| Pesticides are important weapons for controlling pests and diseases,and are also important production materials for stabilizing food production.However,long-term misuse and illegal use of pesticides have seriously threatened the ecological environment and human health.Therefore,the development of a rapid,sensitive,convenient and reliable pesticide residue detection method has become an urgent and important research topic.The electrochemical sensor has become one of the most effective methods for detection of pesticide residues due to its fast,sensitive,convenient and reliable,low cost and many other advantages.The working electrode is one of the core components of the electrochemical sensor.However,the traditional glassy carbon electrode and metal electrode have low electrocatalytic activity,poor selectivity and low responsivity,which are far from satisfying the rapid detection requirements of pesticide residues.Low-dimensional carbon nanomaterials have the advantages of unique structure,excellent physical and chemical properties,large specific surface area,etc.,and have shown great potential for application development.This paper intends to combine low-dimensional nanotechnology,electrochemical sensing technology,molecular imprinting technology and other effective means.Two reliable,rapid and sensitive new electrochemical sensors were constructed to establish an electrochemical sensing method based on the detection of methyl parathion and cypermethrin residues.Based on the above research ideas,the research content of this paper is as follows?1?GONRs were prepared by KMnO4 oxidation cleavage method using MWCNTs as raw materials.The structure of GONRs was characterized by FTIR and Raman spectra.The GONRs-GCE modified electrode was fabricated by multi-potential step deposition method.The GONRs-GCE electrochemical sensor was constructed.The effects of methyl parathion concentration,scanning rate and buffer solution pH on sensor sensitivity were investigated by means of CV and SWV.The stability and reproducibility of the sensor were investigated.Under the optimum test conditions,the concentration of methyl parathion in the range of 3.0×10-71.0×10-6mol/L and 1.0×10-64.0×10-5 mol/L showed a good linear relationship with the response current?i?.The minimum detection limit was 1.6×10-8 mol/L,the actual sample detection recovery rate is 83.1%98.7%.The sensor has simple preparation method,low cost,fast and sensitive,and has potential for development and application.?2?The hBN-GCE modified electrode was prepared by drop coating method.The molecularly imprinted polymer film of cypermethrin was synthesized by electrochemical polymerization.The phase composition and surface structure of the polymer film were characterized by Raman and SPM.The template molecules were eluted by potentiostatic induction and the sensitivity of the sensor was evaluated by differential pulse voltammetry.Under the best test conditions,the sensor response current change value??i?has a good linear relationship with cypermethrin in the concentration range of 2.0×10-83.0×10-7 mol/L,and the detection limit is as low as8.5×10-9 mol/L,the average recovery of water sample spiked is between 96.3%and100.2%.The sensor has simple preparation,low detection cost,good stability and selectivity,and has good application prospect. |
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