| Since1970s, Ultramicroelectrodes （UME） have played an important role in theanalysis of environment, materials science, biology science and many otherfileds,becoming one of the most widest fields which are being researched. Havingsmall diameter, high current density and small iR drop, ultramicroelectrodes aresuitable for using as electrochemical transducer and scanning electrochemicalmicroscopy probe. Ultramicroelectrodes are convenient for us to research thosematerials at the microscopic level by kinetic and thermodynamic methods moredeeply, in addition ultramicroelectrodes also provide methods and means for ourdetection of micro and trace materials. Study on ultramicroelectrodes’ uniqueelectrochemical characteristics, not only has important significance in theelectrochemical sensing, polymerization, capillary electrophoresis, flow injectionanalysis, but also strengthens the relationship between electrochemical and otherdisciplines, making the electrochemistry infiltration to the energy, environment,materials and other high-tech fields.Carbon nanotubes （CNT） since its discovery, it has attracted strong attention.Since have unique structure, large specific surface area, good electrical conductivityand mechanical strength, carbon nanotubes has been widely used in physicalchemistry, material chemistry and other fields, having became one of the researchhotspots. In addition, because of the thermodynamic properties of carbon nanotubes isperfect, and it has a unique hollow channel structure, carbon nanotubes have alsoplayed an important role in modified electrode, catalyst carrier and many other fields.It is worth paying special attention that, carbon nanotubes may doped with many impurities in the preparation process, the impurities must be removed and carbonnanotubes should be purificated in order to maintain the property of carbonnanotubes.Determination of the content of heavy metals in water and the content ofmetronidazole in drugs has become one of the hotspots in electroanalytical chemistrypractical determination. The reason is that trace concentrations of heavy metals can beultimately delivered to the human body through contaminated those heavy metalsplant or animal body, and cause great harm to the human health. Metronidazole is akind of drug for the treatment of anaerobic infections, and clinical trial has prove that,once metronidazole’ content exceeds the standard value, this will cause the risk ofcancer. In this paper, different electrochemical sensors were prepared byelectrochemical polymerization and coating, thereby detecting of heavy metal ionsand metronidazole respectively, in specific work, it was divided into the followingtwo parts:First, fabrication of mercury-bismuth/carbon fiber ultramicroelectrode usingelectrochemical deposition means, then comparison to mercury/microelectrode,bismuth/microelectrode, mercury-bismuth/microelectrode and bare microelectrodeaccording to the performance of electrochemical behavior, optimization theexperimental conditions, and study of the new sensor’ behavior on lead, cadmiumcontent detection in tap water. The experimental results show that, theultramicromodified electrode has very good electro catalytic effect on lead andcadmium ion. In PH4.5acetic acid buffer solution, there appeared two peaks,-0.540Vfor Pb （II） and the-0.715V for Cd （II）,respectively. In0.4gL-1to3.2g L-1rangethe calibration curve equation and correlation coefficient of Pb （II） and Cd （II） are y=1.90x+0.39, r=0.999and y=0.66x+0.19, r=0.998. Detection limits Pb （II） andCd （II） were0.22g L-1and0.05g L-1（S/N=3）. Lead and cadmium content in water,were1.36+0.24gL-1and0.93+0.16gL–1though the ultramicro modified electrodedetection, the result are consistent with the results of using graphite furnace atomicabsorption method. Second, modification a layer of copper chloride doped multi walled carbonnanotubes film on glassy carbon electrode surface by using electrochemical coatingmethod in order to prepare CuCl2-MWCNT/GCE. The electrode was investigated bySEM and impedance spectroscopic characterization. By cyclic voltammetry scan rate,study the effect of pH and electrolyte membrane solution concentration on theCuCl2-MWCNT/GCE electrode electrochemical behavior, and comparison of theelectrochemical behavior differences between CuCl2-MWCNT/GCE and MWCNT/GCE and GCE, and then study the catalytic activity of CuCl2-MWCNT/GCE on themetronidazole. In the PH9.0BR buffer solution, the peak current and concentration ofmetronidazole are linear correlation, linear equation was Ip （A）=2.01×10-6+2.07C（M）, correlation coefficient r=0.9955, a detection limit of2×10-8M,.Comparedwith GCE, the electrochemical reaction of CuCl2-MWCNT/GCE on metronidazoleincreased apparently, and sensitivity and reproducibility were also greatly enhanced. |
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