A new capillary electrophoresis apparatus was designed. Piezoelectric ceramics transformer technology was first applied in capillary electrophoresis, a high voltage and stable source was made. Amperometric detector wa...A new capillary electrophoresis apparatus was designed. Piezoelectric ceramics transformer technology was first applied in capillary electrophoresis, a high voltage and stable source was made. Amperometric detector was used in which the working electrode was closely opposite to the end of capillary. The apparatus was characterized in good reproducibility, safety and very low cost.展开更多
A high-performance capillary electrophoresis with amperometric detection(CE-AD) method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic...A high-performance capillary electrophoresis with amperometric detection(CE-AD) method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum condit...展开更多
Response of biosensor prepared with the thermostable bacterial LDH enzyme was analyzed in the presence of mercury and nickel.For electrode preparation,the enzyme was purified and immobilized on a gold sheet coated by ...Response of biosensor prepared with the thermostable bacterial LDH enzyme was analyzed in the presence of mercury and nickel.For electrode preparation,the enzyme was purified and immobilized on a gold sheet coated by PGA-pyrrole polymeric material.The working electrode was tested at increasing concentration of lactate in the presence of two different concentrations of mercury and nickel.Current response of biosensor decreased from 0.32 μA to 0.09 μA and 4.13 μA to 2.63 μA when 25×10-7 mmol/L mercury and 17×10-5 mmol/L nickel were included in the working solution,respectively.Sensitivity of the electrode decreased from 0.010 2 μA/（mmol·L-1） to 0.0043 μA/（mmol·L-1） in the presence of 25×10-7 mmol/L mercury.On the other hand,the presence of nickel did not result in a decrease in electrode sensitivity.The results pointed out that the prepared biosensor is useful to detect mercury in a sample containing both mercury and nickel together.展开更多
A micro amperometric immunosensor with the sensitive area of only 1mm^2 was fabricated on silicon using the technique of Micro-Electro-Mechanical Systems (MEMS).A double exposure of SU-8 photoresist process was develo...A micro amperometric immunosensor with the sensitive area of only 1mm^2 was fabricated on silicon using the technique of Micro-Electro-Mechanical Systems (MEMS).A double exposure of SU-8 photoresist process was developed to create both the sensitive pool and reaction pool.Antibody was immobilized via cross-linking with glutaraldehyde on the sensitive area of the electrode surface,which was electropolymerized with polypyrrole previously.The immunosensor was characterized by detection of human immunoglobulin G (HIgG).The immunosensor displayed a good linear response to HIgG concentrations between 5ng/ml and 255ng/ml and demonstrated a fast response time of 3 minutes.展开更多
A circuit model of the Amperometric immunosensor for use in the biosensor system-on-chip simulation is proposed in this paper.The model parameters are extracted with several methods and verified by MATLAB and SPICE si...A circuit model of the Amperometric immunosensor for use in the biosensor system-on-chip simulation is proposed in this paper.The model parameters are extracted with several methods and verified by MATLAB and SPICE simulation.A CMOS potentiostat circuit required for conditioning the Amperometric immunosensor is also included in the circuit model.The mean square error norm of the simulated curve against the measured one is 8.65×10^(-17) The whole circuit has been fabricated in a 0.35μm CMOS process.展开更多
The present paper covers a simple, reliable and reproducible method, based on capillary zone electrophoresis(CZE) with amperometric detection(AD), for the separation and the determination of ephedrine hydrochloride, p...The present paper covers a simple, reliable and reproducible method, based on capillary zone electrophoresis(CZE) with amperometric detection(AD), for the separation and the determination of ephedrine hydrochloride, promethazine hydrochloride and codeine phosphate. Under the optimal conditions, the three analytes were base-line separated completely within 16 min. Good linear relationships between the peak heights and the concentrations of the three analytes were obtained with the correlation coefficients better than 0 9993. The method was directly applied to the determination of the active ingredients in pharmaceutical preparations and the assay results were satisfactory.展开更多
An amperometric glucose biosensor based on a tin oxide (SnO_2) electrode has been developed.The SnO_2 electrode is prepared by depositing the SnO_2 thin film onto a carbon electrode.To fabricate the SnO_2 amperometric...An amperometric glucose biosensor based on a tin oxide (SnO_2) electrode has been developed.The SnO_2 electrode is prepared by depositing the SnO_2 thin film onto a carbon electrode.To fabricate the SnO_2 amperometric glucose biosensor,the glucose oxidase and electron transfer mediator (ferrocenecarboxylic acid,FcA) are coimmobilized on the SnO_2 electrode using polyacrylamide.The detection range is up to glucose concentration of 520mg/dl as the applied potential is set at 300mV. Moreover,the most merit for the SnO_2 electrode as the base electrode of the SnO_2 amperometric glucose biosensor is that it can be operated at 150mV constant applied potential.The interference reduction,detection range,sensitivity and linearity are improved as the SnO_2 thin film is deposited onto a carbon electrode.Furthermore,due to the low cost substrate and simple fabrication characteristics,a disposable amperometric glucose biosensor based on the SnO_2 electrode has been realized in this study.展开更多
Based on MEMS technology,immunosensor with an'Au,Pt,Pt'three-microelectrode system enclosed in a SU-8 micro pool was fabricated.Employing SAMs technique,the Au electrode was modified by cysteamine(Cys)to assem...Based on MEMS technology,immunosensor with an'Au,Pt,Pt'three-microelectrode system enclosed in a SU-8 micro pool was fabricated.Employing SAMs technique,the Au electrode was modified by cysteamine(Cys)to assemble gold nanopanicles(nanogold)layer,subsequently,a layer of protein G(PG)was immobilized on nanogold layer to further capture antibody orientedly.Compared with the immunosensors using bulky gold electrode and direct PG binding to electrode immobilization technique for antibody,it has attractive advantages,such as miniaturization,good compatibility,broad linear range for human immunoglobulin(HIgG)and easy to be designed into array.展开更多
A new type of disposable thin-film amperometric biosensor has been developed for measurement ofβ-hydroxybutyrate and total cholesterol in serum.The biosensor consists of two plain gold electrodes mounted on a Polyeth...A new type of disposable thin-film amperometric biosensor has been developed for measurement ofβ-hydroxybutyrate and total cholesterol in serum.The biosensor consists of two plain gold electrodes mounted on a Polyethylene terephthalate (PET) substrate.The reagent solution contains bienzymes (cholesterol oxidase and cholesterol esterase for total cholesterol,β-hydroxybutyrate dehydrogenase and diaphorase forβ-hydroxybutyrate respectively) with mediator (ferricyanide) were absorption at the surface of electrodes coated by electrodepositing platinum black.The presence of the mediator lowers the applied potential and eliminates the interference from other oxidizable species enhancing the sensitivity and selectivity of the biosensor without modifying the dynamic parameters of the response.The enzymes stably retains in the matrices of platinum black film improving the performance of the mediated sensor.The linearity is observed in the concentration range from 1.0×10^(-4) to 1.0×10^(-2) mM and 1.0×10^(-4) mM to 4.99×10^(-3) mM with sensitivity of 1.958μA/mM and 2.447μA/mM respectively.The optimized biosensor exhibits excellent reproducibility and stability retaining more than 90% of its original activity over a period of one month.The simple operation of the biosensor mass-produced at low cost is expected to find clinical application and homecare.展开更多
A carbon wire amperometric flow through detector is described which is easily constructed at low cost for application to flow injection analysis,continuous stream analysis and liquid chromatography.The theoretical lim...A carbon wire amperometric flow through detector is described which is easily constructed at low cost for application to flow injection analysis,continuous stream analysis and liquid chromatography.The theoretical limiting current of the detector is 2.14×10~6nCD^(2/3)u_f^(1/3) with 36% actual current efficiency.By use of flow injection analysis,the detecting limits for Ag(I)and Cr(VI)had achieved 1 ppb and 0.4 ppb respectively with 1.2%(n=20)relative standard deviation after preliminary experiments.展开更多
An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagen...An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagent cast and dried on the electrode.The biosensor responses to AST by detecting hydrogen peroxide were produced by enzymical reaction at-0.1 V with a response time of 120 seconds.The electrode gave a detection limit of 32.5 U/L with a linear concentration range of 32.5 U/L～2000 U/L in serum.Due to more sensitive and lower detection limit,the biosensor is expected mainly to be used for physiological identification and physical performance of athletes in the future.Extended application will also affect the practice of clinical medicine for the diagnosis of heart and liver disease.展开更多
A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed electrod...A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed electrodes.The biosensor consisted of an Ag/AgCl reference electrode and a graphite working electrode.The mixture of graphite and the 7,7,8,8-tetracyanoquinodimethane (TCNQ) was printed on electrodes.The detection of organophosphorus pesticides was done with acetylthiocholine chloride (ATCh) as substrate.The biosensor was used to detect the inhibitory effect of organophosphorus pesticides on AChE activity.The 1μl of enzyme solution containing 0.1 U AChE and 1% bovine serum albumin (BSA) were simply dropped on the working electrode surface.The biosensor operated at a potential of 300 mV vs. Ag/AgCl in a pH 7.2 0.1 mol/L phosphate buffer and 0.1 mol/L KCl.We obtained a calibration plot of the percentage inhibition versus the logarithm of parathion methyl concentration following an incubation time of 10 mix in parathion methyl solution. The lowest detectable amount of parathion methyl was 0.026 ppm.The amperometric biosensor based on acetylcholinesterase was disposable and low cost (about 1 yuan RMB).展开更多
A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nation on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide...A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nation on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10^-7 to 6.8×10^-5 mol·L^-1, and the detection limit was 7.2×10^-8 mol·L^-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.展开更多
A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination ...A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination were studied. The data was modified by spline wavelet least square (SWLS). The method is simple, rapid and highly reliable for routine analysis.展开更多
A new type of solid polymer electrolyte based on polyacrylonitrile (PAN )-dimethylsulfoxide (DMSO)-tetrabutylammonium perchlorate (TBAP) system has been prepared. The ionic conductivities of such solid-electrolytes re...A new type of solid polymer electrolyte based on polyacrylonitrile (PAN )-dimethylsulfoxide (DMSO)-tetrabutylammonium perchlorate (TBAP) system has been prepared. The ionic conductivities of such solid-electrolytes reach values as high as 10-4 S. cm-1 at room temperature. At proper content of each component in the solid-electrolyte the polymeric film has a porous network microstructure of three dimen-sions,and exhibits a good level of mechanical properties and dimensional stability. The full-solid-state elec-trochemical cell contains two coplanar electrodes coated by a thin layer of PAN-DMSO-TBAP solid-elec-trolyte: a Au microdisk as working electrode and a Ag ring counter/reference electrode. This study has shown that the integrated two-electrode assembly can be directly used for the amperometric solid-state car-bon dioxide gas sensor devices,and it shows good response characteristics for direct amperometric determi-nation of the CO2 concentration in the gas phase. Also, such full-solid-state amperometric sensor devices possess their own original advantages.展开更多
A simple, fast and reliable method, using high performance anion chromatography with pulsed amperometric detection, had been developed for the analysis of neomycin in water samples. The elution and separation were car...A simple, fast and reliable method, using high performance anion chromatography with pulsed amperometric detection, had been developed for the analysis of neomycin in water samples. The elution and separation were carried out with an isocratic mobile phase, containing 10 mmol/L NaOH. The influence of the concentration and pH of the mobile phase on the separation and detection was investigated. A quadruple-potential waveform used for the detection was optimized. The detection limit of neomycin was down to 0.027 μg/mL. The linearity of neomycin calibration curve ranged from 0.050 to 0.505 μg/mL with correlation coefficient of 0.9997. R.S.D. (n = 11) was 4.0%.展开更多
Copper microelectrodes were used in microvoltammetry to detect histamine and several amino acid neurotransmitters. High sensitivity was obtained through the use of copper microelectrodes, and detection limits of 50 n...Copper microelectrodes were used in microvoltammetry to detect histamine and several amino acid neurotransmitters. High sensitivity was obtained through the use of copper microelectrodes, and detection limits of 50 nmol/L and 90 nmol/L were obtained for histamine and histidine, respectively. Furthermore, histamine and several amino acids neurotransmitters were firstly separated and detected by capillary electrophoresis with amperometric detection on copper microelectrodes. Mass limits of 490 amol and 440 amol were achieved for histamine and histidine, respectively, by using this mothod.展开更多
A cholesterol oxidase from Streptomycin sp. was immobilized onto pencil graphite rod and employed for amperometric determination of serum cholesterol. The method has the advantage over earlier amperometric methods tha...A cholesterol oxidase from Streptomycin sp. was immobilized onto pencil graphite rod and employed for amperometric determination of serum cholesterol. The method has the advantage over earlier amperometric methods that it requires low potential to generate electrons from H2O2, which does not allow ionization of serum substances. The optimum working conditions of amperometric determination were pH 6.8, 25?C and 30 s. The current measured was in proportion to cholesterol concentration ranging from 1.29×10-3 to 10.33×10-3 M. Minimum detection limit of the method was 0.09 ×10-3 M. Mean analytical recovery of added cholesterol (100 mg/dl and 200 mg/dl) in serum was 85.0% & 90.0% respectively. Within batch and between batch coefficients of variations were 1.59% & 4.15% respectively. A good correlation (r = 0.99) was obtained between serum cholesterol values by standard enzymic colorimetric method and the present method. No interference by metabolites was observed in the method. The enzyme electrode was reused 200 times over a period of 25 days, when stored at 4?展开更多
We report a novel bienzyme biosensor based on the assembly of the glucose oxidase (GOD) and horseradish peroxidase (HRP) onto the gold nanoparticles encapsulated mesoporous silica SBA-15 composite (AuNPs-SBA-15). Elec...We report a novel bienzyme biosensor based on the assembly of the glucose oxidase (GOD) and horseradish peroxidase (HRP) onto the gold nanoparticles encapsulated mesoporous silica SBA-15 composite (AuNPs-SBA-15). Electrochemical behavior of the bienzyme bioconjugates biosensor is studied by cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that the presence of mesoporous AuNPs-SBA-15 greatly enhanced the protein loadings, accelerated interfacial electron transfer of HRP and the electroconducting surface, resulting in the realization of direct electrochemistry of HRP. Owing to the electrocatalytic effect of AuNPs-SBA-15 composite, the biosensor exhibits a sensitive response to H2O2 generated from enzymatic reactions. Thus the bienzyme biosensor could be used for the detection of glucose without the addition of any mediator. The detection limit of glucose was 0.5 μM with a linear range from 1 to 48 μM.展开更多
文摘A new capillary electrophoresis apparatus was designed. Piezoelectric ceramics transformer technology was first applied in capillary electrophoresis, a high voltage and stable source was made. Amperometric detector was used in which the working electrode was closely opposite to the end of capillary. The apparatus was characterized in good reproducibility, safety and very low cost.
基金the financial support provided by the National Science Foundation of China(No. 20875032)the Basic Research Fund of the Science and Technology Commission of Shanghai Municipality(No. 09ZR1409700)
文摘A high-performance capillary electrophoresis with amperometric detection(CE-AD) method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum condit...
文摘Response of biosensor prepared with the thermostable bacterial LDH enzyme was analyzed in the presence of mercury and nickel.For electrode preparation,the enzyme was purified and immobilized on a gold sheet coated by PGA-pyrrole polymeric material.The working electrode was tested at increasing concentration of lactate in the presence of two different concentrations of mercury and nickel.Current response of biosensor decreased from 0.32 μA to 0.09 μA and 4.13 μA to 2.63 μA when 25×10-7 mmol/L mercury and 17×10-5 mmol/L nickel were included in the working solution,respectively.Sensitivity of the electrode decreased from 0.010 2 μA/（mmol·L-1） to 0.0043 μA/（mmol·L-1） in the presence of 25×10-7 mmol/L mercury.On the other hand,the presence of nickel did not result in a decrease in electrode sensitivity.The results pointed out that the prepared biosensor is useful to detect mercury in a sample containing both mercury and nickel together.
基金The authors greatly acknowledge the financial support from the National Natural Science Foundation of China （Grant No. 90307014）
文摘A micro amperometric immunosensor with the sensitive area of only 1mm^2 was fabricated on silicon using the technique of Micro-Electro-Mechanical Systems (MEMS).A double exposure of SU-8 photoresist process was developed to create both the sensitive pool and reaction pool.Antibody was immobilized via cross-linking with glutaraldehyde on the sensitive area of the electrode surface,which was electropolymerized with polypyrrole previously.The immunosensor was characterized by detection of human immunoglobulin G (HIgG).The immunosensor displayed a good linear response to HIgG concentrations between 5ng/ml and 255ng/ml and demonstrated a fast response time of 3 minutes.
基金supported by National Natural Science Foundation of China,No.90307014
文摘A circuit model of the Amperometric immunosensor for use in the biosensor system-on-chip simulation is proposed in this paper.The model parameters are extracted with several methods and verified by MATLAB and SPICE simulation.A CMOS potentiostat circuit required for conditioning the Amperometric immunosensor is also included in the circuit model.The mean square error norm of the simulated curve against the measured one is 8.65×10^(-17) The whole circuit has been fabricated in a 0.35μm CMOS process.
基金Supported by the Key L aboratory of Electroanalytical Chemistry,Changchun Institute of Applied Chem istry of Chi-nese AcademyofSciences
文摘The present paper covers a simple, reliable and reproducible method, based on capillary zone electrophoresis(CZE) with amperometric detection(AD), for the separation and the determination of ephedrine hydrochloride, promethazine hydrochloride and codeine phosphate. Under the optimal conditions, the three analytes were base-line separated completely within 16 min. Good linear relationships between the peak heights and the concentrations of the three analytes were obtained with the correlation coefficients better than 0 9993. The method was directly applied to the determination of the active ingredients in pharmaceutical preparations and the assay results were satisfactory.
文摘An amperometric glucose biosensor based on a tin oxide (SnO_2) electrode has been developed.The SnO_2 electrode is prepared by depositing the SnO_2 thin film onto a carbon electrode.To fabricate the SnO_2 amperometric glucose biosensor,the glucose oxidase and electron transfer mediator (ferrocenecarboxylic acid,FcA) are coimmobilized on the SnO_2 electrode using polyacrylamide.The detection range is up to glucose concentration of 520mg/dl as the applied potential is set at 300mV. Moreover,the most merit for the SnO_2 electrode as the base electrode of the SnO_2 amperometric glucose biosensor is that it can be operated at 150mV constant applied potential.The interference reduction,detection range,sensitivity and linearity are improved as the SnO_2 thin film is deposited onto a carbon electrode.Furthermore,due to the low cost substrate and simple fabrication characteristics,a disposable amperometric glucose biosensor based on the SnO_2 electrode has been realized in this study.
基金This work is supported by the National Natural Science Foundation of China （Grant No. 90307014）.
文摘Based on MEMS technology,immunosensor with an'Au,Pt,Pt'three-microelectrode system enclosed in a SU-8 micro pool was fabricated.Employing SAMs technique,the Au electrode was modified by cysteamine(Cys)to assemble gold nanopanicles(nanogold)layer,subsequently,a layer of protein G(PG)was immobilized on nanogold layer to further capture antibody orientedly.Compared with the immunosensors using bulky gold electrode and direct PG binding to electrode immobilization technique for antibody,it has attractive advantages,such as miniaturization,good compatibility,broad linear range for human immunoglobulin(HIgG)and easy to be designed into array.
文摘A new type of disposable thin-film amperometric biosensor has been developed for measurement ofβ-hydroxybutyrate and total cholesterol in serum.The biosensor consists of two plain gold electrodes mounted on a Polyethylene terephthalate (PET) substrate.The reagent solution contains bienzymes (cholesterol oxidase and cholesterol esterase for total cholesterol,β-hydroxybutyrate dehydrogenase and diaphorase forβ-hydroxybutyrate respectively) with mediator (ferricyanide) were absorption at the surface of electrodes coated by electrodepositing platinum black.The presence of the mediator lowers the applied potential and eliminates the interference from other oxidizable species enhancing the sensitivity and selectivity of the biosensor without modifying the dynamic parameters of the response.The enzymes stably retains in the matrices of platinum black film improving the performance of the mediated sensor.The linearity is observed in the concentration range from 1.0×10^(-4) to 1.0×10^(-2) mM and 1.0×10^(-4) mM to 4.99×10^(-3) mM with sensitivity of 1.958μA/mM and 2.447μA/mM respectively.The optimized biosensor exhibits excellent reproducibility and stability retaining more than 90% of its original activity over a period of one month.The simple operation of the biosensor mass-produced at low cost is expected to find clinical application and homecare.
基金This Project is supported by the National Science Foundation of China
文摘A carbon wire amperometric flow through detector is described which is easily constructed at low cost for application to flow injection analysis,continuous stream analysis and liquid chromatography.The theoretical limiting current of the detector is 2.14×10~6nCD^(2/3)u_f^(1/3) with 36% actual current efficiency.By use of flow injection analysis,the detecting limits for Ag(I)and Cr(VI)had achieved 1 ppb and 0.4 ppb respectively with 1.2%(n=20)relative standard deviation after preliminary experiments.
文摘An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagent cast and dried on the electrode.The biosensor responses to AST by detecting hydrogen peroxide were produced by enzymical reaction at-0.1 V with a response time of 120 seconds.The electrode gave a detection limit of 32.5 U/L with a linear concentration range of 32.5 U/L～2000 U/L in serum.Due to more sensitive and lower detection limit,the biosensor is expected mainly to be used for physiological identification and physical performance of athletes in the future.Extended application will also affect the practice of clinical medicine for the diagnosis of heart and liver disease.
文摘A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed electrodes.The biosensor consisted of an Ag/AgCl reference electrode and a graphite working electrode.The mixture of graphite and the 7,7,8,8-tetracyanoquinodimethane (TCNQ) was printed on electrodes.The detection of organophosphorus pesticides was done with acetylthiocholine chloride (ATCh) as substrate.The biosensor was used to detect the inhibitory effect of organophosphorus pesticides on AChE activity.The 1μl of enzyme solution containing 0.1 U AChE and 1% bovine serum albumin (BSA) were simply dropped on the working electrode surface.The biosensor operated at a potential of 300 mV vs. Ag/AgCl in a pH 7.2 0.1 mol/L phosphate buffer and 0.1 mol/L KCl.We obtained a calibration plot of the percentage inhibition versus the logarithm of parathion methyl concentration following an incubation time of 10 mix in parathion methyl solution. The lowest detectable amount of parathion methyl was 0.026 ppm.The amperometric biosensor based on acetylcholinesterase was disposable and low cost (about 1 yuan RMB).
基金This research was supported by the National Natural Science Foundation of China. （Nos. 60571042 and 30370397）
文摘A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nation on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10^-7 to 6.8×10^-5 mol·L^-1, and the detection limit was 7.2×10^-8 mol·L^-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.
基金This work was supported by the National Natural Science Foundation of China and Guang Dong Provincial Natural Science Foundation(29675033 and 20175037 001237)
文摘A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination were studied. The data was modified by spline wavelet least square (SWLS). The method is simple, rapid and highly reliable for routine analysis.
文摘A new type of solid polymer electrolyte based on polyacrylonitrile (PAN )-dimethylsulfoxide (DMSO)-tetrabutylammonium perchlorate (TBAP) system has been prepared. The ionic conductivities of such solid-electrolytes reach values as high as 10-4 S. cm-1 at room temperature. At proper content of each component in the solid-electrolyte the polymeric film has a porous network microstructure of three dimen-sions,and exhibits a good level of mechanical properties and dimensional stability. The full-solid-state elec-trochemical cell contains two coplanar electrodes coated by a thin layer of PAN-DMSO-TBAP solid-elec-trolyte: a Au microdisk as working electrode and a Ag ring counter/reference electrode. This study has shown that the integrated two-electrode assembly can be directly used for the amperometric solid-state car-bon dioxide gas sensor devices,and it shows good response characteristics for direct amperometric determi-nation of the CO2 concentration in the gas phase. Also, such full-solid-state amperometric sensor devices possess their own original advantages.
文摘A simple, fast and reliable method, using high performance anion chromatography with pulsed amperometric detection, had been developed for the analysis of neomycin in water samples. The elution and separation were carried out with an isocratic mobile phase, containing 10 mmol/L NaOH. The influence of the concentration and pH of the mobile phase on the separation and detection was investigated. A quadruple-potential waveform used for the detection was optimized. The detection limit of neomycin was down to 0.027 μg/mL. The linearity of neomycin calibration curve ranged from 0.050 to 0.505 μg/mL with correlation coefficient of 0.9997. R.S.D. (n = 11) was 4.0%.
文摘Copper microelectrodes were used in microvoltammetry to detect histamine and several amino acid neurotransmitters. High sensitivity was obtained through the use of copper microelectrodes, and detection limits of 50 nmol/L and 90 nmol/L were obtained for histamine and histidine, respectively. Furthermore, histamine and several amino acids neurotransmitters were firstly separated and detected by capillary electrophoresis with amperometric detection on copper microelectrodes. Mass limits of 490 amol and 440 amol were achieved for histamine and histidine, respectively, by using this mothod.
文摘A cholesterol oxidase from Streptomycin sp. was immobilized onto pencil graphite rod and employed for amperometric determination of serum cholesterol. The method has the advantage over earlier amperometric methods that it requires low potential to generate electrons from H2O2, which does not allow ionization of serum substances. The optimum working conditions of amperometric determination were pH 6.8, 25?C and 30 s. The current measured was in proportion to cholesterol concentration ranging from 1.29×10-3 to 10.33×10-3 M. Minimum detection limit of the method was 0.09 ×10-3 M. Mean analytical recovery of added cholesterol (100 mg/dl and 200 mg/dl) in serum was 85.0% & 90.0% respectively. Within batch and between batch coefficients of variations were 1.59% & 4.15% respectively. A good correlation (r = 0.99) was obtained between serum cholesterol values by standard enzymic colorimetric method and the present method. No interference by metabolites was observed in the method. The enzyme electrode was reused 200 times over a period of 25 days, when stored at 4?
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20635020 & 90606016)
文摘We report a novel bienzyme biosensor based on the assembly of the glucose oxidase (GOD) and horseradish peroxidase (HRP) onto the gold nanoparticles encapsulated mesoporous silica SBA-15 composite (AuNPs-SBA-15). Electrochemical behavior of the bienzyme bioconjugates biosensor is studied by cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that the presence of mesoporous AuNPs-SBA-15 greatly enhanced the protein loadings, accelerated interfacial electron transfer of HRP and the electroconducting surface, resulting in the realization of direct electrochemistry of HRP. Owing to the electrocatalytic effect of AuNPs-SBA-15 composite, the biosensor exhibits a sensitive response to H2O2 generated from enzymatic reactions. Thus the bienzyme biosensor could be used for the detection of glucose without the addition of any mediator. The detection limit of glucose was 0.5 μM with a linear range from 1 to 48 μM.
