A novel method was described for the determination of ultra trace amount of scandium based on the cathodic adsorptive voltammetry of the mix-polynuclear complex of scandium-calcium-alizarin red S at a carbon paste ele...A novel method was described for the determination of ultra trace amount of scandium based on the cathodic adsorptive voltammetry of the mix-polynuclear complex of scandium-calcium-alizarin red S at a carbon paste electrode (CPE). The 2nd-order derivative linear scan voltammograms of the adsorbed complex were recorded by model JP-303 polarographic analyzer from 0.0 to -1.0 V (vs. SCE). The experimental conditions of the working procedure were optimized. The results show that the complex can be adsorbed on the surface of the CPE, yielding one peak at -0.61 V, corresponding to the reduction of the alizarin red S in the mix-polynuclear complex at the electrode. The detection limit of Sc^(3+) is 1.0×10^(-10) mol·L^(-1) for 3 min of accumulation time. The procedure was successfully applied to the determination of trace amount of scandium in the sample ores.展开更多
New adsorptive anodic differential pulse stripping voltammetry method for the direct determination of morphine at trace levels in human plasma of addicts is proposed.The procedure involves an adsorptive accumulation o...New adsorptive anodic differential pulse stripping voltammetry method for the direct determination of morphine at trace levels in human plasma of addicts is proposed.The procedure involves an adsorptive accumulation of morphine on a HMDE,followed by oxidation of adsorbed morphine by voltammetry scan using differential pulse modulation.The optimum conditions for the analysis of morphine are pH 10.5,Eacc of -100 mV（vs.Ag/AgCl）,and tacc of 120 s.The peak current is proportional to the concentration of morphine,and a Linear calibration graph is obtained at 0.01-3.10μg mL^-1.A relative standard deviation of 1.06%（n=5）was obtained,and the limit of detection was 3 ng mL^-1.The capabiLity of the method for the analysis of real samples was evaluated by the determination of morphine in spiked human plasma and addicts human plasma with satisfactory results.展开更多
In Britton-Robinson buffer,metronidazole is preconcentreted on HHDE at 0.0 V(Vs.Ag- AgCI),An adsorptive stripping peak is observed at-0.62 V.Tho response is linear from 1x10^(-8)to 1×10^(-6)mol/L with 1.5 min acc...In Britton-Robinson buffer,metronidazole is preconcentreted on HHDE at 0.0 V(Vs.Ag- AgCI),An adsorptive stripping peak is observed at-0.62 V.Tho response is linear from 1x10^(-8)to 1×10^(-6)mol/L with 1.5 min accumulation.The method has been successfully applied to the deternation of metronidazole in human serum and formulations.展开更多
Anodic behavior of aripiprazole(ARP) was studied using electrochemical methods.Charge transfer,diffusion and surface coverage coefcients of adsorbed molecules and the number of electrons transferred in electrode mecha...Anodic behavior of aripiprazole(ARP) was studied using electrochemical methods.Charge transfer,diffusion and surface coverage coefcients of adsorbed molecules and the number of electrons transferred in electrode mechanisms were calculated for quasi-reversible and adsorp-tion-controlled electrochemical oxidation of ARP at 1.15 V versus Ag/AgCl at pH 4.0 in Britton-Robinson buffer(BR) on glassy carbon electrode.Voltammetric methods for direct determination of ARP in pharmaceutical dosage forms and biological samples were developed.Linearity range is found as from 11.4 μM(5.11 mg/L) to 157 μM(70.41 mg/L) without stripping mode and it is found as from 0.221 μM(0.10 mg/L) to 13.6 μM(6.10 mg/L) with stripping mode.Limit of detection(LOD) was found to be 0.11 μM(0.05 mg/L) in stripping voltammetry.Methods were successfully applied to assay the drug in tablets,human serum and human urine with good recoveries between 95.0% and 104.6% with relative standard deviation less than 10%.展开更多
Voltammetry using solid electrodes usually suffers from the contamination due to the deposition of the redox products of analytes on the electrode surface. The contamination has resulted in poor reproducibility and ov...Voltammetry using solid electrodes usually suffers from the contamination due to the deposition of the redox products of analytes on the electrode surface. The contamination has resulted in poor reproducibility and overelaborate operation procedures. The use of the chemical catalysis of oxidant on the reduction product of analyte not only can eliminate the contamination of analyte to solid electrodes but also can improve the faradaic response of analyte. This work introduced both the catalysis of oxidant K2S2O8 and the enhancement of surfactant Triton X-100 on the faraday response of amiodarone into an adsorptive stripping voltammetry at a carbon paste electrode for the determination of amiodarone. The method exhibits high sensitivity, good reproducibility and simple operation procedure. In 0.2 mol·L^-1 HOAc-NaOAc buffer （pH=5.3） containing 2.2×10^-2 mol·L^-1 K2S2O8 and 0.002% Triton X-100, the 2.5th-order derivative stripping peak current of the catalytic wave at 0.3 V （vs. Ag/AgCl） is rectilinear to amiodarone concentration in the range of 2.0×10^-10-2.3×10^-8 mol·L^-1 with a detection limit of 1.5×10^-10 mol·L^-1 after accumulation at 0 V for 30 s.展开更多
文摘A novel method was described for the determination of ultra trace amount of scandium based on the cathodic adsorptive voltammetry of the mix-polynuclear complex of scandium-calcium-alizarin red S at a carbon paste electrode (CPE). The 2nd-order derivative linear scan voltammograms of the adsorbed complex were recorded by model JP-303 polarographic analyzer from 0.0 to -1.0 V (vs. SCE). The experimental conditions of the working procedure were optimized. The results show that the complex can be adsorbed on the surface of the CPE, yielding one peak at -0.61 V, corresponding to the reduction of the alizarin red S in the mix-polynuclear complex at the electrode. The detection limit of Sc^(3+) is 1.0×10^(-10) mol·L^(-1) for 3 min of accumulation time. The procedure was successfully applied to the determination of trace amount of scandium in the sample ores.
文摘New adsorptive anodic differential pulse stripping voltammetry method for the direct determination of morphine at trace levels in human plasma of addicts is proposed.The procedure involves an adsorptive accumulation of morphine on a HMDE,followed by oxidation of adsorbed morphine by voltammetry scan using differential pulse modulation.The optimum conditions for the analysis of morphine are pH 10.5,Eacc of -100 mV（vs.Ag/AgCl）,and tacc of 120 s.The peak current is proportional to the concentration of morphine,and a Linear calibration graph is obtained at 0.01-3.10μg mL^-1.A relative standard deviation of 1.06%（n=5）was obtained,and the limit of detection was 3 ng mL^-1.The capabiLity of the method for the analysis of real samples was evaluated by the determination of morphine in spiked human plasma and addicts human plasma with satisfactory results.
文摘In Britton-Robinson buffer,metronidazole is preconcentreted on HHDE at 0.0 V(Vs.Ag- AgCI),An adsorptive stripping peak is observed at-0.62 V.Tho response is linear from 1x10^(-8)to 1×10^(-6)mol/L with 1.5 min accumulation.The method has been successfully applied to the deternation of metronidazole in human serum and formulations.
基金Scientific Research Unit of Ankara University forfinancial support with Grant number:11B4240005
文摘Anodic behavior of aripiprazole(ARP) was studied using electrochemical methods.Charge transfer,diffusion and surface coverage coefcients of adsorbed molecules and the number of electrons transferred in electrode mechanisms were calculated for quasi-reversible and adsorp-tion-controlled electrochemical oxidation of ARP at 1.15 V versus Ag/AgCl at pH 4.0 in Britton-Robinson buffer(BR) on glassy carbon electrode.Voltammetric methods for direct determination of ARP in pharmaceutical dosage forms and biological samples were developed.Linearity range is found as from 11.4 μM(5.11 mg/L) to 157 μM(70.41 mg/L) without stripping mode and it is found as from 0.221 μM(0.10 mg/L) to 13.6 μM(6.10 mg/L) with stripping mode.Limit of detection(LOD) was found to be 0.11 μM(0.05 mg/L) in stripping voltammetry.Methods were successfully applied to assay the drug in tablets,human serum and human urine with good recoveries between 95.0% and 104.6% with relative standard deviation less than 10%.
基金Project supported by the National Natural Science Foundation of China （No. 20475043）.
文摘Voltammetry using solid electrodes usually suffers from the contamination due to the deposition of the redox products of analytes on the electrode surface. The contamination has resulted in poor reproducibility and overelaborate operation procedures. The use of the chemical catalysis of oxidant on the reduction product of analyte not only can eliminate the contamination of analyte to solid electrodes but also can improve the faradaic response of analyte. This work introduced both the catalysis of oxidant K2S2O8 and the enhancement of surfactant Triton X-100 on the faraday response of amiodarone into an adsorptive stripping voltammetry at a carbon paste electrode for the determination of amiodarone. The method exhibits high sensitivity, good reproducibility and simple operation procedure. In 0.2 mol·L^-1 HOAc-NaOAc buffer （pH=5.3） containing 2.2×10^-2 mol·L^-1 K2S2O8 and 0.002% Triton X-100, the 2.5th-order derivative stripping peak current of the catalytic wave at 0.3 V （vs. Ag/AgCl） is rectilinear to amiodarone concentration in the range of 2.0×10^-10-2.3×10^-8 mol·L^-1 with a detection limit of 1.5×10^-10 mol·L^-1 after accumulation at 0 V for 30 s.
