Preparation and characterization of Au-ZrO2-SiO2 nanocomposite spheres and their application in enrichment and detection of organophosphorus agents

Au-ZrO2-SiO2 nanocomposite spheres were synthesized and used as selective sorbents for the solid-phase extraction (SPE) of organophosphorous agents. A non-enzymatic electrochemical sensor based on a Au-ZrO2-SiO2 modified electrode was developed for the selective detection of organophosphorous pesticides (OPs). The Au-ZrO2-SiO2 nanocomposite spheres were synthesized by the hydrolysis and condensation of zirconium n-butoxide (TBOZ) on the surface of SiO2 spheres and then the introduction of gold nanoparticles on the surface. Transmission electron microscopy and X-ray photoelectron spectroscopy were performed to characterize the formation of the nanocomposite spheres. Fast extraction of OP was achieved by the Au-ZrO2-SiO2 modified electrode within 5 min via the specific affinity between zirconia and the phosphoric group. The assay yields a broad concentration range of paraoxon-ethyl from 1.0 to 500 ng mL(-1) with a detection limit of 0.5 ng mL(-1). This selective and sensitive method holds great promise for the enrichment and detection of OPs.