129 results about "Chronoamperometry" patented technology

The present invention relates to devices and methods of use thereof for making semiderivative voltammetric and chronoamperometric measurements of chemicals, e.g. neurotransmitters, precursors, and metabolites, in vitro, in vivo, or in situ. The invention relates to methods of diagnosing and/or treating a subject as having or being at risk of developing a disease or condition that is associated with abnormal levels of one or more neurotransmitters including, inter alia, epilepsy, diseases of the basal ganglia, athetoid, dystonic diseases, neoplasms, Parkinson's disease, brain injuries, spinal cord injuries, and cancer. The invention provides methods of differentiating white matter from grey matter using microvoltammetry. In some embodiments, regions of the brain to be resected or targeted for pharmaceutical therapy are identified using Broderick probes. The invention further provides methods of measuring the neurotoxicity of a material by comparing Broderick probe microvoltammograms of a neural tissue in the presence and absence of the material.

The invention discloses a carbon-containing metal catalyst, a preparation method and an application thereof. The catalyst uses carbon fiber material as a carrier, and uses sodium borohydride, methanol or glycol as a reducing agent. One or several of chloroplatinic acid, chloroauric acid, and other metal precursors are mixed and then reduced to obtain a metal/carbon nanofiber catalyst for fuel cells, preferably with a metal loading amount being 10-60 wt %. The catalyst is high in initially electrochemically active surface area, and relatively small in current density attenuation during a 120-minute chronoamperometry test, has a current density higher than that of present commercial platinum catalyst/XC72R (40 %) during a whole electrochemical chronoamperometry test, and shows relatively high electrochemical activity, relatively high current density and relatively superior electrochemical stability. The catalyst show extremely high resistance to carbon monoxide toxicity.

The invention relates to a graphene quantum dot modified electrochemical sensor, and a preparation method and application thereof. A three-electrode system is adopted for the sensor, and a graphene quantum dot modified gold electrode is taken as a working electrode. Chemical bonds are used for bonding carboxylic groups of graphene quantum dots and amino groups on the surface of the modified gold electrode to construct the graphene quantum dot modified electrochemical sensor. The graphene quantum dot modified gold electrode is taken as the working electrode, and chronoamperometry is used for determining a working curve of H2O2 concentration. The linear range of the H2O2 concentration is determined to be 2 mu M to 8mM, and a detection lower limit is 1.3 mu M. In addition, the sensor can be used for detecting the content of H2O2 released by living cells in real time, has the advantages of quick response, wide linear range, low detection lower limit, broad application prospect and the like, and is significant for diagnostic tests in diseases caused by reactive oxygen species (ROS).

The present invention relates to an electrochemical biosensor for detecting hydrogen peroxide, a preparation method and an application thereof. The preparation method comprises the steps of (1) synthesizing the silica-three-dimensional graphene composite material; (2) doping nitrogen and carbon into the synthesized silica-three-dimensional graphene composite material; (3) pretreating a glassy carbon electrode; (4) preparing the glassy carbon electrode modified by the nitrogen-carbon-doped silica-three-dimensional graphene composite material through the dispensing method; (5) putting the glassy carbon electrode into a chloroauric acid solution to prepare gold nanoparticle-nitrogen-carbon-doped silica-three-dimensional graphene glassy carbon electrode through chronoamperometry; (6) dipping the glassy carbon electrode into a double-sulfhydryl-modified GDNA solution and cultivating for 2-4 hours; (7) dipping the composite electrode into a hemin solution for 10-14 hours. The electrochemical biosensor is good in stability and reproducibility, high in specificity and sensitivity, fast and simple and convenient to operate. The electrochemical biosensor can be used for detecting the content of hydrogen peroxide in biological samples, cosmetics and the like.

The invention relates to a method for depositing nano-silver in microfluidic channels. The method comprises the steps that ITO glass is pretreated, and ITO glass with (PDDA/PSS) n multilayer self-assembled films is prepared; the ITO glass serves as a substrate and is connected with a chip made of PDMS in an encapsulating mode to form a microfluidic chip, then a NaNO3 and AgNO3 mixed solution is injected into microfluidic channels, nano-silver is deposited in the microfluidic channels with chronoamperometry, and nano-silver surface morphology detection shows that nano-silver particles distributed evenly can be seen in the microfluidic channels. The method has the advantages of being quick, simple, high in repeatability, low in cost and the like, and has wide application prospects in the fields such as medical bio-engineering and medical biosensors.

The invention relates to a composite carbon fiber-loaded metal catalyst as well as a preparation method and application thereof. The composite carbon fiber-loaded metal catalyst is high in graphitization degree, good in catalyst metal particle dispersion performance and excellent in catalytic performance and is prepared by adopting a transitional metal oxide as a graphitization enhancer of a carbon material and a metal dispersion loading induction agent. The prepared composite carbon fiber material loaded with the transitional metal oxide is catalyzed through the transitional metal oxide under the high temperature condition to obtain a carbon material with a high graphitization degree, and the transitional metal oxide composite carbon fiber material is used as a catalyst carrier to be reduced by a reduction agent. The catalyst is high in initial electrochemical activity surface area and good in duration, and after the catalyst is cycled for 4500 times, the electrochemical active surface area sill can be maintained at 54 percent. The current density attenuation is reduced in a timing current-method electrochemical test of 120 minutes, the electrochemical activity is high, the current density is high, and the duration is excellent.

The invention belongs to the technical field of electrochemical sensors, and in particular relates to an Au(111)-like nano-particle modified non-enzyme glucose sensor electrode, and a preparation method and application of the same. The preparation method comprises the following steps of: firstly, wiping a conductive substrate with alcohol, then, respectively performing ultrasonic washing with acetone, isopropyl alcohol and ultrapure water, adding the conductive substrate in the mixed liquor of deionized water, ammonia water and hydrogen peroxide, heating until boiling, finally, cleaning the conductive substrate with the ultrapure water and blowing the conductive substrate to dry with nitrogen; in the electrolyte solution composed of sodium perchlorate and chloroauric acid solution, firstly, performing electrolytic deposition on the conductive substrate by means of chronoamperometry, then, further performing electrolytic deposition on the conductive substrate by means of cyclic voltammetry, and cleaning the conductive substrate with the deionized water. The non-enzyme glucose sensor electrode is very sensitive to the concentration variation of the glucose and presents better linear relation, moreover, the non-enzyme glucose sensor electrode has better selectivity to the glucose, only needs 1.5s response time to the glucose and can achieve the detection limit of 5mu moL/L.

The invention discloses a method for detecting hydrogen peroxide and nitrite by an electrochemical sensor based on a dual-metal porphyrin coordination polymer. A dual-metal porphyrin coordination polymer (CoTCPP-Cu or CoTCPP-Cu/CNTs) composite material modification electrode is used as a working electrode; hydrogen peroxide or nitrite is detected by a timing current method; CoTCPP-Cu is a coordination polymer assembled by dual metals Co and Cu and tetra-(p-carboxyphenyl) porphyrin. The electrochemical sensor adopted in the method is a current type sensor, has unique dual-metal activity and is high in sensitivity; the method has the advantages of convenience in detection and wide application range; the detection limit for hydrogen peroxide can reach 5.0*10<-7>M and the detection limit for nitrite can reach 2.5*10<-6>. The detection method disclosed by the invention has the characteristics of quick on-site detection, high sensitivity, low cost and the like.

The invention discloses a carbon-carrier precious metal catalyst for fuel cell, a preparation method thereof and an application thereof. The catalyst uses band-shaped nanometer carbon as the carrier, sodium borohydride, methanol or glycol as a reducing agent, and co-reduces the band-shaped nanometer carbon and the precious metal acid or the precious metal salts to obtain the precious metal/band-shaped nanometer carbon catalyst for the fuel cell, preferably a platinum loading amount being 10-60 wt %. The catalyst is high in initial electrochemical active surface area, relatively small in current density attenuation during a chronoamperometry test, and relatively high in current density during an electrochemical timing current test compared with that of present catalysts, and shows relatively high electrochemical activity, relatively high current density and relatively excellent electrochemical stability.

The present invention relates to a method of producing an electrodeposited metal oxide coating for a supercapacitor electrode. The present invention relates to the chronoamperometric electrodeposition of the metal oxide over a period from a few seconds, up to about 30 seconds leading to superior performance as a result of an increased surface area of the deposit. According to the present invention, the capacitances achieved are typically greater than 1300 F/g, and in some instances, over 4000 F/g.

The invention relates to a method for testing hydrogen peroxide in a cell based on a horseradish peroxidase-attapulgite nanometer composite material; the method comprises the following steps: horseradish peroxidase is adsorbed on the surface of purified attapulgite so as to prepare the horseradish peroxidase-attapulgite nanometer composite material; a dispensing method is used for applying the composite material to the surface of a glassy carbon electrode so as to construct a horseradish peroxidase-attapulgite nanometer composite material biological sensor; the sensor is used as a working electrode; and a chronoamperometry is used for detecting H2O2 in the cell. The biological sensor adopted by the method for testing the hydrogen peroxide in the cell has good electrical catalytic activity on hydrogen peroxide, can be applied to the detection of H2O2 in the cell and has the advantages of fast response, wide linear range, low detection limit, good repeatability and the like; and a new electrochemistry method based on enzyme sensing for detecting H2O2 in the cell is established.

The invention relates to an electrochemical reduction-oxidation graphene modified electrode and application thereof in detection of heavy metal sexivalent chromium ions in water thereof. The modifiedelectrode is prepared by directly depositing electrochemical reduction-oxidation graphene on the surface of a working electrode. The sexivalent chromium ions are detected by using chronoamperometry, linear sweep voltammetry or cyclic voltammetry, the graphene modified electrode serves as a working electrode, an Ag/AgCl electrode serves as a reference electrode, a platinum electrode serves as the counter electrode, and experimental parameter setting is detected. The graphene modified gold electrode serves as the working electrode, the electrode preparation process is simple and convenient, andthe prepared electrode has high electrochemical activity, is capable of realizing rapid detection Cr (VI), wide in detection range (5-2000ug/L) and low in lower limit of detection (0.5 ug/L), has theadvantages of resistance to interference of other metal ions, stability, short detection cycle and the like, and is expected to be applied to actual portable detection application in future.

The invention belongs to the fieldss of electrochemistry and fiber materials. In the invention, anodic oxidation treatment or surface electropolymerization treatment are carried out on CF by adopting a chronoamperometry method in an external electric field under an external voltage of 0.5-6 V at a reaction temperature of 20-35 DEG C for a reaction time of 5-150 s. In case of the anodic oxidation treatment, acid, alkali or ammonium salt is adopted as an electrolyte which has the concentration ranging from 0.1-5mol/L. In case of the surface electropolymerization treatment, maleic anhydride is adopted as an elemental solution which has the concentration of 0.1-2mol / L. In the invention, by modifying the CF surface through anodic oxidation or surface electropolymerization, the surface oxygen content and the roughness of the CF surface are improved so that the hydrophilicity and the microbial affinity of the CF surface are improved and the applications of the CF as a biofilm carrier to the sewage treatment field by using a biofilm method are facilitated.

A universal portable detector for an electrochemical biosensor takes a microcontroller integrating functions of digital-to-analog conversion and analog-to-digital conversion together as a core, wherein, a peripheral circuit comprises a power management module, a constant potential module, an E<2>PROM memory, a clock manager, a temperature sensor, a buzzer, a keypad input module and an LCD module;and the universal portable detector can be matched with the common varied electrochemical biosensors with a three-electrode system or a two-electrode system, particularly a chip of the small-sized orminiature electrochemical biosensor to realize chronoamperometry, chronocoulometry and multiple voltammetry detection functions, and meanwhile the detector can perform temperature correction on a detection result. The universal portable detector takes high integration level, low power consumption and practicability as a design principle; the detector has small volume and convenient power supply with a battery, thus having portability; and the detector is applicable to on-spot analysis in the fields such as medical detection, food security, environmental protection and the like, thus meeting the requirement for fast detection.

The method consists in registering curves by cyclic voltammetry method in the range of copper ion concentration up to 20 g/l or alternately by chronoamperometric method in the range of concentration from 20 to 60 g/l. A platinum or gold microprobe of a diameter in the range from 1 to 50 um and a copper plate reference electrode are used. The value of current density read off from said curves is compared to the calibration curves previously determined by standard additions method. For high concentration in the range from 20 to 60 g/l the calibration curves obtained in the range of temperatures from 15 to 60° C. are registered.

The invention discloses a preparation method of nitrogen doped graphene quantum dots with high dispersion in a water phase and an application. The preparation method comprises the following steps: anaqueous solution of tetrabutylammonium hydroxide is used as an electrolyte; a graphite rod with high purity is used as a working electrode, a platinum wire electrode is used as a counter electrode, acalomel electrode is used as a reference electrode, and fixed potential chronoamperometry is used for electrolysis of the graphite rod; an electrolytic solution is filtered in order to remove a graphene slice layer, a dialysis bag is used for dialysis, in order to obtain the nitrogen doped graphene quantum dots with high dispersion in a water phase. The preparation method has the advantages of simple process, cheap and easily available raw materials, and short preparation time; the nitrogen doped graphene quantum dots have the characteristics of good dispersion in water phase, long fluorescentlifetime, high quantum yield, good biocompatibility, and the like; and the nitrogen doped graphene quantum dots have good application prospects in the fields of fluorescence detection of life samplesand imaging.

Electropolymerization of EC monomers is employed to obtain an EC polymer film deposited on a substrate. A first embodiment of a method to produce the film employs cyclic voltammetry alone, while a second embodiment deposits a very thin homogeneous layer using chronoamperometry, and then cyclic voltammetry is employed to increase the density of the film. Another aspect of the present invention is directed to specific web like configurations for a grid of conductive material deposited onto a transparent substrate. The web like configuration is based either on concentric circles, or on concentric ellipses. Yet another aspect of the present invention is directed to an imaging system including a digital window that is disposed between a prism and a patterned analytic layer.

The invention relates to a method for detecting glucose based on a cobalt-based metal organic framework enzyme-free glucose sensor. The method is carried out by adopting the cobalt-based metal organicframework enzyme-free glucose sensor, and comprises the following steps: (1) establishing a three-electrode system by taking the cobalt-based metal organic framework enzyme-free glucose sensor as a working electrode; (2) fitting and drawing a calibration curve according to a current response value corresponding to glucose concentration; 3) determining the content of glucose in the to-be-determined solution. The method is based on the cobalt-based metal organic framework enzyme-free glucose sensor, and an electrochemical workstation and a three-electrode system are adopted for detection, so rapid and accurate detection of glucose is achieved through a chronoamperometry. The detection method is high in detection speed, stable current can be achieved within 5 seconds, and operation is easy and convenient. The detection limit is low (1.6 [mu]M), the linear range is wide (5-900 [mu]M), the influence of temperature and pH is avoided, the detection range is wide, and the sensitivity can reach 169 [mu]A*mM<-1>*cm<-2>.

The invention discloses a preparation method of a molecular imprinting electrochemical sensor for detecting serotonins. The preparation method comprises the following steps: carrying out polishing and washing pre-treatment on a glassy carbon electrode; preparing a sulfuric acid solution containing rGO; adding aniline and mixing sufficiently to prepare an electric polymerization solution; immersing the glassy carbon electrode into the electric polymerization solution and carrying out electric polymerization reaction; reacting and drying to obtain an rGO/PANI composite film modified electrode; preparing a PBS (Phosphate Buffer Solution) containing functionalized gold nano grains, amino thiophenol and the serotonins and standing the solution to obtain a molecular imprinting self-assembling solution; inserting the rGO/PANI composite film modified electrode into the molecular imprinting self-assembling solution; carrying out the electric polymerization reaction by using a chronoamperometry; and immersing the electrode into the sulfuric acid solution to be treated to obtain the molecular imprinting electrochemical sensor for detecting the serotonins. According to the preparation method, the electrical conductivity of the surface of the electrode is improved by the sensor, the detection sensitivity and the selectivity to the serotonins are improved, and the sensitivity of the molecular imprinting sensor is enhanced.

The invention relates to a flexible electrode based on a flower-like nanogold structure and a preparation method thereof, and belongs to the technical field of electronic materials. The flexible electrode is characterized in that ITO (Indium Tin Oxide) glass is self-assembled layer by layer, electrochemical gold deposition is carried out on the assembled ITO glass by adopting chronoamperometry, alayer of golden flower-like nanogold will deposit on the ITO glass after the electrochemical deposition, and the golden flower-like nanogold depositing on the ITO glass is called ITO-Au; used electrolyte is a KAuCl4 and H2SO4 mixed solution, a reference electrode is an Ag/AgCl electrode, a counter electrode is a platinum wire, and a working electrode is the assembled ITO glass; the ITO glass requires to be cleaned before assembling. A cleaning process is characterized by carrying out ultrasonic cleaning by respectively using deionized water, acetone and ethanol. The flexible electrode preparedby the invention has lower square resistance, and good electrical conductivity still can be kept after bending for many times and stretching for many times.

The invention belongs to the technical field of medical biomaterials, and discloses a nano-structure polypyrrole/biotin composite material based on a conductive base material, a preparation method and application. The preparation method for the nano-structure polypyrrole/biotin composite material based on the conductive base material comprises the steps that firstly, the chlorine-doped polypyrrole is electro-deposited on the surface of the conductive base material by adopting chronoamperometry; then a three-electrode mode is selected, conductive metal is a counter electrode, the conductive base material with the polypyrrole deposited on the surface is a working electrode, an electrolyte is a buffer solution containing pyrrole and biotin, and chronopotentiometry is adopted so as to obtain the nano-structure polypyrrole/biotin composite material based on the conductive base material; when the buffer solution is neutral, a nano-cone-structure polypyrrole/biotin material is deposited on the surface of the working electrode; and when the buffer solution is acidic or alkaline, a nano-particle-structure polypyrrole/biotin material is deposited on the surface of the working electrode. The preparation method is simple, the cost is low, the nano structure of the prepared composite material is stable, and the preparation method can be used for preparing materials for efficiently capturing and releasing circulating tumor cancer cells.