Application of hollow fiber membrane mediated with titanium dioxide nanowire/reduced graphene oxide nanocomposite in preconcentration of clotrimazole and tylosin.

In this paper, TiO2 nanowires and TiO2 nanoparticles have been successfully anchored on graphene oxide (GO) nanosheets by a facile one-step hydrothermal method. The synthesized TiO2 NWs/RGO and TiO2 NPs/RGO nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. After comparatively studying of the as-made nanocomposites, TiO2 NWs/RGO nanocomposite showed the best adsorbing performance and applied as an attractive efficient sorbent reinforced with microporous hollow fiber membrane through the sol-gel technology. In the following, the selected nanocomposite was utilized for simultaneous preconcentration and determination of clotrimazole and tylosin using high performance liquid chromatography (HPLC)-UV detection, respectively. In order to optimize the extraction conditions through affecting parameters (pH, stirring rate, salt addition, extraction time and volume of donor phase), response surface methodology (RSM) was employed as a powerful statistical technique. Under the optimal conditions, the limit of detection (S/N=3) of proposed HFSPME method, was 0.67 μg L(-1) for clotrimazole and 0.91 μg L(-1) for tylosin with good linear ranges of 1.7-8000.0 μg L(-1) and 4.0-6000.0 μg L(-1). The inter-day and intra-day relative standard deviations (RSD%) at 100 μg L(-1) concentration level were in the ranges of 2.10-3.58% for clotrimazole and 3.45-7.80% for tylosin (n=5), respectively. The proposed microextraction device was extended for determination of ultra trace amounts of target analytes in milk and urine samples with satisfactory results.