A simple and rapid approach for the electrochemical synthesis of Ag nanoparticles-coated gold nanoporous film (AgGNF) on a gold substrate was reported. The solid gold electrode (SGE) was directly anodized under a high...A simple and rapid approach for the electrochemical synthesis of Ag nanoparticles-coated gold nanoporous film (AgGNF) on a gold substrate was reported. The solid gold electrode (SGE) was directly anodized under a high potential of 5 V, and then reduced to obtain gold nanoporous film (AuNF) by freshly prepared ascorbic acid. The Ag nanoparticles (AgNPs) were grown on the AuNF electrode by potential-step electrodeposition. The resulting AgGNF composites electrodes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and cyclic voltammetry (CV). As-prepared AgGNF electrode was used as a kind of superior sensor for Cr(VI) detection, which exhibited better electrocatalytic behavior than those of AuNF and SGE under identical conditions. Such a designed AgGNF nanocomposites electrode showed outstanding sensitivity (about 0.15 nA/ppb) and favorable reproducibility for Cr(VI) detection. The dependence of reduction current on Cr(VI) concentration is linear from 2 to 370 ppb with a low detection limit of 0.65 ppb. Interferences from other heavy metals ions (Cr3+, Cu2+, Pb2+, As3+ and Hg2+) associated with Cr(VI) analysis could be effectively diminished. The present method proves to be rapid, reliable, sensitive and low-cost.展开更多
A high-performance capillary electrophoresis with amperometry detection method （CE-AD） has been developed for the analysis of flavonoids and anthraquinones （emodin, kaempferol, apigenin, luteolin and rhein） in chr...A high-performance capillary electrophoresis with amperometry detection method （CE-AD） has been developed for the analysis of flavonoids and anthraquinones （emodin, kaempferol, apigenin, luteolin and rhein） in chrysanthemum. Under optimum conditions, these five analytes were base-line separated within 17 min using a borate-phosphate running buffer （1.5 ×10^-2 mol/L borate-3× 10^-2 mol/L phosphate running buffer, pH 9.0） at a working potential of ＋0.90 V （vs. SCE） and a separation voltage of 19 kV. The linear relationship between concentration and current response was obtained with detection limits （S/N = 3） ranging from 1.0 × 10^-7 to 2.1 × 10^-7 g/mL for all analytes. This proposed method was successfully used in the analysis of four kinds of chrysanthemum with relatively simple extraction procedures, the assay results were satisfactory.展开更多
The use of electrochemical sensors for sensitive disease diagnosis and detecting various species with pharmacological,therapeutic,industrial,food-related,and environmental origins is now widely accepted.A catalytic or...The use of electrochemical sensors for sensitive disease diagnosis and detecting various species with pharmacological,therapeutic,industrial,food-related,and environmental origins is now widely accepted.A catalytic or binding event resulting from the sensor’s electroactive component recognizing its analyte creates an electrical signal proportionate to the analyte concentration,which is then monitored by a transducer.The development of morphologically distinct metal and metal oxide nanoparticles formed from first-row transition elements(Mn,Cr,Fe,Co,Ti,Ni,Cu,Zn)and noble metals(Pt,Au,Ag,Pd)is described in this review.The effect of these metal nanoparticles has been studied using Tetracyanoquinodimethane(TCNQ),Ferrocene,and other organic compounds as electroactive species using carbon paste-modified electrodes.Electroanalytical sensors,mostly based on ferrocene,are exceedingly sensitive,selective,affordable,and for detecting numerous biomolecules like glucose,dopamine,NADH,ascorbic acid,and a few dyes and are simple to build.In recent decades,charge transfer organic species-based chemosensors have become a prominent study area.This paper outlines current developments in electrochemical biosensors based on transition metal nanoparticles,covering glucose,ascorbic acid,uric acid,and other inorganic and organic analytes.The importance of transition metal and transition metal oxide nanoparticles as potential electrode modifiers for developing sensors is highlighted.A discussion of the present problem and possible solutions,and plausible future directions marks the review’s conclusion.展开更多
Carbon fiber microelectrodes (CFEs) are useful when combined with electrochemical techniques for measuring changes in neurotransmitter concentrations. We addressed conflicting details regarding the use of CFEs. Experi...Carbon fiber microelectrodes (CFEs) are useful when combined with electrochemical techniques for measuring changes in neurotransmitter concentrations. We addressed conflicting details regarding the use of CFEs. Experimental groups consisted of CFEs at different ages (1 week, 1 month, or 2 months), cleaned in solvents (isopropanol or xylene), and exposed to in vitro use (flow cell calibrations) or in vivo use (in brain tissue). In order to determine if any of these factors affect CFE sensitivity, the present study utilized fixed potential amperometry and a flow injection system to calibrate CFEs for the measurement of dopamine. The sensitivity index (nA/μM per 100 μm of exposed carbon fiber) was not affected by the age of CFEs or pre-cleaning with xylene or isopropanol. CFE sensitivity of the in vitro exposure group also did not differ from untreated CFEs, indicating the calibration process did not alter sensitivity. However, in vivo use in brain tissue did reduce sensitivity. This effect was negated and sensitivity restored by cleaning CFEs in isopropanol or xylene following in vivo brain recordings. Given that variations in CFE sensitivity can skew results, our findings can help standardize CFE use and explain discrepancies between researchers.展开更多
hydrogen peroxide electrode with 1,1'-dimethylferrocene(DMFc)used as an electron transfer mediator has been described.Using Nafion, DMFc was modified on a glassy carbon electrode(GCE)surface,and horseradish peroxi...hydrogen peroxide electrode with 1,1'-dimethylferrocene(DMFc)used as an electron transfer mediator has been described.Using Nafion, DMFc was modified on a glassy carbon electrode(GCE)surface,and horseradish peroxidase(HRP)was then immobiliged on the DMFc-Nafion film,forming a HRp-DMFc-Nafion modi- fied electrode. The chracteristics of the sensor has been shown by cyclic voltam- metry and constant potential measurements,The sensor responds fastly to hydro- gen peroxide,the time required to reach 95%of the steady-state current is less than 50s. The sensor displays a sensitive catalytic current response to hydrogen peroxide and can be operated at a potential range in which the oxidation of common interfering species,such as ascorbic acid and uric acid,does not occur. The sensor is stable for 20 days and its detection limit is 1 μmol/L.展开更多
基金supported by the National Natural Science Foundation of China (21005014)the Foundation of Donghua University (113-10-0044029)
文摘A simple and rapid approach for the electrochemical synthesis of Ag nanoparticles-coated gold nanoporous film (AgGNF) on a gold substrate was reported. The solid gold electrode (SGE) was directly anodized under a high potential of 5 V, and then reduced to obtain gold nanoporous film (AuNF) by freshly prepared ascorbic acid. The Ag nanoparticles (AgNPs) were grown on the AuNF electrode by potential-step electrodeposition. The resulting AgGNF composites electrodes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and cyclic voltammetry (CV). As-prepared AgGNF electrode was used as a kind of superior sensor for Cr(VI) detection, which exhibited better electrocatalytic behavior than those of AuNF and SGE under identical conditions. Such a designed AgGNF nanocomposites electrode showed outstanding sensitivity (about 0.15 nA/ppb) and favorable reproducibility for Cr(VI) detection. The dependence of reduction current on Cr(VI) concentration is linear from 2 to 370 ppb with a low detection limit of 0.65 ppb. Interferences from other heavy metals ions (Cr3+, Cu2+, Pb2+, As3+ and Hg2+) associated with Cr(VI) analysis could be effectively diminished. The present method proves to be rapid, reliable, sensitive and low-cost.
基金financially supported by The Program for New Century Excellent Talents in University
文摘A high-performance capillary electrophoresis with amperometry detection method （CE-AD） has been developed for the analysis of flavonoids and anthraquinones （emodin, kaempferol, apigenin, luteolin and rhein） in chrysanthemum. Under optimum conditions, these five analytes were base-line separated within 17 min using a borate-phosphate running buffer （1.5 ×10^-2 mol/L borate-3× 10^-2 mol/L phosphate running buffer, pH 9.0） at a working potential of ＋0.90 V （vs. SCE） and a separation voltage of 19 kV. The linear relationship between concentration and current response was obtained with detection limits （S/N = 3） ranging from 1.0 × 10^-7 to 2.1 × 10^-7 g/mL for all analytes. This proposed method was successfully used in the analysis of four kinds of chrysanthemum with relatively simple extraction procedures, the assay results were satisfactory.
文摘The use of electrochemical sensors for sensitive disease diagnosis and detecting various species with pharmacological,therapeutic,industrial,food-related,and environmental origins is now widely accepted.A catalytic or binding event resulting from the sensor’s electroactive component recognizing its analyte creates an electrical signal proportionate to the analyte concentration,which is then monitored by a transducer.The development of morphologically distinct metal and metal oxide nanoparticles formed from first-row transition elements(Mn,Cr,Fe,Co,Ti,Ni,Cu,Zn)and noble metals(Pt,Au,Ag,Pd)is described in this review.The effect of these metal nanoparticles has been studied using Tetracyanoquinodimethane(TCNQ),Ferrocene,and other organic compounds as electroactive species using carbon paste-modified electrodes.Electroanalytical sensors,mostly based on ferrocene,are exceedingly sensitive,selective,affordable,and for detecting numerous biomolecules like glucose,dopamine,NADH,ascorbic acid,and a few dyes and are simple to build.In recent decades,charge transfer organic species-based chemosensors have become a prominent study area.This paper outlines current developments in electrochemical biosensors based on transition metal nanoparticles,covering glucose,ascorbic acid,uric acid,and other inorganic and organic analytes.The importance of transition metal and transition metal oxide nanoparticles as potential electrode modifiers for developing sensors is highlighted.A discussion of the present problem and possible solutions,and plausible future directions marks the review’s conclusion.
文摘Carbon fiber microelectrodes (CFEs) are useful when combined with electrochemical techniques for measuring changes in neurotransmitter concentrations. We addressed conflicting details regarding the use of CFEs. Experimental groups consisted of CFEs at different ages (1 week, 1 month, or 2 months), cleaned in solvents (isopropanol or xylene), and exposed to in vitro use (flow cell calibrations) or in vivo use (in brain tissue). In order to determine if any of these factors affect CFE sensitivity, the present study utilized fixed potential amperometry and a flow injection system to calibrate CFEs for the measurement of dopamine. The sensitivity index (nA/μM per 100 μm of exposed carbon fiber) was not affected by the age of CFEs or pre-cleaning with xylene or isopropanol. CFE sensitivity of the in vitro exposure group also did not differ from untreated CFEs, indicating the calibration process did not alter sensitivity. However, in vivo use in brain tissue did reduce sensitivity. This effect was negated and sensitivity restored by cleaning CFEs in isopropanol or xylene following in vivo brain recordings. Given that variations in CFE sensitivity can skew results, our findings can help standardize CFE use and explain discrepancies between researchers.
文摘hydrogen peroxide electrode with 1,1'-dimethylferrocene(DMFc)used as an electron transfer mediator has been described.Using Nafion, DMFc was modified on a glassy carbon electrode(GCE)surface,and horseradish peroxidase(HRP)was then immobiliged on the DMFc-Nafion film,forming a HRp-DMFc-Nafion modi- fied electrode. The chracteristics of the sensor has been shown by cyclic voltam- metry and constant potential measurements,The sensor responds fastly to hydro- gen peroxide,the time required to reach 95%of the steady-state current is less than 50s. The sensor displays a sensitive catalytic current response to hydrogen peroxide and can be operated at a potential range in which the oxidation of common interfering species,such as ascorbic acid and uric acid,does not occur. The sensor is stable for 20 days and its detection limit is 1 μmol/L.
