The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported. The electrode can be used as a detector for the determination of dopamine with a hi...The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported. The electrode can be used as a detector for the determination of dopamine with a high stability and a good sensitivity. The cyclic voltammetric results indicated that there was a couple of well-defined redox peaks for dopamine at the PS/GC electrode with E_(pa)= 220 mV, E_(pc)=95 mV and the formal potential E^(o')= 157. 5 mV(vs. SCE) at 100 mV/s in the buffer solution of pH 7. 0. The PS/GC electrode can also be used to separate the electrochemical responses of ascorbic acid and DA by 54 mV with the differential pulse voltammetry. Under the selected conditions, the oxidation peak currents are linear with DA concetration in the range of 5. 0 × 10^(-6) to 5. 0 × 10^(-4) mol/L, and the detection limit is 1. 0 ×10^(-6) mol/L at S/N=3. Normalized with concentration, the relative sensitivity of dopamine to ascorbic acid reaches ca. 30. 8: 1.展开更多
Electrochemical oxidation reactions of L ascorbic acid(AA) at a copper cobalt hexacyanoferrate modified electrode(CoCuHCF/Pt) in neutral solutions were studied in comparison with that at a bared Pt electrode by in sit...Electrochemical oxidation reactions of L ascorbic acid(AA) at a copper cobalt hexacyanoferrate modified electrode(CoCuHCF/Pt) in neutral solutions were studied in comparison with that at a bared Pt electrode by in situ FTIR reflection absorption spectroscopy(FTIRRAS). The results indicated that the electrode oxidation of AA at both the electrodes CoCuHCF followed by chemical processes. AA is oxidized to dehydro L ascorbic acid(DHA) followed by a chemical hydration process. At Pt electrode, the DHA underwent hydration reaction to form bicyclic product, which then further was transformed into 2,3 diketogulonic acid and its enol form via an opening of lactone ring. However, at CoCuHCF/Pt electrode, the DHA undergoes ring opening reaction and then degradation reaction.展开更多
基金the National Natural Science Foundation of China
文摘The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported. The electrode can be used as a detector for the determination of dopamine with a high stability and a good sensitivity. The cyclic voltammetric results indicated that there was a couple of well-defined redox peaks for dopamine at the PS/GC electrode with E_(pa)= 220 mV, E_(pc)=95 mV and the formal potential E^(o')= 157. 5 mV(vs. SCE) at 100 mV/s in the buffer solution of pH 7. 0. The PS/GC electrode can also be used to separate the electrochemical responses of ascorbic acid and DA by 54 mV with the differential pulse voltammetry. Under the selected conditions, the oxidation peak currents are linear with DA concetration in the range of 5. 0 × 10^(-6) to 5. 0 × 10^(-4) mol/L, and the detection limit is 1. 0 ×10^(-6) mol/L at S/N=3. Normalized with concentration, the relative sensitivity of dopamine to ascorbic acid reaches ca. 30. 8: 1.
文摘Electrochemical oxidation reactions of L ascorbic acid(AA) at a copper cobalt hexacyanoferrate modified electrode(CoCuHCF/Pt) in neutral solutions were studied in comparison with that at a bared Pt electrode by in situ FTIR reflection absorption spectroscopy(FTIRRAS). The results indicated that the electrode oxidation of AA at both the electrodes CoCuHCF followed by chemical processes. AA is oxidized to dehydro L ascorbic acid(DHA) followed by a chemical hydration process. At Pt electrode, the DHA underwent hydration reaction to form bicyclic product, which then further was transformed into 2,3 diketogulonic acid and its enol form via an opening of lactone ring. However, at CoCuHCF/Pt electrode, the DHA undergoes ring opening reaction and then degradation reaction.
