Facile fabrication of polyaniline coated titania nanotube arrays as fiber coatings for solid phase microextraction coupled to high performance liquid chromatography for sensitive determination of UV filters in environmental water samples
A novel polyaniline coated titania composite nanotube (TiO2@PANI CNT) array was fabricated on a titanium wire by direct electrochemical oxidation. The effects of acid media, the concentration of aniline monomers and applied voltages on the electropolymerization of aniline were investigated. Surface morphological and compositional analyses revealed that a thin PANI coating was uniformly immobilized onto the TiO2 nanotube array. This TiO2@PANI CNT coating combined the merits of both PANI and TiO2, and thereby has several advantages over that of individual PANI and TiO2 coatings such as improved extraction efficiency for UV filters, enhanced mechanical stability and prolonged service life. Coupled with a high performance liquid chromatography-ultraviolet detector (HPLC-UV), the applicability of the developed fiber was evaluated through extraction of UV filters. The linear range is 0.25–500 μg L−1 with correlation coefficients of 0.9953 to 0.9998. The recoveries varied from 92.6% to 110% and the relative standard deviations for single fiber repeatability and fiber-to-fiber reproducibility were between 4.3% and 5.7% and between 6.9% and 9.3%, respectively. The limits of detection ranged from 0.04 to 0.06 μg L−1. The developed SPME-HPLC-UV method is suitable for sensitive determination of UV filters in environmental water samples.