Alumina-titania (Al₂O₃-TiO₂) hollow fiber sorptive microextraction coupled to inductively coupled plasma mass spectrometry for determination of trace elements in diesel and gasoline samples

An alumina-titania (Al₂O₃-TiO₂) hollow fiber membrane was synthesized using the template method coupled with a sol-gel process. The crystal forms of the mixed oxide hollow fiber was evaluated using X-ray diffraction (XRD). The morphological structure and surface characteristics of the Al₂O₃-TiO₂ hollow fiber were characterized by scanning electron microscopy (SEM) and nitrogen adsorption/desorption BET techniques. The synthesized Al₂O₃-TiO₂ hollow fiber membrane was combined with inductively coupled plasma mass spectrometry for on-line preconcentration and determination of trace amounts of Co, Cr, Mo, Ni, Sb and V in diesel and gasoline samples. The optimization of the experimental parameters affecting the preconcentration and determination of target analytes was performed using a full 2⁴ factorial and central composite designs. Under optimized conditions, limits of detection (LOD) (based on the original sample) and limits of quantification (LOQ) ranged 0.1-0.9 and 0.3-3.0 ng L^-1, respectively. The developed method was applied in the determination of trace elements in real diesel and gasoline samples.