| Carbon nanotube currently is one of the most popular nanomaterials because of its unique mechanical,electric and thermal properties.Based on its good conductivity,catalytic activity and large specific surface area,carbon nanotube is widely used the research of chemical modified electrode.At present,carbon nanotubes modified electrodes have been developed in electrocatalytic and electroseparation aspects,which especially achieved the obvious reduction of overpotential and direct electron transfer of oxidation-reduction reactions of some proteins.In this article,the electrochemical behaviours of ganciclovir and entecavir were investigated by using carbon nanotubes as electrode materials,and the human serum albumin biosensor was constructed and applied by the zero current potentiometry.The concrete contents are described as follows:Part one Documents reviewThis part focused on the present status and application of carbon nanotubes and carbon nanotubes modified electrodes in the field of electroanalytical chemistry.The discovery,the structure and the classification,the particular characteristics have been introduced,as well as the main preparation methods and the purification were enumerated.Finally,the application of carbon nanotubes modified electrodes in electrochemistry was reviewed emphatically.Part two The studies of the electrocatalysis of two nucleoside drugs at multiwalled carbon nanotube-intercalated thin film wax-impregnated graphite electrodeChapter one Electrocatalysis of ganciclovir oxidation at multiwalled carbon nanotube-intercalated thin film wax-impregnated graphite electrode and its applicationMultiwalled carbon nanotube-intercalated thin film wax-impregnated graphite electrode (MWNT-IWGE) exhibited more efficient electrocatalytic action toward the oxidation of ganciclovir(GCV).The electrocatalytic action was characterized by the further enhancement of oxidation peak current and the further reduction of oxidation peak potential of GCV comparing with those of other graphite electrodes,which resulted from not only MWNT properties but also MWNT form intercalated on substrate electrode.Based on these,a single-sweep voltammetric method for the determination of GCV was proposed.The oxidation peak current of GCV at 1.03 V(vs.SCE) in pH 5.9 HAc-NaAc buffer was rectilinear in the concentration range from 8.0×10-8 to 1.0×10-5 mol·L-1 in the case of accumulation at 0.5 V for 90 s.The limit of detection was 1×10-8 mol·L-1.In addition,the oxidation process of GCV was a two-electron and two-proton transfer,and took place at the C-8 position of its parent guanine.Chapter two Electrocatalytic oxidation of entecavir and its voltammetric determination at multiwalled carbon nanotube thin film-intercalated on wax-impregnated graphite electrodeThe electrochemical behavior of entecavir(ETV) at multiwalled carbon nanotube thin film-intercalated on wax-impregnated graphite electrode(MWNT-IWGE) was first investigated by using cyclic voltammetry and single-sweep voltammetry.The results indicated that MWNT-IWGE exhibited electrocatalytic action toward the oxidation of ETV, which was characterized by both the reduction of the oxidation peak potential of ETV by 60 mV and the marked enhancement of the oxidation peak current by 5 times,compared with those at bare wax-impregnated graphite electrode(WGE).Moreover,the oxidation process was a two-electron and two-proton transfer,resulting into the carbonylation of C-8 position in guanine ring of ETV.Consequently,a simple and sensitive voltammetric method for the determination of ETV was developed.With single-sweep voltammetry,a well-defined oxidation peak appeared at 1.13 V(vs.SCE) in 0.1 mol·L-1 HAc-NaAc buffer(pH 4.1).The oxidation peak current was proportional to ETV concentration from 1.0×10-7 to 8.0×10-6 mol·L-1.The limit of detection was 3×10-8 mol·L-1.Part three The electrochemical sensor based on a new type of carbon nanotubes electrode and its application Chapter one The MWNT sensor applied in the determination of human serum albumin using the zero current potentionmetryA novel method for fabrication of human serum albumin(HSA) biosensor prepared by direct fixing proper multiwalled carbon nanotube(MWNT) on gluey cellophane tape had been developed.According to the zero current potentionmetry,the I-Eapp curve and Ezcp was measured applied the linear sweep potential,and the quantitative analysis of HSA was calculated using the calibration curve obtained by plotting the Ezcp versus HSA concentration. The results showed that the limit of detection was 2×10-8 mol·L-1 and a linear relationship between the Ezcp and HSA concentration was found in the range of 2.8×10-8～3.4×10-7 mol·L-1.The MWNT sensor had relatively good selectivity and high stability,ascorbic acid, dopamine and common amino-acids did not interfere with the determination. |
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