Interface Design Of Dye-based Polymer Modified Electrode And Determination Of Residual Organophosphorus Pesticide Content

Residual organophosphorus pesticides (OPs), which can cause an irreversible harm forhuman and animals’ health, are a large class of food and environmental pollutants. It is one of hotissues in the research field of food safety and environmental protect. In this thesis, three typies ofnanointerface were designed based on the electropolymerrized dye and/or nanomaterials filmmodified glassy carbon electrode. Then we used these modified electrodes to measure theparathion in aqueous and real cabbage samples due to their high specific surface area, goodconductivity, high sensitivity and some selectivity. The results are satisfactory. The detailedresearch is as follows:1． The studies for the determination of residual parathion based on the graphene film modifiedglassy carbon electrodeA graphene film modified glassy carbon electrode was prepared. The electrochemicalbehavior of parathion (PT) based on this electrode was studied by cyclic voltammetry in detail.The experimental conditions such as the supporting electrolyte and its pH were optimized. Theresults indicated that PT had a good electrochemical response at0.1mol/L of acetic acid-sodiumacetate buffer (pH5.0) at the surface of graphene film modified electrode. Compared with the bareelectrode, the redox peak current of parathion significantly improved and the redox peak potential was more shape, which showed that the graphene film has a catalytic role for the electrochemicalredox of parathion. The oxidation peak current of parathion was linear with its concentration in therange of1.0×10-7to1.0×10-6mol/L and in the range of3.0×10-6to1.0×10-5mol/L with their linearcorrelation coefficients of0.9847and0.9996, respectively. The detection limit was1.0×10-8mol/L(S/N=3). The modified electrode was applied to detect the content of residual parathion invegetables, the result was satisfactory.2. Determination of residual parathion in vegetables based on poly nile blue A/graphenecomposite film modified electrodeA poly Nile Blue A/graphene composite film modified glassy carbon electrode was prepared.The electrochemical behavior of parathion (PT) based on this electrode was studied by cyclicvoltammetry and square wave voltammetry in detail. The experimental conditions such as thesupporting electrolyte, its pH and accumulation time and other experimental conditions wereoptimized. The results indicated that PT had a good electrochemical response at0.1mol/L of citricacid-hydrochloric acid buffer (pH3.8). Compared with the bare glassy carbon electrode and themonolayer film modified electrode, the redox peak current of parathion significantly improvedand the redox peaks were much shaper, which showed that the complex film has a catalytic rolefor the electrochemical redox of parathion. The oxidation peak current of parathion was linearwith its concentration in the range of1.0×10-7~1.0×10-6mol/L with the linear correlationcoefficient of0.9920, the detection limit is1.0×10-7mol/L (S/N=3). The modified electrode wasapplied to detect the content of residual parathion in vegetables, the result was satisfactory.3. Vegetables Residue Determination of parathion poly crystal violet/acetylene black compositefilm modified electrodeTry a combination of four acetylene black and crystal violet into the film modified electrodes,respectively: acetylene black/poly crystal violet modified electrode, poly crystal violet/acetylene black modified electrode, acetylene black crystal violet composite electrode, acetyleneblack film modified electrode collaborative crystal violet, which coordinated acetylene black filmelectrode modified with crystal violet to focus the discussion. The modified membraneelectrochemical parathion sensitive response, but it is the synergy of crystal violet test solution of monomers, or promote changes in the pH of the resulting, pending further study.