A novel nano crystalline Ag2O2-PbO2 film chemically modified electrode (CME) was prepared and the CME was characterized by X-ray diffractometer (XRD) and atomic force microscope (AFM). By chronoamperometry, the nano A...A novel nano crystalline Ag2O2-PbO2 film chemically modified electrode (CME) was prepared and the CME was characterized by X-ray diffractometer (XRD) and atomic force microscope (AFM). By chronoamperometry, the nano Ag2O2-PbO2 CME was used as bioelectro- chemical sensor to determine the population of Escherichia coli (E. coli) in water. Compared with conventional methods, it is found that the technique we used is fast and convenient in counting E. coli.展开更多
A magnetic bar carbon paste electrode （MBCPE） modified with Fe3O4 magnetic nanoparticles （Fe3O4NPs） and 2‐（3,4‐dihydroxyphenyl） benzothiazole （DPB） for the electrochemical determina‐tion of hydrazine was de...A magnetic bar carbon paste electrode （MBCPE） modified with Fe3O4 magnetic nanoparticles （Fe3O4NPs） and 2‐（3,4‐dihydroxyphenyl） benzothiazole （DPB） for the electrochemical determina‐tion of hydrazine was developed. The DPB was firstly self‐assembled on the Fe3O4NPs, and the re‐sulting Fe3O4NPs/DPB composite was then absorbed on the designed MBCPE. The MBCPE was used to attract the magnetic nanoparticles to the electrode surface. Owing to its high conductivity and large effective surface area, the novel electrode had a very large current response for the electrocat‐alytic oxidation of hydrazine. The modified electrode was characterized by voltammetry, scanning electron microscopy, electrochemical impedance spectroscopy, infrared spectroscopy, and UV‐visible spectroscopy. Voltammetric methods were used to study the electrochemical behaviour of hydrazine on MBCPE/Fe3O4NPs/DPB in phosphate buffer solution （pH = 7.0）. The MBCPE/Fe3O4NPs/DPB, acting as an electrochemical sensor, exhibited very high electrocatalytic activity for the oxidation of hydrazine. The presence of DPB was found to reduce the oxidation potential of hydrazine and increase the catalytic current. The dependence of the electrocatalytic current on the hydrazine concentration exhibited two linear ranges, 0.1–0.4 μmol/L and 0.7–12.0 μmol/L, with a detection limit of 18.0 nmol/L. Additionally, the simultaneous determination of hydrazine and phe‐nol was investigated using the MBCPE/Fe3O4NPs/DPB electrode. Voltammetric experiments showed a linear range of 100–470 μmol/L and a detection limit of 24.3 μmol/L for phenol, and the proposed electrode was applied to the determination of hydrazine and phenol in water samples.展开更多
A novel type of Fe3O4 nanoparticles modified glass carbon electrode（Fe3O4/GCE） was constructed and the electrochemical properties of N-（4-nitro-2-phenoxyphenyl）methanesulfonamide（nimesulide） were studied on the ...A novel type of Fe3O4 nanoparticles modified glass carbon electrode（Fe3O4/GCE） was constructed and the electrochemical properties of N-（4-nitro-2-phenoxyphenyl）methanesulfonamide（nimesulide） were studied on the Fe3O4/GCE.In 0.4mol/L HAc-NaAc buffer solution（pH=5.0）,the electrode process of nimesulide was irreversible at bare GCE and Fe3O4/GCE.The Fe3O4/GCE exhibited a remarkable catalytic and enhancement effect on the reduction of nimesulide.The reduction peak potential of nimesulide shifted positively from-0.683 V at bare GCE to-0.625 V at Fe3O4/GCE,and the sensitivity was increased by ca.3 times.Some experimental conditions were optimized.The linear range between the peak current and the concentration of nimesulide was 2.6×10-6 ＂1.0×10-4mol/L（R=0.993） with a detection limit of 1.3×10-7mol/L.This method has been used to determine the content of nimesulide in medical tablets.The recovery was determined to be 96.9% ＂101.9% by means of standard addition method.The method is comparable to UV-Vis spectrometry.展开更多
Non-enzymatic biosensors based on mixed transition metal oxides are deemed as the most promising devices due to their high sensitivity,selectivity,wide concentration range,low detection limits,and excellent recyclabil...Non-enzymatic biosensors based on mixed transition metal oxides are deemed as the most promising devices due to their high sensitivity,selectivity,wide concentration range,low detection limits,and excellent recyclability.Spinel NiCo2O4 mixed oxides have drawn considerable attention recently due to their outstanding advantages including large specific surface area,high permeability,short electron,and ion diffusion pathways.Because of the rapid development of non-enzyme biosensors,the current state of methods for synthesis of pure and composite/hybrid NiCo2P4 materials and their subsequent electrochemical biosensing applications are systematically and comprehensively reviewed herein.Comparative analysis reveals better electrochemical sensing of bioanalytes by one-dimensional and two-dimensional NiCo2O4 nano-/microstructures than other morphologies.Better biosensing efficiency of NiCo2O4 as compared to corresponding individual metal oxides,viz.NiO and Co3O4,is attributed to the close intrinsic-state redox couples of Ni3+/Ni2+(0.58 V/0.49 V) and Co3+/Co2+(0.53 V/0.51 V).Biosensing performance of NiCo2O4 is also significantly improved by making the composites of NiCo2O4 with conducting carbonaceous materials like graphene,reduced graphene oxide,carbon nanotubes(single and multi-walled),carbon nanofibers;conducting polymers like polypyrrole(PPy),polyaniline(PANI);metal oxides NiO,Co3O4,SnO2,MnO2;and metals like Au,Pd,etc.Various factors affecting the morphologies and biosensing parameters of the nano-/microstructured NiCo2O4 are also highlighted.Finally,some drawbacks and future perspectives related to this promising field are outlined.展开更多
基金We are greateful to the National Narural Science Foundation of China(No.20455017)Science and Technology Committee of Shanghai Municipal(No.0452nm084).
文摘A novel nano crystalline Ag2O2-PbO2 film chemically modified electrode (CME) was prepared and the CME was characterized by X-ray diffractometer (XRD) and atomic force microscope (AFM). By chronoamperometry, the nano Ag2O2-PbO2 CME was used as bioelectro- chemical sensor to determine the population of Escherichia coli (E. coli) in water. Compared with conventional methods, it is found that the technique we used is fast and convenient in counting E. coli.
文摘A magnetic bar carbon paste electrode （MBCPE） modified with Fe3O4 magnetic nanoparticles （Fe3O4NPs） and 2‐（3,4‐dihydroxyphenyl） benzothiazole （DPB） for the electrochemical determina‐tion of hydrazine was developed. The DPB was firstly self‐assembled on the Fe3O4NPs, and the re‐sulting Fe3O4NPs/DPB composite was then absorbed on the designed MBCPE. The MBCPE was used to attract the magnetic nanoparticles to the electrode surface. Owing to its high conductivity and large effective surface area, the novel electrode had a very large current response for the electrocat‐alytic oxidation of hydrazine. The modified electrode was characterized by voltammetry, scanning electron microscopy, electrochemical impedance spectroscopy, infrared spectroscopy, and UV‐visible spectroscopy. Voltammetric methods were used to study the electrochemical behaviour of hydrazine on MBCPE/Fe3O4NPs/DPB in phosphate buffer solution （pH = 7.0）. The MBCPE/Fe3O4NPs/DPB, acting as an electrochemical sensor, exhibited very high electrocatalytic activity for the oxidation of hydrazine. The presence of DPB was found to reduce the oxidation potential of hydrazine and increase the catalytic current. The dependence of the electrocatalytic current on the hydrazine concentration exhibited two linear ranges, 0.1–0.4 μmol/L and 0.7–12.0 μmol/L, with a detection limit of 18.0 nmol/L. Additionally, the simultaneous determination of hydrazine and phe‐nol was investigated using the MBCPE/Fe3O4NPs/DPB electrode. Voltammetric experiments showed a linear range of 100–470 μmol/L and a detection limit of 24.3 μmol/L for phenol, and the proposed electrode was applied to the determination of hydrazine and phenol in water samples.
基金Supported by the National Natural Science Foundation of China(No.21065001)the Natural Science Foundation of Guangxi Province,China(Nos.0639025,0991084)+2 种基金the Support Program for 100 Young and Middle-aged Disciplinary Leaders in Higher Education Institutions of Guangxi Province,China(No.RC20060703005)the Project of Key Laboratory of Development and Application of Forest Chemicals of Guangxi Province,China(No.GXFC08-06)the Fund of Education Department of Guangxi Province,China(No.200812MS074)
文摘A novel type of Fe3O4 nanoparticles modified glass carbon electrode（Fe3O4/GCE） was constructed and the electrochemical properties of N-（4-nitro-2-phenoxyphenyl）methanesulfonamide（nimesulide） were studied on the Fe3O4/GCE.In 0.4mol/L HAc-NaAc buffer solution（pH=5.0）,the electrode process of nimesulide was irreversible at bare GCE and Fe3O4/GCE.The Fe3O4/GCE exhibited a remarkable catalytic and enhancement effect on the reduction of nimesulide.The reduction peak potential of nimesulide shifted positively from-0.683 V at bare GCE to-0.625 V at Fe3O4/GCE,and the sensitivity was increased by ca.3 times.Some experimental conditions were optimized.The linear range between the peak current and the concentration of nimesulide was 2.6×10-6 ＂1.0×10-4mol/L（R=0.993） with a detection limit of 1.3×10-7mol/L.This method has been used to determine the content of nimesulide in medical tablets.The recovery was determined to be 96.9% ＂101.9% by means of standard addition method.The method is comparable to UV-Vis spectrometry.
文摘Non-enzymatic biosensors based on mixed transition metal oxides are deemed as the most promising devices due to their high sensitivity,selectivity,wide concentration range,low detection limits,and excellent recyclability.Spinel NiCo2O4 mixed oxides have drawn considerable attention recently due to their outstanding advantages including large specific surface area,high permeability,short electron,and ion diffusion pathways.Because of the rapid development of non-enzyme biosensors,the current state of methods for synthesis of pure and composite/hybrid NiCo2P4 materials and their subsequent electrochemical biosensing applications are systematically and comprehensively reviewed herein.Comparative analysis reveals better electrochemical sensing of bioanalytes by one-dimensional and two-dimensional NiCo2O4 nano-/microstructures than other morphologies.Better biosensing efficiency of NiCo2O4 as compared to corresponding individual metal oxides,viz.NiO and Co3O4,is attributed to the close intrinsic-state redox couples of Ni3+/Ni2+(0.58 V/0.49 V) and Co3+/Co2+(0.53 V/0.51 V).Biosensing performance of NiCo2O4 is also significantly improved by making the composites of NiCo2O4 with conducting carbonaceous materials like graphene,reduced graphene oxide,carbon nanotubes(single and multi-walled),carbon nanofibers;conducting polymers like polypyrrole(PPy),polyaniline(PANI);metal oxides NiO,Co3O4,SnO2,MnO2;and metals like Au,Pd,etc.Various factors affecting the morphologies and biosensing parameters of the nano-/microstructured NiCo2O4 are also highlighted.Finally,some drawbacks and future perspectives related to this promising field are outlined.
