The Development Of Electrochemical Sensors Modified By Nanogold As Well As Graphene And Their Application On Pesticide Residues

Due to the overuse of pesticides, pesticide residues, which can accumulate in the humanbody through the food chain resulting in acute or chronic intoxication, has attracted theattention of the general public. Although traditional detecting methods has been widelyapplied on pesticide residues, they cannot meet current needs for their long time consuming,low sensitivity, expensive instruments and professional performance. Therefore, it is of greatsignificance to develop rapid, sensitive, credible and convenient detecting methods. Theelectrochemical method has caught research worker’s eyes among the novel detectingmethods owing to its high sensitivity, low cost, rapid and diversification. To achieve the aimof rapid, ultrasensitive and convenient detection on pesticide, the following work based onelectrochemical method and composite films sensitived by nanomaterials had been carriedout:Firstly, a novel electrochemical biosensor has been developed through one-stepelectrodeposition method with the potential parameter of-3.0V and time parameter of30min.The3D porous structure of calcium carbonate microparticle provides a favorable matrix toimmobilize AChE. When using the prepared biosensor to detect dimethoate, the linear wasbetween0.064~100ng/mL with a detection limit of3.2pg/mL. The detection process can beaccomplished within7min.Secondly, a new biosensor based on PSS-G/chitosan composite film was prepared. Thenew nanomaterial poly (sodium4-styrenesulfonate) functionalized graphene was synthesizedand characterized. After mixing the PSS-G with chitosan solution, the compound was used tomodify a glassy electrode to form a film, which can entrap AChE. What’s more, theapplication of graphene can not only adsorb AChE, but also accelerate the electron. Whenusing the biosensor to detect methyl parathion, the linear was between0.01~100ng/mL with adetection limition of5pg/mL.Finally, a novel ECL sensor based on PSS-G film was developed. Owing to the highion-exchange capcity of PSS, the luminescent reagent was immobilized on the electrodesurface. In addition, little PVA solution was compound with PSS-G to improve the stability ofthe film. According to the principle that tertiary amino groups can enhance thechemiluminescene intensity, the prepared sensor was used to detect pirimicarb, imidaclopridand acetamiprid. The detection limits were0.667ng/mL，40ng/mL，50ng/mL...