Studies On Nanomaterial And Bismuth Film Modified Glassy Carbon Electrode And Its Application

Nanomaterials display size-dependent optical,magnetic,electronic,chemical properties,and these physical and chemical properties greatly differ from the bulk substances.Nanomaterials can act as electrode matertials,and chemically modified electrodes have the extraordinarily chemical and electronic properties to improve the selectivity and sensitivity.Carbon nanotubes(CNTs) are arrangements of carbon hexagons that are formed into tiny tubes,and both ends of each single tube are closed with caps formed by carbon rings.The extraordinarily electronic property of CNTs enables them to facilitate the electron transfer when they act as electrode materials.Furthermore,the properties include excellent adsorption capability,large specific surface and various functional groups linked on CNTs have endued them with special electrocatalytic effect to the electrochemical behavior of some species.Zirconia(ZrO₂) is an inorganic oxide with thermal stability,chemical inertness,lack of toxicity.And ZrO₂ nanoparticles are highly conductive and they usually served as electrocatalytic activity nanomaterials for electrochemical detection.Researchers have demonstrated that zirconia has strong affinity for phosphoric group,which motivates us using ZrO₂ nanoparticles as selective sorbents for solid-phase extraction(SPE) of organophosphate pesticides(OPs) and their detection.Bismuth-film electrodes(BiFEs) have become an attractive new subject of electroanalytical research as a potential replacement for common mercury-based electrodes.BiFEs can be prepared by depositing thin bismuth films on suitable substrates, and they have two main advantages:their environmental friendly nature and an electrochemically renewable electrode surface.The area in which BiFEs find most applications is trace metal analysis.However,only few reports have focused on determination of organic compounds using BiFEs.In order to rapidly detect OPs and Sudan I,we have prepared three modified electrodes:(1) ZrO₂ nanoparticles modified glassy carbon electrode(GCE):The promising SPE and stripping voltammetric performances open new opportunities for fast,simple,and sensitive analysis of OPs. (2) MWCNT-Ag nanocomposites modified GCE:We have explored a new strategy to deposit Ag nanoparticles(AgNPs) on the side wall of MWCNTs as mulitwalled carbon nanotube/silver(MWCNT-Ag) nanocomposites,by one step reaction of Sudan I with AgNO₃ at the room temperature.MWCNT-Ag nanocomposites could be incorporated into the electrochemical system to facilitate the electron exchange between the electrode and the electrochemical probe due to the enhanced conductivity of the matrices.[Fe(CN)₆]^3-/4- redox system was used as a probe to indicate the process of electron transfer across the interface and also analyze sudan I quantitatively.And we also can detecte indirectly Sudan I based on a stripping analysis of the formation of AgNPs.(3) Bismuth film modified GCE(BiF/GCE):On the one hand,we used BiF/GCE for the directly cathodic electrochemical detection of some electroactive organophosphate pesticides.On the other hand,Sudan I can strongly adsorb onto BiF/GCE surface. Therefore,an electrochemical sensor for sudan I based on SPE at BiF/GCE was developed.In this paper,the combination of nanomaterials to bismuth film,modified electrodes, SPE and electrochemical sensors allows fast,sensitive,and selective determination of OPs and Sudan I.And the proposed methods are thus expected to open new opportunities for detecting other environmental and food chain pollutants.