Adsorptive enhancements of several water-soluble polymers on copper(Ⅱ) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode. Increases in peak current of cu(Ⅱ) were observed in al...Adsorptive enhancements of several water-soluble polymers on copper(Ⅱ) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode. Increases in peak current of cu(Ⅱ) were observed in alkaline carbonate media. The enhancing power of poly(vinyl alcohol), starch and polyallylamine is 15, 4. 1, and 2.5 times, repectively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
A quasi-reversible reduction peak of a fentanyl derivative DNPME is found by cyclic voltammetry at Hg electrode. E_(pc)=-1.58 V (vs. Ag/AgCl). The cathodic peak shows adsorptive characteristics. The adsorbed species i...A quasi-reversible reduction peak of a fentanyl derivative DNPME is found by cyclic voltammetry at Hg electrode. E_(pc)=-1.58 V (vs. Ag/AgCl). The cathodic peak shows adsorptive characteristics. The adsorbed species is DNPME neutral molecule. The method for measuring trace amount of DNPME by adsorptive stripping voltammetry is established.展开更多
Cyclic voltammetry shows that DBPPH has a pair of cathodic and anodic peaks at Hg electrode.Epc=-1.49 V and Fpa=-1.43 V(vs.Ag/AgCl).The cathodic peak shows adsorptive characteristics.The adsorbed species is DBPPH neut...Cyclic voltammetry shows that DBPPH has a pair of cathodic and anodic peaks at Hg electrode.Epc=-1.49 V and Fpa=-1.43 V(vs.Ag/AgCl).The cathodic peak shows adsorptive characteristics.The adsorbed species is DBPPH neutral molecule. The method for measuring trace amount of DBPPH by adsorptive stripping voltammetry is established.展开更多
Ultra trace determination of lantanum（Ⅲ） has been studied by adsorptive stripping voltammetry methods using an alizarin S as complexing agent and carbon paste electrode as working electrode. The electrode was made ...Ultra trace determination of lantanum（Ⅲ） has been studied by adsorptive stripping voltammetry methods using an alizarin S as complexing agent and carbon paste electrode as working electrode. The electrode was made from mixed of carbon powder and paraffin in micropipette tip with diameter of 4 ram. This method consists of two steps. The first step is the formation and adsorptive accumulation of metal ion with chelator at the electrode surface. The second step is stripping the complex from the electrode surface into the solution. The stripping step generates current which is recorded as voltammogram. The optimum conditions of instrumental parameter obtained were accumulation potential of 600 mV, accumulation time of 120 seconds, and pH of solution of 5.5. In this research, the limit detection obtained was 2.3348 × 10^-12 M （3.24× 10^-11μg/L） with sensitivity of 16.52 （nA/10u M） and the precision of standard solution of La3＋ with concentration of 2 × 10^-12 M, 4× 10^-12 M, 6 × 10^-12 M, 8 × 10^-12 M, and 10 × 10^-12M were 3.50%, 9.88%, 7.19%, 7.48% and 1.85% respectively. The linierity of this method is very good with correlation coefficient is 0.9780. Recovery percentage from La3＋ with concentration of 6× 10^-12 M and 10 × 10^-12 M are 108.84% and 91.51%, respectively.展开更多
Adsorptive enhancements of several inorganic salts on copper(II) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode Increase in peak curren of cu(II) were observed in alkaline phosp...Adsorptive enhancements of several inorganic salts on copper(II) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode Increase in peak curren of cu(II) were observed in alkaline phosphate or media owing to adsorption Silicate can also enhance the peak current of Cu(II). The enhancing power phosphate,carbonate, and silicate is 33, 26, and 8.9 times, respectively.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
In situ separation of ethanol during batch fermentation with CO_2 stripping and activated carbon adsorption was studied. The higher initial glucose concentration and fermentation rate were reached due to the eliminati...In situ separation of ethanol during batch fermentation with CO_2 stripping and activated carbon adsorption was studied. The higher initial glucose concentration and fermentation rate were reached due to the elimination of ethanol inhibition on the cell growth by means of CO_2 stripping. The stripped ethanol vapor was selectively adsorbed by an activated carbon column. The conde(?)sate desorbed from the adsorption column can be higher than 50% by weight. Ar unstructured model was used to simulate the experimental data satisfactorily.展开更多
A rapid and sensitive 1.5 order adsorptive stripping voltammetric method fordetendnation of trace mitoxantrone (MXT) is described. The accumulation behavior of MXT on amercury film ndcroelectrode was studied and the p...A rapid and sensitive 1.5 order adsorptive stripping voltammetric method fordetendnation of trace mitoxantrone (MXT) is described. The accumulation behavior of MXT on amercury film ndcroelectrode was studied and the possibility of carrying out 1.5 order differentialadsorptive stripping analysis using mercury-coated carbon fiber ndcroelectrode was demonstrated.Optimal conditions for 1.5 order differential voltammetry monitoring are described. The strippingpeak current is linearly proportional to the concentration of MAT in the range of 1.0×10-6 mol/L 1.0×10-9 and detection licit is 1.5×10-10 mol/L. The relative standard deviation (RSD) is 3.0% at5.0×10-8 (n=8). MXT can be detendned directly in biological samples at physiological levelswithout any separation procedure.展开更多
Active carbons(ACs) were prepared through chemical activation of biochar from whole corn stalk(WCS)and corn stalk pith(CSP) at varying temperatures using potassium hydroxide as the activating agent. ACs were character...Active carbons(ACs) were prepared through chemical activation of biochar from whole corn stalk(WCS)and corn stalk pith(CSP) at varying temperatures using potassium hydroxide as the activating agent. ACs were characterized via pore structural analysis and scanning electron microscopy(SEM). These adsorbents were then assessed for their adsorption capacity for butanol vapor. It was found that WCS activated at900 °C for 1 h(WCS-900) had optimal butanol adsorption characteristics. The BET surface area and total pore volume of the WCS-900 were 2330 m2/g and 1.29 cm3/g, respectively. The dynamic adsorption capacity of butanol vapor was 410.0 mg/g, a 185.1% increase compared to charcoal-based commercial AC(143.8 mg/g).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Adsorptive enhancements of several water-soluble polymers on copper(Ⅱ) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode. Increases in peak current of cu(Ⅱ) were observed in alkaline carbonate media. The enhancing power of poly(vinyl alcohol), starch and polyallylamine is 15, 4. 1, and 2.5 times, repectively
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This work was supported by the National Natural Science Foundation of China
文摘A quasi-reversible reduction peak of a fentanyl derivative DNPME is found by cyclic voltammetry at Hg electrode. E_(pc)=-1.58 V (vs. Ag/AgCl). The cathodic peak shows adsorptive characteristics. The adsorbed species is DNPME neutral molecule. The method for measuring trace amount of DNPME by adsorptive stripping voltammetry is established.
文摘Cyclic voltammetry shows that DBPPH has a pair of cathodic and anodic peaks at Hg electrode.Epc=-1.49 V and Fpa=-1.43 V(vs.Ag/AgCl).The cathodic peak shows adsorptive characteristics.The adsorbed species is DBPPH neutral molecule. The method for measuring trace amount of DBPPH by adsorptive stripping voltammetry is established.
文摘Ultra trace determination of lantanum（Ⅲ） has been studied by adsorptive stripping voltammetry methods using an alizarin S as complexing agent and carbon paste electrode as working electrode. The electrode was made from mixed of carbon powder and paraffin in micropipette tip with diameter of 4 ram. This method consists of two steps. The first step is the formation and adsorptive accumulation of metal ion with chelator at the electrode surface. The second step is stripping the complex from the electrode surface into the solution. The stripping step generates current which is recorded as voltammogram. The optimum conditions of instrumental parameter obtained were accumulation potential of 600 mV, accumulation time of 120 seconds, and pH of solution of 5.5. In this research, the limit detection obtained was 2.3348 × 10^-12 M （3.24× 10^-11μg/L） with sensitivity of 16.52 （nA/10u M） and the precision of standard solution of La3＋ with concentration of 2 × 10^-12 M, 4× 10^-12 M, 6 × 10^-12 M, 8 × 10^-12 M, and 10 × 10^-12M were 3.50%, 9.88%, 7.19%, 7.48% and 1.85% respectively. The linierity of this method is very good with correlation coefficient is 0.9780. Recovery percentage from La3＋ with concentration of 6× 10^-12 M and 10 × 10^-12 M are 108.84% and 91.51%, respectively.
文摘Adsorptive enhancements of several inorganic salts on copper(II) were studied by adsorptive stripping voltammetry with a hanging mercury drop electrode Increase in peak curren of cu(II) were observed in alkaline phosphate or media owing to adsorption Silicate can also enhance the peak current of Cu(II). The enhancing power phosphate,carbonate, and silicate is 33, 26, and 8.9 times, respectively.
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.
文摘In situ separation of ethanol during batch fermentation with CO_2 stripping and activated carbon adsorption was studied. The higher initial glucose concentration and fermentation rate were reached due to the elimination of ethanol inhibition on the cell growth by means of CO_2 stripping. The stripped ethanol vapor was selectively adsorbed by an activated carbon column. The conde(?)sate desorbed from the adsorption column can be higher than 50% by weight. Ar unstructured model was used to simulate the experimental data satisfactorily.
文摘A rapid and sensitive 1.5 order adsorptive stripping voltammetric method fordetendnation of trace mitoxantrone (MXT) is described. The accumulation behavior of MXT on amercury film ndcroelectrode was studied and the possibility of carrying out 1.5 order differentialadsorptive stripping analysis using mercury-coated carbon fiber ndcroelectrode was demonstrated.Optimal conditions for 1.5 order differential voltammetry monitoring are described. The strippingpeak current is linearly proportional to the concentration of MAT in the range of 1.0×10-6 mol/L 1.0×10-9 and detection licit is 1.5×10-10 mol/L. The relative standard deviation (RSD) is 3.0% at5.0×10-8 (n=8). MXT can be detendned directly in biological samples at physiological levelswithout any separation procedure.
基金supported by following projects:“Development of high value carbon based adsorbents from thermochemically produced biochar”USDA-NIFA2011-67009-20030 through the USDA-NIFA Agriculture and Food Research Initiative Sustainable Bioenergy Program which funded the Micropore analyzer and instruments for modifying AC+1 种基金NSF EPSCoR TrackⅡDakota Bio Con center(National Science Foundation/EPSCo R Award No.1330842)supported Mr.Cao Yuhe for his PhD study and GC–MS instrumentDOE Sun Grant Concept Project“Developing Gas Stripping-Adsorption/Desorption Separation Processes based on Porous Carbon Adsorbents for Biofuel Purification from Bioreactors”(North Central Sun Grant Award No.1300478)supported upgrading the Chemical Adsorption Analyzer
文摘Active carbons(ACs) were prepared through chemical activation of biochar from whole corn stalk(WCS)and corn stalk pith(CSP) at varying temperatures using potassium hydroxide as the activating agent. ACs were characterized via pore structural analysis and scanning electron microscopy(SEM). These adsorbents were then assessed for their adsorption capacity for butanol vapor. It was found that WCS activated at900 °C for 1 h(WCS-900) had optimal butanol adsorption characteristics. The BET surface area and total pore volume of the WCS-900 were 2330 m2/g and 1.29 cm3/g, respectively. The dynamic adsorption capacity of butanol vapor was 410.0 mg/g, a 185.1% increase compared to charcoal-based commercial AC(143.8 mg/g).
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.
