We previously reported the direct electrochemical detection of insulin at bare carbon electrodes. Here a novel modified acetylene carbon black paste electrode(SiC/CB-CPE), based on the outstanding characteristics of s...We previously reported the direct electrochemical detection of insulin at bare carbon electrodes. Here a novel modified acetylene carbon black paste electrode(SiC/CB-CPE), based on the outstanding characteristics of silicon carbide nanostructure,was developed for the electrooxidation of insulin in alkaline solution and it was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) in 5 mmol/L Fe(CN)63-/4- solution. It is found that silicon carbide nanostructure doped into the CB-CPE greatly facilitates the redox electrochemistry of Fe(CN)63-/4- probe and the electrochemical oxidation of insulin. The electrooxidation of insulin is a one-electron and one-proton reaction and an irreversible adsorption-controlled electrode process. The anodic oxidation current increases linearly with the concentration of insulin from 1×10-7mol/L to1.2×10-6mol/L in 0.1 mol/L Na2CO3-NaHCO3 buffer solution(pH 10.0) and the detection limit was 50 nmol/L. In addition, the SiC/CB-CPE shows good sensitivity, reproducibility, renewability and capacity of resisting disturbance.展开更多
A highly selective and rapid anodic adsorptive voltammetric method was developed for the （determination） of ultra trace amount of ofloxacin at a carbon paste electrode（CPE）. The ofloxacin adsorbed on the surface o...A highly selective and rapid anodic adsorptive voltammetric method was developed for the （determination） of ultra trace amount of ofloxacin at a carbon paste electrode（CPE）. The ofloxacin adsorbed on the surface of the CPE in a 0.096 mol/L KHP-NaOH buffer solution（pH=5.6） could produce one oxidation peak at 0.92 V（vs.SCE） when scanning was performed from 0.4 to 1.4 V. The relationship between the peak current and the ofloxacin concentration was linear in the ranges of 5.5×10-9～5.5×10-8 mol/L（75 s accumulation） and 3.3×10-8～3.3×10-7 mol/L（30 s accumulation）. The correlation coefficients were 0.996 and 0.998, respectively. Its detection limit was 9.0×10-10 mol/L（S/N=3） for 150 s accumulation. The （electrode） reaction mechanism of ofloxacin was investigated. The proposed method was applied to analyze trace ofloxacin in urine samples. The result was in good agreement with that obtained by spectrophotometry （determination）.展开更多
基金Funded by the Innovative Talent Training Project of Chongqing University(CDJXS11220004)the Fundamental Research Funds for the Central Universities of Chongqing University+1 种基金the Natural Science Foundation Project of CQ CSTC(No.2011BB5134)the National Natural Science Foundation of China(No.NSFC81101417)
文摘We previously reported the direct electrochemical detection of insulin at bare carbon electrodes. Here a novel modified acetylene carbon black paste electrode(SiC/CB-CPE), based on the outstanding characteristics of silicon carbide nanostructure,was developed for the electrooxidation of insulin in alkaline solution and it was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) in 5 mmol/L Fe(CN)63-/4- solution. It is found that silicon carbide nanostructure doped into the CB-CPE greatly facilitates the redox electrochemistry of Fe(CN)63-/4- probe and the electrochemical oxidation of insulin. The electrooxidation of insulin is a one-electron and one-proton reaction and an irreversible adsorption-controlled electrode process. The anodic oxidation current increases linearly with the concentration of insulin from 1×10-7mol/L to1.2×10-6mol/L in 0.1 mol/L Na2CO3-NaHCO3 buffer solution(pH 10.0) and the detection limit was 50 nmol/L. In addition, the SiC/CB-CPE shows good sensitivity, reproducibility, renewability and capacity of resisting disturbance.
文摘A highly selective and rapid anodic adsorptive voltammetric method was developed for the （determination） of ultra trace amount of ofloxacin at a carbon paste electrode（CPE）. The ofloxacin adsorbed on the surface of the CPE in a 0.096 mol/L KHP-NaOH buffer solution（pH=5.6） could produce one oxidation peak at 0.92 V（vs.SCE） when scanning was performed from 0.4 to 1.4 V. The relationship between the peak current and the ofloxacin concentration was linear in the ranges of 5.5×10-9～5.5×10-8 mol/L（75 s accumulation） and 3.3×10-8～3.3×10-7 mol/L（30 s accumulation）. The correlation coefficients were 0.996 and 0.998, respectively. Its detection limit was 9.0×10-10 mol/L（S/N=3） for 150 s accumulation. The （electrode） reaction mechanism of ofloxacin was investigated. The proposed method was applied to analyze trace ofloxacin in urine samples. The result was in good agreement with that obtained by spectrophotometry （determination）.
