The adsorptive and electrochemical behaviour of phoxim on a hanging mercury drop electrode were explored in NH3·H2O-NH4Cl buffer by using cyclic and linear sweep voltmmetry. The procedure was successfully applied...The adsorptive and electrochemical behaviour of phoxim on a hanging mercury drop electrode were explored in NH3·H2O-NH4Cl buffer by using cyclic and linear sweep voltmmetry. The procedure was successfully applied for the assay of phoxim in vegetable and fruit samples.展开更多
The presence of the pesticide ethion was determined using an electroanalytical method, i. e. , linear sweep stripping voltammetry at a hanging mercury drop electrode in the Britton-Robbinson buffer with pH = 8. 36, ba...The presence of the pesticide ethion was determined using an electroanalytical method, i. e. , linear sweep stripping voltammetry at a hanging mercury drop electrode in the Britton-Robbinson buffer with pH = 8. 36, based on its reduction peak observed at - 690 mV following its alkaline hydrolysis. The experimental parameters, namely, the preconcentration potential, the preconcentration time, and the scan rate were investigated and - 300 mV (vs. Ag/ AgCl), 270 s, and 100 mV/s were selected as the optimal values, respectively. The linear relationship between the peak current and the concentration was found to be in the range of 0.02-0. 16 mg/L, with a detection limit of 0.0087 mg/L. The proposed method was applied to the determination of ethion in spiked vegetable and fruit samples via a preextraction with anhydrous ethanol.展开更多
This paper reports the electrochemical properties of sulpiride at a mercury electrode, especially its adsorptive characteristic. Sulpiride dissolved in a supporting electrolyte of a McIlvaine buffer at pH 6 8 represe...This paper reports the electrochemical properties of sulpiride at a mercury electrode, especially its adsorptive characteristic. Sulpiride dissolved in a supporting electrolyte of a McIlvaine buffer at pH 6 8 represents a sensitive and well defined reduction wave by linear sweep stripping voltammetry. This method is based on the pre concentration and the reduction of sulpiride at a hung mercury drop electrode. The reduction peak potential is -1 72 V( vs . Ag AgCl) and the peak current is proportional to the concentration of sulpiride in the range of 0 1-0 6 μg/mL. The detection limit is 0 025 μg/mL obtained under the experimental conditions selected in this work. The electrochemical properties of this system were investigated, and the proposed method was applied to the determination of sulpiride in pharmaceutical tablets with satisfactory results. It was compared well with the UV spectrophotometric method, showing a superior sensitivity.展开更多
The redox behavior of spironolactone(SP) drug in Britton-Robinson(BR) buffer of pH 2-11 was investigated by differential pulse cathodic stripping voltammetry(DPCSV) and cyclic voltammetry(CV) at hanging mercur...The redox behavior of spironolactone(SP) drug in Britton-Robinson(BR) buffer of pH 2-11 was investigated by differential pulse cathodic stripping voltammetry(DPCSV) and cyclic voltammetry(CV) at hanging mercury dropping electrode(HMDE).At pH 9-10.5,the DPCSV of SP drug showed two cathodic peaks at1.15 and1.38 V at the HMDE vs.Ag/AgCl reference electrode.In the CV,at pH 9-10,the dependence of the cathodic peak current,Ip,c and peak potential,Ep,c of the second peak(Ep,c2) on the scan rate(n) and on the depolizer(SP) concentrations was typical of an electrode coupled(EC) chemical reaction type mechanism.The plot of Ip,cat 1.380 V of the DPCSV vs.SP concentration at pH 9 was linear over the concentration range of 1.2×1010-9.6×107 M.The lower limit of detection(LLOD) and limit of quantification(LOQ) of the drug were 1.1×1011 and 4.14×1011 M,respectively.The method was successfully applied for the analysis of SP residues in industrial wastewater,in pure form(98.273.1%) and in drug formulations e.g.Aldactones tablet(98.3572.9%).The method was validated by comparison with HPLC and the official data methods.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
A reliable method for simultaneous determination of three antibiotic drugs(levofloxacin,gatifloxacin and lomefloxacin) by differential pulse stripping voltammetry(DPSV) in Britton-Robinson buffer(pH 7.96) was pr...A reliable method for simultaneous determination of three antibiotic drugs(levofloxacin,gatifloxacin and lomefloxacin) by differential pulse stripping voltammetry(DPSV) in Britton-Robinson buffer(pH 7.96) was presented.The method is based on adsorptive accumulation of the antibacterial drugs on a hanging mercury dropping electrode(HMDE),followed by the reduction of the adsorptive species by the technique of DPSV.Optimal conditions,the deposition time of 80 s,the deposition potential of—1250 mV,and the scan rate of 25 mV/s,were obtained.The linear concentration ranges of 0.010-0.080μg/mL were obtained for all these three antibiotic drugs,while the detection limits were 2.38,3.20 and 1.60ng/mL for levofloxacin,gatifloxacin and lomefloxacin,respectively.In this work,chemometrics methods,such as classical least squares(CLS),partial least squares(PLS), principle component regression(PCR) and radial basis function-artificial neural networks(RBF-ANN),were used to quantitatively resolve the overlapping signals.It was found that PCR gave the best results with total relative prediction error(RPE_T) of 7.71%.The proposed method was applied to determine these three drugs in several commercial food samples with spiked method and yielded satisfactory recoveries.展开更多
An electrochemical flow device has been developed for the determination of heavy metal ions(HMI)in water using multiwalled carbon nanotubes(MWCNTs)/Nafion(NA)/Hg electrode,by mean of diff erential pulse anodic strippi...An electrochemical flow device has been developed for the determination of heavy metal ions(HMI)in water using multiwalled carbon nanotubes(MWCNTs)/Nafion(NA)/Hg electrode,by mean of diff erential pulse anodic stripping voltammetry coupled with sequential injection analysis.The accuracy of the determination was ensured by the great electrical conductivity of MWCNTs and the high adsorption capacity of Hg.NA was used for MWCNTs immobilization for the long-term application of the electrode.The mercury film was cleaned after determination and another one would form during deposition.A lower limit of detection and a wider determination range of Cd^(2+)and Pb^(2+)could be achieved using the automatically analytical device combining with the MWCNTs/NA/Hg-modified electrode.The real-time monitoring of Cd^(2+)and Pb^(2+)in fresh water using this device continued for 10 days.The results indicated that the method was potential for on-site and real-time determination of HMI in water samples.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
Poly(neutral red) film modified carbon fibre microelectrodes offer substantial improvement in voltammetric sensitivity and selectivity towards epinephrine (EP). The poly(neutral red) film was electropolymerized by cyc...Poly(neutral red) film modified carbon fibre microelectrodes offer substantial improvement in voltammetric sensitivity and selectivity towards epinephrine (EP). The poly(neutral red) film was electropolymerized by cycling the potential between -0.8 V and +0.8 V. The anodic stripping voltammetric response for EP was found to be dependent on accumulation time and potential. By using a poly(neutral red) film modified carbon fibre microelectrode with a 1 min preconcentration at -1.2 V in biological phosphate buffer solution (pH=7.4), a good linear relationship between the anodic stripping peak currents and EP concentrations was obtained in the range of 2.0×10 -7  ̄ 2.0×10 -5 mol/L. The detection limit was up to 9.0 ×10 -8 mol/L. Moreover, 400 times higher concentrations of vitamin C did not interfere with the measurement of EP. This method was used for determining EP concentrations in epinephrine hydrochloride injection solution with satisfactory results.展开更多
he present paper covers the construction and behaviour of a mixed binder car-bon paste electrode modified by surfactant system appropriate for the anodic strip-ping voltammetric quantitation of sulphadiazine. The mixe...he present paper covers the construction and behaviour of a mixed binder car-bon paste electrode modified by surfactant system appropriate for the anodic strip-ping voltammetric quantitation of sulphadiazine. The mixed binder consisted ofglycerol and liquid paraffin. On this electrode in a PH 8. 20 buffer solution sulpha-diazine yields a sensitive anodic stripping voltammetric wave at 0. 82 V. It can beused for the determination of trace amounts of drug, the linear range of the peakcurrent to the sulphadiazine concentration being from 1. 0 x 10-7 to 5. 0 x 10-5mol/L, and the detection limit being 6. 6 x 10-9 mol/L with a relative standard de-viation of 2. 6% (n= 15).The proposed method was used to determine the drug inurine samples.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
Differential pulse stripping voltammetry method(DPSV) was applied to the determination of three herbicides, ametryn, cyanatryn, and dimethametryn. It was found that their voltammograms overlapped strongly, and it is...Differential pulse stripping voltammetry method(DPSV) was applied to the determination of three herbicides, ametryn, cyanatryn, and dimethametryn. It was found that their voltammograms overlapped strongly, and it is difficult to determine these compounds individually from their mixtures. With the aid of chemometrics, classical least squares(CLS), principal component regression(PCR) and partial least squares(PLS), voltammogram resolution and quantitative analysis of the synthetic mixtures of the three compounds were successfully performed. The proposed method was also applied to the analysis of some real samples with satisfactory results.展开更多
A chitosan modified glassy carbon electrode(CMGCE) was employed for the determination of thiocyanate. The measurement was carried out by means of anodic stripping voltammetry. The effects of several experimental param...A chitosan modified glassy carbon electrode(CMGCE) was employed for the determination of thiocyanate. The measurement was carried out by means of anodic stripping voltammetry. The effects of several experimental parameters, such as pH, the amount of modifier, deposition potential and deposition time were studied for analytical application, respectively. A liner response was obtained in the concentration range of 3 5×10 -8 - 9.3×10 -7 g/mL of SCN -. The detection limit was found to be 1.9×10 -8 g/mL. The method was satisfactorily used to detect SCN - in saliva.展开更多
An electrochemical method for the simultaneous detection of two different DNA sequences from PAT and FMV 35S gene sequence using CdS and PbS quantum dots (QDs) as labels was described. The QDs were readily functiona...An electrochemical method for the simultaneous detection of two different DNA sequences from PAT and FMV 35S gene sequence using CdS and PbS quantum dots (QDs) as labels was described. The QDs were readily functionalized with oligonucleotides as electrochemical DNA probes and selectively hybridized to the complementary sequences immobilized on the microplate. The QDs anchored on the hybrids were dissolved in the solution by the oxidation of HNO3 and further detected by a sensitive differential pulse anodic stripping voltammetric method (DPASV). The DPASV signals of the oxidation of Cd^2+ and Pb^2+ ions present in the solution were different and reflected the identity of corresponding ssDNA targets sequences.展开更多
This paper covers the construction and behaviour of a mixed binder carbon paste electrode system appropriate for the cathodic stripping voltammetric quantitation of iso-niazid. The mixed binder consisted of glycerol a...This paper covers the construction and behaviour of a mixed binder carbon paste electrode system appropriate for the cathodic stripping voltammetric quantitation of iso-niazid. The mixed binder consisted of glycerol and liquid paraffin. At the mixed binder carbon paste electrodes in a pH 3.0 buffer solution, isoniazid showed two sensitive cathodic stripping voltammetric wave at-0. 75 V (p1) and-0. 88 V (p2) , respectively. The p2 can be used for the determination of trace amounts of isoniazid, the linear range of the peak current to the isoniazid concentration being from 5. 0×10-7 to 5.0×10-5 mol/L, and the limit of detection being 1. 0×10-7 mol/L with a relative standard deviation of 6. 0%(n=10). The proposed method was directly used to determine the drug in blood serum without the pretreatment of blood serum.展开更多
A novel sensitive electrochemical immunoassay with colloidal gold as the antibody labeling tag and subsequent signal amplification by silver enhancement is described. Colloidal gold was treated by a light-sensitive si...A novel sensitive electrochemical immunoassay with colloidal gold as the antibody labeling tag and subsequent signal amplification by silver enhancement is described. Colloidal gold was treated by a light-sensitive silver enhancement system which made silver deposit on the surface of colloidal gold(form Au/Ag core-shell structure), followed by the release of the metallic silver atoms anchored on the antibody by oxidative dissolution of them in an acidic solution and the indirect determination of the dissolved Ag + ions by anodic stripping voltammetry(ASV) at a carbon fiber microelectrode. The electrochemical signal is directly proportional to the amount of analyte(goat IgG) in the standard or a sample. The method was evaluated by means of a noncompetitive heterogeneous immunoassay of immunoglobulin G(IgG) with a concentration as low as 0.2 ng/mL. The high performance of the method is related to the sensitive ASV determination of silver(Ⅰ) at a carbon fiber microelectrode and to the release of a large number of Ag + ions from each silver shell anchored on the analyte(goat IgG).展开更多
The cyclic voltammetry(CV) and the square wave technique were used for the investigations of thallium(Ⅰ) underpotential deposition(UPD) on the silver electrode. A solution of 10 \{mmol/L\} HClO 4+10 mmol/L NaCl was s...The cyclic voltammetry(CV) and the square wave technique were used for the investigations of thallium(Ⅰ) underpotential deposition(UPD) on the silver electrode. A solution of 10 \{mmol/L\} HClO 4+10 mmol/L NaCl was selected as the supporting electrolyte. The calibration plots for Tl(Ⅰ) concentration in the range of 2×10 -9 -1×10 -7 mol/L were obtained. The detection limit was 5×10 -10 mol/L. For the solutions of 4 0×10 -9 mol/L thallium added before the urine sample pretreatment procedure, the average recovery was 105 6% with a relative standard deviation(RSD) of 15 5%.展开更多
Nanomolar levels of the hypoxanthine in NaOH electrolyte cantaining copper(Ⅱ) can be determined by anodic stripping voltammetry at a glassy carbon electrode. In the present article hypoxanthine Cu + is shown to be ...Nanomolar levels of the hypoxanthine in NaOH electrolyte cantaining copper(Ⅱ) can be determined by anodic stripping voltammetry at a glassy carbon electrode. In the present article hypoxanthine Cu + is shown to be adsorbed on the electrode surface in the presence of an excess of copper(Ⅱ). After accumulation period, hypoxanthine Cu + was stripped from the electrode surface and the anodic current coming near to the oxidation of Cu(Ⅰ) to Cu(Ⅱ) was measured. A linear calibration curve in the range of 5 nmol/L 1.5 mmol/L hypoxanthine, with a detection limit of 0.5 nmol/L hypoxanthine were obtained.展开更多
An electrochemical method for the simultaneous determination of lead(II) and Cadmium(II) with a calix[6]arene modified carbon paste electrode (CPE) has been developed. Pb2+ and Cd2+ were accumulated at the surface of ...An electrochemical method for the simultaneous determination of lead(II) and Cadmium(II) with a calix[6]arene modified carbon paste electrode (CPE) has been developed. Pb2+ and Cd2+ were accumulated at the surface of the modified electrode via formation of chemical complexes with calix[6]arene, and reduced at 1.40 V. During the following anodic potential sweep, reduced lead and cadmium were oxidized, and two well-defined striping peaks appeared at about ?0.60 V and ?0.84 V. Compared with a bare carbon paste electrode, the calix[6]arene modified CPE greatly improves the sensitivity of determining lead and cadmium. The stripping peak currents change linearly with the concentration of Pb2+ 3.0×10?8–8.0×10?6 mol·L?1 and with that of Cd2+ 6.0×10?8–1.0×10?5 mol ·L?1. The detection limits of Pb2+ and Cd2+ are found to be 8.0×10?9 mol·L?1 and 2.0×10?8 mol·L?1, respectively. The modified carbon paste electrode was applied to determine trace levels of lead and cadmium in water samples. Comparing with that of atomic absorption spectrometry, the results suggests that the calix[6]arene modified CPE has great potential for the practical sample analysis. Key words lead(II) - cadmium(II) - calix[6]arene - differential pulse stripping voltammetry - chemically modified electrode CLC number O 657.15 Foundation item: Supported by the National Natural Science Foundation of China (60171023)Biography: JI Xiao-bo (1980-), male, Master, research direction: electroanalytical chemistry.展开更多
In this paper, the electrochendcal behavior of bavistin (MBC) on glassy carbon electrode is reported. In a base solution of pH=9.0 NH3-NH4Cl, a sensitive anodic peak was found by cyclic voltammetry. Differential pulse...In this paper, the electrochendcal behavior of bavistin (MBC) on glassy carbon electrode is reported. In a base solution of pH=9.0 NH3-NH4Cl, a sensitive anodic peak was found by cyclic voltammetry. Differential pulse stripping voltanunetry was applied for determing MBC in grains. The detection limit is 4×10-8mo/L.The recovery is from 91.3% to 95.7%. The method has advantages of simplicity and high sensitivity.展开更多
基金the National Natural Science Foundation of China (No. 20365002, 20562009) the Natural Science of Jiangxi Province Foundation (No. 0320014) the foundation of the State Key Laboratories of Electroanalytical Chemistry of Changchun Applied Chemical Institute (No. SKLEAC2004-3) wen gratefully acknowledged.
文摘The adsorptive and electrochemical behaviour of phoxim on a hanging mercury drop electrode were explored in NH3·H2O-NH4Cl buffer by using cyclic and linear sweep voltmmetry. The procedure was successfully applied for the assay of phoxim in vegetable and fruit samples.
基金Supported by the National Natural Science Foundation of China(Nos. 20365002 and 20562009), the State Key Laboratory ofElectroanalytical Chemistry of Changchun Applied Chemistry Institute(No. 2004-3) and State Key Laboratory Chemo/Biosensing andChemometrics of Hunan University(No. 2005-22), the Jiangxi Provincial Natural Science Foundation(No. 0620041), and the Pro-gram for Changjiang Scholars and Innovative Research Team in Universities(No. 0540)
文摘The presence of the pesticide ethion was determined using an electroanalytical method, i. e. , linear sweep stripping voltammetry at a hanging mercury drop electrode in the Britton-Robbinson buffer with pH = 8. 36, based on its reduction peak observed at - 690 mV following its alkaline hydrolysis. The experimental parameters, namely, the preconcentration potential, the preconcentration time, and the scan rate were investigated and - 300 mV (vs. Ag/ AgCl), 270 s, and 100 mV/s were selected as the optimal values, respectively. The linear relationship between the peak current and the concentration was found to be in the range of 0.02-0. 16 mg/L, with a detection limit of 0.0087 mg/L. The proposed method was applied to the determination of ethion in spiked vegetable and fruit samples via a preextraction with anhydrous ethanol.
基金Supported by the National Natural Science Foundation of China(No.2 0 0 6 5 0 0 1) the Jiangxi Province Natural ScienceFoundation(No.0 0 2 0 0 2 2 ) and the State Key L aboratory of Chemo/ Biosensing and Chemometrics of Hunan U niversity.
文摘This paper reports the electrochemical properties of sulpiride at a mercury electrode, especially its adsorptive characteristic. Sulpiride dissolved in a supporting electrolyte of a McIlvaine buffer at pH 6 8 represents a sensitive and well defined reduction wave by linear sweep stripping voltammetry. This method is based on the pre concentration and the reduction of sulpiride at a hung mercury drop electrode. The reduction peak potential is -1 72 V( vs . Ag AgCl) and the peak current is proportional to the concentration of sulpiride in the range of 0 1-0 6 μg/mL. The detection limit is 0 025 μg/mL obtained under the experimental conditions selected in this work. The electrochemical properties of this system were investigated, and the proposed method was applied to the determination of sulpiride in pharmaceutical tablets with satisfactory results. It was compared well with the UV spectrophotometric method, showing a superior sensitivity.
基金funded by the Deanship of Scientific Research (DSR),King Abdulaziz University under grant number 172/428
文摘The redox behavior of spironolactone(SP) drug in Britton-Robinson(BR) buffer of pH 2-11 was investigated by differential pulse cathodic stripping voltammetry(DPCSV) and cyclic voltammetry(CV) at hanging mercury dropping electrode(HMDE).At pH 9-10.5,the DPCSV of SP drug showed two cathodic peaks at1.15 and1.38 V at the HMDE vs.Ag/AgCl reference electrode.In the CV,at pH 9-10,the dependence of the cathodic peak current,Ip,c and peak potential,Ep,c of the second peak(Ep,c2) on the scan rate(n) and on the depolizer(SP) concentrations was typical of an electrode coupled(EC) chemical reaction type mechanism.The plot of Ip,cat 1.380 V of the DPCSV vs.SP concentration at pH 9 was linear over the concentration range of 1.2×1010-9.6×107 M.The lower limit of detection(LLOD) and limit of quantification(LOQ) of the drug were 1.1×1011 and 4.14×1011 M,respectively.The method was successfully applied for the analysis of SP residues in industrial wastewater,in pure form(98.273.1%) and in drug formulations e.g.Aldactones tablet(98.3572.9%).The method was validated by comparison with HPLC and the official data methods.
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support by the National Natural Science Foundation of China (No21065007)the State Key Laboratory of Food Science and Technology of Nanchang University(SKLF-MB-201002 and SKLF-TS-200919)
文摘A reliable method for simultaneous determination of three antibiotic drugs(levofloxacin,gatifloxacin and lomefloxacin) by differential pulse stripping voltammetry(DPSV) in Britton-Robinson buffer(pH 7.96) was presented.The method is based on adsorptive accumulation of the antibacterial drugs on a hanging mercury dropping electrode(HMDE),followed by the reduction of the adsorptive species by the technique of DPSV.Optimal conditions,the deposition time of 80 s,the deposition potential of—1250 mV,and the scan rate of 25 mV/s,were obtained.The linear concentration ranges of 0.010-0.080μg/mL were obtained for all these three antibiotic drugs,while the detection limits were 2.38,3.20 and 1.60ng/mL for levofloxacin,gatifloxacin and lomefloxacin,respectively.In this work,chemometrics methods,such as classical least squares(CLS),partial least squares(PLS), principle component regression(PCR) and radial basis function-artificial neural networks(RBF-ANN),were used to quantitatively resolve the overlapping signals.It was found that PCR gave the best results with total relative prediction error(RPE_T) of 7.71%.The proposed method was applied to determine these three drugs in several commercial food samples with spiked method and yielded satisfactory recoveries.
基金financially supported by the marine high-tech industry development projects of Fujian Province(No.2015-19)
文摘An electrochemical flow device has been developed for the determination of heavy metal ions(HMI)in water using multiwalled carbon nanotubes(MWCNTs)/Nafion(NA)/Hg electrode,by mean of diff erential pulse anodic stripping voltammetry coupled with sequential injection analysis.The accuracy of the determination was ensured by the great electrical conductivity of MWCNTs and the high adsorption capacity of Hg.NA was used for MWCNTs immobilization for the long-term application of the electrode.The mercury film was cleaned after determination and another one would form during deposition.A lower limit of detection and a wider determination range of Cd^(2+)and Pb^(2+)could be achieved using the automatically analytical device combining with the MWCNTs/NA/Hg-modified electrode.The real-time monitoring of Cd^(2+)and Pb^(2+)in fresh water using this device continued for 10 days.The results indicated that the method was potential for on-site and real-time determination of HMI in water samples.
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.
文摘Poly(neutral red) film modified carbon fibre microelectrodes offer substantial improvement in voltammetric sensitivity and selectivity towards epinephrine (EP). The poly(neutral red) film was electropolymerized by cycling the potential between -0.8 V and +0.8 V. The anodic stripping voltammetric response for EP was found to be dependent on accumulation time and potential. By using a poly(neutral red) film modified carbon fibre microelectrode with a 1 min preconcentration at -1.2 V in biological phosphate buffer solution (pH=7.4), a good linear relationship between the anodic stripping peak currents and EP concentrations was obtained in the range of 2.0×10 -7  ̄ 2.0×10 -5 mol/L. The detection limit was up to 9.0 ×10 -8 mol/L. Moreover, 400 times higher concentrations of vitamin C did not interfere with the measurement of EP. This method was used for determining EP concentrations in epinephrine hydrochloride injection solution with satisfactory results.
文摘he present paper covers the construction and behaviour of a mixed binder car-bon paste electrode modified by surfactant system appropriate for the anodic strip-ping voltammetric quantitation of sulphadiazine. The mixed binder consisted ofglycerol and liquid paraffin. On this electrode in a PH 8. 20 buffer solution sulpha-diazine yields a sensitive anodic stripping voltammetric wave at 0. 82 V. It can beused for the determination of trace amounts of drug, the linear range of the peakcurrent to the sulphadiazine concentration being from 1. 0 x 10-7 to 5. 0 x 10-5mol/L, and the detection limit being 6. 6 x 10-9 mol/L with a relative standard de-viation of 2. 6% (n= 15).The proposed method was used to determine the drug inurine samples.
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Supported by the National Natural Science Foundation of China(No. 20562009)the Natural Science Foundation of Jiangxi Province, China(No. 0620041)+1 种基金the State Key Laboratory of the Chemo/Biosensing and Chemometrics of Hunan University, Chi-na(No. 2005-22)the Program for Changjiang Scholars and Innovative Research Team in Universities of China(No. IRT0540).
文摘Differential pulse stripping voltammetry method(DPSV) was applied to the determination of three herbicides, ametryn, cyanatryn, and dimethametryn. It was found that their voltammograms overlapped strongly, and it is difficult to determine these compounds individually from their mixtures. With the aid of chemometrics, classical least squares(CLS), principal component regression(PCR) and partial least squares(PLS), voltammogram resolution and quantitative analysis of the synthetic mixtures of the three compounds were successfully performed. The proposed method was also applied to the analysis of some real samples with satisfactory results.
基金Supported by the Nature Science Fund Project of Hubei Province
文摘A chitosan modified glassy carbon electrode(CMGCE) was employed for the determination of thiocyanate. The measurement was carried out by means of anodic stripping voltammetry. The effects of several experimental parameters, such as pH, the amount of modifier, deposition potential and deposition time were studied for analytical application, respectively. A liner response was obtained in the concentration range of 3 5×10 -8 - 9.3×10 -7 g/mL of SCN -. The detection limit was found to be 1.9×10 -8 g/mL. The method was satisfactorily used to detect SCN - in saliva.
基金the National Natural Science Foundation of China(Nos.20405008,20635020).
文摘An electrochemical method for the simultaneous detection of two different DNA sequences from PAT and FMV 35S gene sequence using CdS and PbS quantum dots (QDs) as labels was described. The QDs were readily functionalized with oligonucleotides as electrochemical DNA probes and selectively hybridized to the complementary sequences immobilized on the microplate. The QDs anchored on the hybrids were dissolved in the solution by the oxidation of HNO3 and further detected by a sensitive differential pulse anodic stripping voltammetric method (DPASV). The DPASV signals of the oxidation of Cd^2+ and Pb^2+ ions present in the solution were different and reflected the identity of corresponding ssDNA targets sequences.
文摘This paper covers the construction and behaviour of a mixed binder carbon paste electrode system appropriate for the cathodic stripping voltammetric quantitation of iso-niazid. The mixed binder consisted of glycerol and liquid paraffin. At the mixed binder carbon paste electrodes in a pH 3.0 buffer solution, isoniazid showed two sensitive cathodic stripping voltammetric wave at-0. 75 V (p1) and-0. 88 V (p2) , respectively. The p2 can be used for the determination of trace amounts of isoniazid, the linear range of the peak current to the isoniazid concentration being from 5. 0×10-7 to 5.0×10-5 mol/L, and the limit of detection being 1. 0×10-7 mol/L with a relative standard deviation of 6. 0%(n=10). The proposed method was directly used to determine the drug in blood serum without the pretreatment of blood serum.
基金Supportted by the National Natural Science Foundation of China( No.2 0 0 730 16 ,6 0 2 710 2 0 ),86 3projects( No.2 0 0 2 AA302203)and973projects( No.G19990 6 4 5 0 4 )
文摘A novel sensitive electrochemical immunoassay with colloidal gold as the antibody labeling tag and subsequent signal amplification by silver enhancement is described. Colloidal gold was treated by a light-sensitive silver enhancement system which made silver deposit on the surface of colloidal gold(form Au/Ag core-shell structure), followed by the release of the metallic silver atoms anchored on the antibody by oxidative dissolution of them in an acidic solution and the indirect determination of the dissolved Ag + ions by anodic stripping voltammetry(ASV) at a carbon fiber microelectrode. The electrochemical signal is directly proportional to the amount of analyte(goat IgG) in the standard or a sample. The method was evaluated by means of a noncompetitive heterogeneous immunoassay of immunoglobulin G(IgG) with a concentration as low as 0.2 ng/mL. The high performance of the method is related to the sensitive ASV determination of silver(Ⅰ) at a carbon fiber microelectrode and to the release of a large number of Ag + ions from each silver shell anchored on the analyte(goat IgG).
文摘The cyclic voltammetry(CV) and the square wave technique were used for the investigations of thallium(Ⅰ) underpotential deposition(UPD) on the silver electrode. A solution of 10 \{mmol/L\} HClO 4+10 mmol/L NaCl was selected as the supporting electrolyte. The calibration plots for Tl(Ⅰ) concentration in the range of 2×10 -9 -1×10 -7 mol/L were obtained. The detection limit was 5×10 -10 mol/L. For the solutions of 4 0×10 -9 mol/L thallium added before the urine sample pretreatment procedure, the average recovery was 105 6% with a relative standard deviation(RSD) of 15 5%.
文摘Nanomolar levels of the hypoxanthine in NaOH electrolyte cantaining copper(Ⅱ) can be determined by anodic stripping voltammetry at a glassy carbon electrode. In the present article hypoxanthine Cu + is shown to be adsorbed on the electrode surface in the presence of an excess of copper(Ⅱ). After accumulation period, hypoxanthine Cu + was stripped from the electrode surface and the anodic current coming near to the oxidation of Cu(Ⅰ) to Cu(Ⅱ) was measured. A linear calibration curve in the range of 5 nmol/L 1.5 mmol/L hypoxanthine, with a detection limit of 0.5 nmol/L hypoxanthine were obtained.
文摘An electrochemical method for the simultaneous determination of lead(II) and Cadmium(II) with a calix[6]arene modified carbon paste electrode (CPE) has been developed. Pb2+ and Cd2+ were accumulated at the surface of the modified electrode via formation of chemical complexes with calix[6]arene, and reduced at 1.40 V. During the following anodic potential sweep, reduced lead and cadmium were oxidized, and two well-defined striping peaks appeared at about ?0.60 V and ?0.84 V. Compared with a bare carbon paste electrode, the calix[6]arene modified CPE greatly improves the sensitivity of determining lead and cadmium. The stripping peak currents change linearly with the concentration of Pb2+ 3.0×10?8–8.0×10?6 mol·L?1 and with that of Cd2+ 6.0×10?8–1.0×10?5 mol ·L?1. The detection limits of Pb2+ and Cd2+ are found to be 8.0×10?9 mol·L?1 and 2.0×10?8 mol·L?1, respectively. The modified carbon paste electrode was applied to determine trace levels of lead and cadmium in water samples. Comparing with that of atomic absorption spectrometry, the results suggests that the calix[6]arene modified CPE has great potential for the practical sample analysis. Key words lead(II) - cadmium(II) - calix[6]arene - differential pulse stripping voltammetry - chemically modified electrode CLC number O 657.15 Foundation item: Supported by the National Natural Science Foundation of China (60171023)Biography: JI Xiao-bo (1980-), male, Master, research direction: electroanalytical chemistry.
文摘In this paper, the electrochendcal behavior of bavistin (MBC) on glassy carbon electrode is reported. In a base solution of pH=9.0 NH3-NH4Cl, a sensitive anodic peak was found by cyclic voltammetry. Differential pulse stripping voltanunetry was applied for determing MBC in grains. The detection limit is 4×10-8mo/L.The recovery is from 91.3% to 95.7%. The method has advantages of simplicity and high sensitivity.