Application of a new sample preparation method based on surfactant-assisted dispersive micro solid phase extraction coupled with ultrasonic power for easy and fast simultaneous preconcentration of toluene and xylene biomarkers from human urine samples

A fast and easy surfactant-assisted dispersive micro-solid phase extraction method coupled with ultrasonic power was used for the simultaneous preconcentration and determination of low levels of hippuric and methyl hippuric acid in human urine samples. In the first step, magnetic nanoparticles was coated by titanium oxide nanoparticles (Fe3O4/TiO2 NPs), afterward characterized by the scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. In the next step, anionic surfactants were thus combined with the synthesized magnetic nanoparticles to create a new adsorbent for increasing the simultaneous extraction of hippuric and methyl hippuric acid. After elution of extracted target molecules by the sorbent, the concentration of these molecules were measured by high-performance liquid chromatography (HPLC-UV). Meanwhile, a statistical approach known as Box-Behnken design was applied for optimizing significant parameters. With the optimum parameters anticipated by the experimental design, the limit of quantification (LOQ) acquired was reported to be 3 mu gL(-1), and the calibration curve was linear within the concentrations of 3-1000 mu gL(-1). Finally, the method was effectively implemented for the determination of low levels of hippuric and methyl hippuric acid in human urine samples.