Studies On The Adsorption Catalytic Voltammetry Of Organic Drugs And Electrochemical Studies Of Interaction Between Anti-cancer Drugs And DNA At Carbon Paste Electrodes

In this paper, a new kind of adsorptive catalytic voltammetry at carbon paste electrode (CPE) in the presence of dissolved oxygen was developed. The voltammetric behavior of organic drug (Physcion, Vitamin K3, Adriamycin, Daunorubicin) was studied by the proposed method. Adsorptive catalytic voltammetry plays an important role in both improving analysis sensitivity and studying kinetic of electrode process. A new approach is provided for determination of organic pharmacy by electrochemical analysis. The dissertation consists of four chapters. In chapter one, a novel electroanalytical method for the determination of physcion was described for the first time. Experiment found that physcion yields an adsorption catalytic voltammetric peak at –0.74 V (vs. SCE) in 0.4 mol/L NH₄Cl-NH₃·H₂O buffer solution (pH10.5) at a carbon paste electrode (CPE). The experiment results indicated that physcion was efficiently accumulated at a CPE by adsorption. In the following potential scan, physcion was reduced to homologous anthrahydroquinone compound, then the compound was immediately oxidized to physcion by dissolved oxygen in the solution, and then physcion was again reduced at the CPE. As a result, a cyclic catalytic reaction was established. The second-order derivative peak current is proportional to the physcion concentration in the range of 2.0×10^-10 to 4.0×10^-9 mol/L (accumulation 90 s) and 4.0×10^-9 to 2.0×10^-8 mol/L (accumulation 60 s). The limit of detection is 6.0×10^-11 mol/L (S/N=3) for 120 s accumulation time. The voltammetric behavior of physcion at a CPE was studied by cyclic voltammetry. The method was applied to the direct determination of physcion in medicinal plant polygonum multiflorum thumb with satisfactory results. In chapter two, a novel electroanalytical method was investigated for the determination of vitamin K3. The effective factors on the system were investigated, and a new method for the determination of vitamin K3 was established. And the oxidant is dissolved oxygen in the system. In 0.30 M NH3.H2O-NH4Cl buffer (pH 8.2), 0.0 V accumulation potential was applied to a carbon paste electrode for 60 s, and the 2nd–order derivate voltammogrames were recorded by applying a negative–going potential scan from 0.0 to –1.0 V at 400 mV/s. The peak current is linearly proportional to the vitamin K3 concentration in the range of 5×10-10 mol/L ～1.0×10-8 mol/L (accumulation 90s) and 1.0×10-8 mol/L ～2.5×10-7 mol/L (accumulation 60s) with the correlation coefficient of 0.9941 and 0.9972. The limit of detection is 1.5×10-10 mol/L for 90 s accumulation. The voltammetric behavior of vitamin K3 at a CPE was studied by cyclic voltammetry. The method was applied to the direct determination of vitamin K3 in clinical injection samples with satisfactory results. In chapter three, a novel electroanalytical method has been described for the first time to the determination of adriamycin. Experiment found that adriamycin yields an adsorption catalytic voltammetric peak in 0.10 mol/L H3BO3-Na2BO7 buffer solution (pH 8.5) at a carbon paste electrode (CPE). The second-order derivative peak current is proportional to the adriamycin concentration in the range of 1.7×10-11～3.4×10-9 mol/L (accumulation 180 s) and 3.4×10-9～6.9×10-8 mol/L (accumulation 120 s) with the correlation coefficient of 0.9979 and 0.9986. The limit of detection is 6.9×10-12 mol/L for 240 s accumulation. The proposed method was applied to direct determination of trace adriamycin in clinical injection samples. The result was in good agreement with the standard. The voltammetric behavior of adriamycin at a CPE was studied by cyclic voltammetry. The electrochemical character of adriamycin-DNA system was investigated by cyclic voltammetry and UV-Vis spectrum.In chapter four, a new adsorptive catalytic voltammetry was developed for the determination of daunorubicin at a CPE in the current paper and the oxidant of the reaction is dissolved oxygen. Experiment found that daunorubicin yields an adsorption catalytic voltammetric peak in 0.16 mol/L H3BO3-Na2B4O7-NaOH buffer solution (pH 10.5) at a carbon paste electrode (CPE). The second-order derivative peak current is proportional to the daunorubicin concentration in the range of 2.84×10-11～5.68×10-9 mol/L (accumulation 180 s) and 5.68×10-9～2.84×10-8 mol/L (accumulation 120 s) with the correlation coefficient of 0.9963 and 0.9987. The limit of detection is 1×10-11 mol/L for 180 s accumulations. The proposed method was applied to direct determination of trace daunorubicin in clinical injection samples. The result was in good agreement with the standard. The voltammetric behavior of daunorubicin at a CPE was studied by cyclic voltammetry. The electrochemical character of daunorubicin-DNA system was investigated by cyclic voltammetry and UV-Vis spectrum. From the above, adsorptive catalytic voltametry have very high sensitivity. And it is the development of polarographic catalytic wave, the selectivity, sensitivity of the methods can be improved further by choice and devising reasonably work electrode. The adsorptive catalytic voltammetric characteristics of pharmacy at solid electrode and the mechanism of electrode reaction will be studied further. Research on adsorptive catalytic voltammetry of organic drugs is of great significance for electroanalytical chemistry, biochemistry, organic chemistry and pharmacology.