A nonenzymatic electrochemical sensor for glucose and fructose was fabricated that contained a glassy carbon electrode modified with a copper oxide (CuO)/multiwalled carbon nanotube (MWCNT) nanocomposite. The electroc...A nonenzymatic electrochemical sensor for glucose and fructose was fabricated that contained a glassy carbon electrode modified with a copper oxide (CuO)/multiwalled carbon nanotube (MWCNT) nanocomposite. The electrochemical properties of the CuO/MWCNT‐modified glassy carbon electrode were investigated. Two distinguishable anodic peaks were observed around 0.30 and 0.44 V corresponding to the oxidation of glucose and fructose, respectively, at the surface of the modified electrode. The detection limits for glucose and fructose were both 0.04 mmol/L. The sensor was used to simultaneously determine the concentrations of glucose and fructose in hydrolyzed sucrose samples, and to measure glucose in blood serum samples, demonstrating its potential as a nonenzymatic carbohydrate sensor.展开更多
A carbon paste electrode with added multiwall carbon nanotubes chemically modified with N-(3,4-dihydroxyphenethyl)- 3,5-dinitrobenzamide was used as the electrochemical sensor for the determination of trace amounts of...A carbon paste electrode with added multiwall carbon nanotubes chemically modified with N-(3,4-dihydroxyphenethyl)- 3,5-dinitrobenzamide was used as the electrochemical sensor for the determination of trace amounts of isoprenaline. The modified electrode showed good electrocatalytic activity for the anodic oxidation of isoprenaline, which was due to a substantial decrease in the anodic overpotential. Under the optimum conditions, measurements using square wave voltammetry had a linear range in the range of 0.3 to 125.0 μmol/L of isoprenaline and a detection limit of 0.1 μmol/L. The diffusion coefficient and kinetic parameters were determined using electrochemical methods. The relative standard deviation for seven successive assays of 1.0 and 20.0 μmol/L isoprenaline were 1.9% and 2.4%, respectively.This electrochemical sensor was successfully applied for the determination of isoprenaline in human urine and injection solution samples.展开更多
Novel dopamine-derivative compound,3,5-diamino-N-（3,4-dihydroxyphenethyl）benzamide（3,5-DAB）was prepared in two steps.In the first step dopamine hydrochloride was reacted with 3,5-dinitrobenzoyl chloride in the pre...Novel dopamine-derivative compound,3,5-diamino-N-（3,4-dihydroxyphenethyl）benzamide（3,5-DAB）was prepared in two steps.In the first step dopamine hydrochloride was reacted with 3,5-dinitrobenzoyl chloride in the presence of propylene oxide.In the second step reduction of nitro groups resulted in preparation of 3,5-DAB in quantitative yield.This material was characterized using conventional spectroscopic methods such as FT-IR and ~1H NMR.In addition,the redox response of a modified carbon nanotubes paste electrode of 3,5-DAB was investigated in aqueous solution at a neutral pH.The result showed that the electrode process has a quasi-reversible response,withΔE_p,greater than the（59/n） mV expected for a reversible system.Finally,the diffusion coefficient for redox process in paraffin oil matrix obtained using chronoamperometry methods.展开更多
A carbon paste electrode（CPE） chemically modified with multiwall carbon nanotubes and ferrocene（FC） was used as a selective electrochemical sensor for the simultaneous determination of trace amounts of cysteamine...A carbon paste electrode（CPE） chemically modified with multiwall carbon nanotubes and ferrocene（FC） was used as a selective electrochemical sensor for the simultaneous determination of trace amounts of cysteamine（CA） and folic acid（FA）.This modified electrode showed very efficient electrocatalytic activity for the anodic oxidation of CA.The peak current of differential pulse voltammograms of CA and FA increased linearly with their concentration in the ranges of 0.7-200μmol/L CA and 5.0- 700μmol/L FA.The detection limits for CA and FA were 0.3μmol/L and 2.0μmoI/L,respectively.The diffusion coefficient（D） and transfer coefficient（α） of CA were also determined.These conditions are sufficient to allow determination of CA and FA both individually and simultaneously.展开更多
High-performance supercapacitors require electrodes featuring a high surface area,suitable porosity,and conductivity.Metal-organic frameworks(MOFs)hold a high surface area and suitable porosity while insufficient cond...High-performance supercapacitors require electrodes featuring a high surface area,suitable porosity,and conductivity.Metal-organic frameworks(MOFs)hold a high surface area and suitable porosity while insufficient conductivity.Herein,a single-step chemical strategy was developed to directly synthesize a composite of copper-nickel rubeanate MOF and highly conductive reduced graphene oxide(rGO)nanosheets(CNRG-MOF)on nickel foam(CNRG-MOF/NF)electrode.The nanocomposite enables it to use as a high-performance supercapacitor electrode.The bimetallic CNRG-MOF/NF electrode exhibits su-perior electrochemical performance than its single metallic counterparts.The optimized CNRG-MOF/NF electrode represents a high specific capacitance of 846.15 F g1 at a current density of 1.0 A g1.A three-electrode system exhibited up to 96.37%capacitance retention after 7000 galvanostatic charge-discharge(GCD)cycles,indicating its excellent stability.These results may pave the way for the direct use of MOF materials for electrochemical energy devices instead of pyrolyzing the MOFs to improve the conductivity while losing controllable structural merits.GCD curve was obtained at different current densities to evaluate the nanocomposite's asymmetric setup charge storage capability.The electrode capacity for the asymmetric system was measured as 93.3 F g1,which proves the capacitive property of CNRG-MOF/NF electrode.展开更多
基金The Iranian Nanotechnology Initiative,Research Council of Isfahan University of Technology,and Centre of Excellence in Sensor and Green Chemistry
文摘A nonenzymatic electrochemical sensor for glucose and fructose was fabricated that contained a glassy carbon electrode modified with a copper oxide (CuO)/multiwalled carbon nanotube (MWCNT) nanocomposite. The electrochemical properties of the CuO/MWCNT‐modified glassy carbon electrode were investigated. Two distinguishable anodic peaks were observed around 0.30 and 0.44 V corresponding to the oxidation of glucose and fructose, respectively, at the surface of the modified electrode. The detection limits for glucose and fructose were both 0.04 mmol/L. The sensor was used to simultaneously determine the concentrations of glucose and fructose in hydrolyzed sucrose samples, and to measure glucose in blood serum samples, demonstrating its potential as a nonenzymatic carbohydrate sensor.
基金supported by Isfahan University of Technology Research Council and the Center of Excellence for Sensor and Green Chemistry
文摘A carbon paste electrode with added multiwall carbon nanotubes chemically modified with N-(3,4-dihydroxyphenethyl)- 3,5-dinitrobenzamide was used as the electrochemical sensor for the determination of trace amounts of isoprenaline. The modified electrode showed good electrocatalytic activity for the anodic oxidation of isoprenaline, which was due to a substantial decrease in the anodic overpotential. Under the optimum conditions, measurements using square wave voltammetry had a linear range in the range of 0.3 to 125.0 μmol/L of isoprenaline and a detection limit of 0.1 μmol/L. The diffusion coefficient and kinetic parameters were determined using electrochemical methods. The relative standard deviation for seven successive assays of 1.0 and 20.0 μmol/L isoprenaline were 1.9% and 2.4%, respectively.This electrochemical sensor was successfully applied for the determination of isoprenaline in human urine and injection solution samples.
文摘Novel dopamine-derivative compound,3,5-diamino-N-（3,4-dihydroxyphenethyl）benzamide（3,5-DAB）was prepared in two steps.In the first step dopamine hydrochloride was reacted with 3,5-dinitrobenzoyl chloride in the presence of propylene oxide.In the second step reduction of nitro groups resulted in preparation of 3,5-DAB in quantitative yield.This material was characterized using conventional spectroscopic methods such as FT-IR and ~1H NMR.In addition,the redox response of a modified carbon nanotubes paste electrode of 3,5-DAB was investigated in aqueous solution at a neutral pH.The result showed that the electrode process has a quasi-reversible response,withΔE_p,greater than the（59/n） mV expected for a reversible system.Finally,the diffusion coefficient for redox process in paraffin oil matrix obtained using chronoamperometry methods.
文摘A carbon paste electrode（CPE） chemically modified with multiwall carbon nanotubes and ferrocene（FC） was used as a selective electrochemical sensor for the simultaneous determination of trace amounts of cysteamine（CA） and folic acid（FA）.This modified electrode showed very efficient electrocatalytic activity for the anodic oxidation of CA.The peak current of differential pulse voltammograms of CA and FA increased linearly with their concentration in the ranges of 0.7-200μmol/L CA and 5.0- 700μmol/L FA.The detection limits for CA and FA were 0.3μmol/L and 2.0μmoI/L,respectively.The diffusion coefficient（D） and transfer coefficient（α） of CA were also determined.These conditions are sufficient to allow determination of CA and FA both individually and simultaneously.
基金The authors wish to thank Iran National Science Foundation,grant No.98012523,for supporting this work.
文摘High-performance supercapacitors require electrodes featuring a high surface area,suitable porosity,and conductivity.Metal-organic frameworks(MOFs)hold a high surface area and suitable porosity while insufficient conductivity.Herein,a single-step chemical strategy was developed to directly synthesize a composite of copper-nickel rubeanate MOF and highly conductive reduced graphene oxide(rGO)nanosheets(CNRG-MOF)on nickel foam(CNRG-MOF/NF)electrode.The nanocomposite enables it to use as a high-performance supercapacitor electrode.The bimetallic CNRG-MOF/NF electrode exhibits su-perior electrochemical performance than its single metallic counterparts.The optimized CNRG-MOF/NF electrode represents a high specific capacitance of 846.15 F g1 at a current density of 1.0 A g1.A three-electrode system exhibited up to 96.37%capacitance retention after 7000 galvanostatic charge-discharge(GCD)cycles,indicating its excellent stability.These results may pave the way for the direct use of MOF materials for electrochemical energy devices instead of pyrolyzing the MOFs to improve the conductivity while losing controllable structural merits.GCD curve was obtained at different current densities to evaluate the nanocomposite's asymmetric setup charge storage capability.The electrode capacity for the asymmetric system was measured as 93.3 F g1,which proves the capacitive property of CNRG-MOF/NF electrode.
