| Organophosphate pesticides(OPs) are broad-spectrum insecticides that have been used in many countries. However, there are excessive pesticide residues in agricultural products and they are serious threat to our health, owning to the abuse of toxic pesticide. Therefore, development of a rapid, reliable and inexpensive method for detecting trace levels of organophosphate pesticides in agricultural products is significant. In this work, a novel biomimetic electrochemical sensor(BECS) for rapid detection of organophosphate pesticides was built. The main results are as follows:(1) Fe3O4, graphene, Au@MIL-101, Au@Ag@MIL-101 and Fe3O4/graphene(Fe3O4@G) were prepared. In addition, a novel MIL@MIP was synthesized by coating the MIP shell onto the surface of metal-organic framework MIL-101 by using diethylphosphonoacetic acid(DPA) as the public template, and tetrae-thoxysilane(TEOS) as the cross-linker. The structure and composition of the prepared Fe3O4@G and MIL@MIP were characterized by transmission electron microscopy(TEM), X-ray diffraction(XRD), Fourier transform infrared(FTIR) and Typical Thermogravimetric analysis(TGA).(2) The GCE was modified by Fe3O4@G and MIL@MIP. The conductivity and the selectivity of the BECS were improved. A novel biomimetic electrochemical sensor(BECS) for rapid detection of methamidophos and omethoate was established. The BECS offered excellent current responses for methamidophos and omethoate with wide linear response ranges of 1.0×10–7–1.0×10-12 mol L-1 and 1.0×10-7–1.0×10-13 mol L-1, respectively. Under optimal conditions, the limition of detection(LOD)(S/N?3) of the BECS was calculated to be 2.67×10-13 mol L-1 for methamidophos and 2.05×10-14 mol L-1 for omethoate. The BECS was applied to detection of methamidophos and omethoate in spiked kidney bean and cucumber samples with recoveries ranging from 88.2-96.9 %, and relative standard deviations of 2.10-4.10%. |
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