| This thesis studied the preparation,voltammetric behavior and electroanalytical application of the modified PB-Eu composite mercury film electrode (PB-Eu/MFE) on glass carbon substrate. The main aim of this paper was not only prepare PB-Eu/MFE by means of electrodeposition of mercury on PB-Eu/GCE, but also extend applied field for inorganic polynuclear transition metal-hexacyanometallate film modified electrode.The PB-Eu/MFE was successfully applied to determine trace levels of lead in environmental water samples by differential pulse anodic stripping voltammetry and tinidazole in tablets and injections by square wave voltammetry. The PB-Eu/MFE remarkably showed higher sensitivity, perfect stability, long-lived and good repeatability and also had more and more potential application in the field of electroanalysis futurely. This paper consisted of three parts: Part one: IntroductionA review has been made for the types, history of the development, and dominating problem of conventional mercury film electrode. The development trend, type, preparation, application of mercury film electrode, especially chemically modified composite mercury film electrode were simply discussed. Furthermore, this part summarized the structure, preparation, characteristics and applications of the chemically modified composite electrode coated with PB analogue and its evolution of electroanalytical application was concluded in detail. In addition, the future prospects of the chemically modified composite electrode coated with PB material were outlined. 128 references were cited. Part two: Study on the preparation and voltammetric property of the PB-Eu/MFEThe several conditions of preparing PB-Eu/MFE containing PB-Eu film composition, end capping before plating mercury and potential range were completely investigated by Pb2+ as probe ion. Furthermore, the overvoltage value for hydrogen formation and the effect of surfactant at the PB-Eu/MFE and its stability were studied using Zn2+ as probe ion. The results showed the molar ratio of the PB-Eu film modified solution was given to be 1:1:2:1 for K3Fe(CN)6:FeCl3:Eu3+:o-C6H4(COO)2HK. The PB-Eu/GCE was activated in 0.1mol/LK2SO4, then was capped in 1ml 1×10-5mol/L KSCN +0.1mol/L KC1 7.5 ml+0.1mol/L HC1 mixed solution (pH=2.4). PB-Eu/MFE was prepared in cell contained Hg(NO3)2, KC1, NH4Ac,HAc(pH=2.0) by electrodeposition. The overvoltage value for hydrogen formation atPB-Eu/MFE in strong acid exceeded -1.2V. The PB-Eu/MFE had better capability to resist theinterference of the surface active compounds than the GCE/MFE.Part three: Study on application of the PB-Eu composite mercury film electrodeThis Part included two chapters:Chapter 1 Determination of trace lead in environmental water by differential pulseanodic stripping voltammetry on PB-Eu/MFETrace levels of lead in environmental water samples were determined by differential pulse anodic stripping voltammetry using the PB-Eu/MFE as working electrode. The results revealed a stripping peak of lead at -0.472 V (vs SCE) in 0.01 mol/L HNO3. Good linearity was obtained in the concentration range of 0.8～250μg/L(r=0.9995, n=12) with a detection limit of 0.2μg/L (S/N=3) under the optimum conditions. This method was successfully used for the determination of lead in four different environmental water samples. The average rates of recoveries of the method were 97-104.5%, RSD were 2.46-3.18%. Indeed, compared to literatures, perfect stability, shorter accumulation time were observed using PB-Eu/MFE. Chapter 2 Determination of tinidazole by square wave voltammetry on PB-Eu/MFEThe electrochemical behavior of tinidazole has been studied at a PB-Eu/MFE using cyclic voltammetric in BR buffer solution(pH=6.0). A reduction peak potential of tinidazole was observed at -0.558 V (vs SCE). The adsorption characteristic of tinidazole at PB-Eu/MFE was discussed. Good linearity was obtained respectively in the concentration range of 2.5×10-6～5.0×l0-4 and 2.5×l0-8～7.5×l0-7mol/L with a detection limit of 2.0×l0-9 mol/L(S/N=3) under the optimum conditions. This method was used for the determination of tinidazole in tablets and injections with excellent results. |
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