditions, the proposed method presented linear ranges from 0.05 to 300 μg/L with correlation coefficients higher than 0.999 and limits of detection from 0.005 to 0.058 μg/L. Relative standard deviations were below 4.3 and 5.6% for intraday and interday analyses at the spiking level of 50 μg/L ultraviolet filters with the single fiber, respectively. The proposed method was successfully applied to the selective concentration and sensitive detection of target ultraviolet filters from environmental water samples. Furthermore, the developed fiber can be used at least 200 times, and fabricated in a precisely controllable manner.