| The peroxy bond of dihydroartemisinin(DHA)is essential for it's antimalarial and antitumor activity. In order to understand the mechanism of antimalarial and antitumor, electrochemical method were used to study the interaction between DHA with Cu(Ⅱ) ion and Bi(Ⅲ) ion.At bare GC electrode and single-wall carbon nanotubes(SWNT) modified electrode, the electron transfer rate(α) of DHA was 0.57 and 0.76 respectively, while the apprarent rate constant(Ks) was 12.1s-1 and 31.7s-1 respectively. The result showed that single-wall carbon nanotubes could accelerate electron transfer, which would improve the analytical sensitivity.The interaction between DHA and Cu(Ⅱ) ion was studied by electrocheical method at single-wall carbon nanotubes modified GC electrode. With adding of Cu(Ⅱ) ion, the potential of DHA reduction peak shifted positively from -0.84V to -0.73V(vs.SCE), the cathodic overpotential of DHA lowed by 110mV, and the reduction activation energy of DHA decreased 21.23kJ/mol. The result showed that DHA could be catalyzed by Cu(Ⅱ) ion, catalytical mechanism between DHA and Cu(Ⅱ) be studied. The electro-catalytic degree by Cu(Ⅱ), Fe(Ⅲ) and heroin were compared, and showed that Cu(Ⅱ) ion has obvious electrocatalysis. Electrochemical studies showed that DHA and Cu(Ⅱ) ion system has a best catalytical effect when the concentration of DHA was 9.0×10-5mol/L, while the concentration of Cu(Ⅱ) ion was in the range of 1.0×10-5mol/L to 9.0×10-5mol/L. Both electrochemical and UV-vis spectroscopy methods showed that the binding ratio between DHA and Cu(Ⅱ) ion was 1:2.Electrocheical method was used to study the interaction between DHA and Bi(Ⅲ) ion. With adding of Bi(Ⅲ) ion, the potential of DHA reduction peak shifted positively from -0.84V to -0.71V, the cathodic overpotential of DHA lowed by 130mV, and the reduction activation energy of DHA decreased 25.09kJ/moL. The result also showed that DHA could be catalyzed by Bi(Ⅲ) ion. Catalytical mechanism between DHA and Bi(Ⅲ) be studied. The interaction between DHA and Bi(Ⅲ) ion also been studied. The result showed that DHA and Bi(Ⅲ) ion system has also a good catalytical effect when the concentration of DHA was 9.0×10-5mol/L, while the concentration of Bi(Ⅲ) ion was in the range of 1.0×10-5mol/L to 4.0×10-4mol/L. |
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