43 results about "Differential pulse voltammetry" patented technology

The application relates to the field of electrochemical analysis methods, and particularly discloses a preparation method of an electrode capable of simultaneously detecting amaranth, carmine and indigo and application of the electrode; the electrode preparation method is as follows: firstly, Fe / Co Prussian blue seed modified carbon fiber paper is prepared through a chemical deposition method; secondly, the Fe / Co Prussian blue seed modified carbon fiber paper is subjected to a hydrothermal reaction to prepare hollow cubic octahedral Fe / Co Prussian blue nanomaterial modified carbon fiber paper electrode; finally, the hollow cubic octahedral Fe / Co oxide nanomaterial modified carbon fiber paper electrode (CoFe2O4@CFP) is obtained through calcination. The CoFe2O4@CFP electrode is used as a working electrode, and the content of the three pigments, i.e. amaranth, carmine and indigo, in a sample to be detected can be simultaneously detected by adopting a differential pulse voltammetry method combined with a chronoamperometry method. Compared with other methods, the method has the advantages of simple preparation, rapid detection, wide application in simultaneous determination of amaranth, carmine and indigo in actual samples such as candies, tap water and beverages, high detection sensitivity, wide detection range and great practical application potential.

This invention belongs to the field of electrochemical testing technology and discloses a dual-plate portable electrochemical testing system, including an upper plate, a lower plate, an electrochemical biosensor electrode converter, and a mobile terminal APP. The invention adopts an upper and lower plate structure, separating the data programming surface and the sensor interface surface, facilitating the replacement and upgrading of computing resources and the analog front-end separately. The invention hierarchically lays out the three-electrode interface analog circuit and the communication control circuit, and separates the power supply for digital and analog power supplies, which helps reduce mutual interference between the sensor's analog signal lines and digital communication signal lines, improving the stability of electrochemical testing. This invention enables wireless interaction via a mobile terminal and can be portablely powered by an external terminal device, offering flexible usage and facilitating on-site deployment and mobile testing. This invention supports multiple testing modes, including cyclic voltammetry, chronoamperometry, and differential pulse voltammetry, adapting to different electrochemical testing needs.

An electrochemical method for detecting, identifying, and quantifying ions and nutrients dissolved in water through voltammetry, and equipment to carry out the method, including: a preparation / placement stage of a sensor, with a reference electrode, working electrode, and counter electrode, in a potentiostat; a stage for contacting a sample or analysis solution containing the analyte with the sensor; a stage for applying, controlled via software from a computer system, electrical stimulation to the sample through Cyclic Voltammetry, Normal Pulse Voltammetry, Differential Pulse Voltammetry, or Square Wave Voltammetry, with a step potential and pulse amplitude range between −3,000 mV and 3,000 mV; and a stage for characterizing one or more analytes based on at least one measurement of the signals resulting from the oxidation-reduction of the analyte(s).

This invention discloses a method for quantitatively detecting muscle inositol in blood. It employs an electrochemical method and specifically includes the following steps: a) preparation of a series of standard working solutions; b) preparation of a blank sample solution; c) plotting a standard curve using differential pulse voltammetry (DPV) with the blank sample solution and the series of standard working solutions; d) preparation of the test sample solution; e) determination of the muscle inositol content in the test sample. Experiments have demonstrated that the method of this invention yields accurate and reliable results and can be used for clinical blood testing.

The invention provides a triple signal amplification electrochemical method for detecting a porcine reproductive and respiratory syndrome virus NADC30-like strain. Firstly, the surface of a gold electrode is modified with a hairpin signal probe H1, when a target sequence appears, the hairpin H1 is opened, a sequence capable of triggering a hybridization chain reaction (HCR) is exposed, long dsDNA is formed, and first signal amplification is achieved. Then, under the catalysis of terminal deoxynucleotidyl transferase (TdT), a large amount of polythymine (PolyT) extends from 3'terminal hydroxyl groups of H2 and H3 fragments, and second signal amplification is realized; polyT serves as a template, in-situ deposition of a large amount of CuNPs is caused in a short time, the signal response of the electrochemical sensor is remarkably enhanced, and third signal amplification is achieved. And finally, monitoring metal ions released by dissolution of the nanoparticles by using a differential pulse voltammetry, and drawing a standard curve through current change to realize accurate quantification of the target virus. The method is high in sensitivity and good in specificity, and can be used for general detection of viruses by replacing a target virus specific sequence and a corresponding probe.

The invention relates to a method for electrochemically detecting chloramphenicol by using molecular imprinting. The method is characterized in that a chloramphenicol molecularly imprinted polymer prepared from a temperature-sensitive monomer N-isopropylacrylamide and Dawson type tungsten phosphate (P2W18) are jointly modified on a substrate electrode through a simple and controllable electrostatic layer-by-layer self-assembly method. The modified electrode synthesized by the method disclosed by the invention is used as a working electrode, a saturated calomel electrode is used as a reference electrode, a platinum electrode is used as an auxiliary electrode, and the electrochemical sensing performance of the modified electrode on chloramphenicol is respectively evaluated by cyclic voltammetry, differential pulse voltammetry and square wave voltammetry. According to the modified electrode, the sensitivity of an electrochemical signal is synergistically enhanced through the high-selectivity imprinting cavity of the molecularly imprinted polymer and the rapid and reversible oxidation-reduction activity of P2W18, the detection linear range of chloramphenicol is 0.1 nM to 10 [mu] M, and the detection limit of differential pulse voltammetry is as low as 0.145 nM; and a good application prospect is provided for preparing a uniform and controllable molecularly imprinted polymer composite modified electrode material in the future. At present, an indissolvable molecularly imprinted polymer material is integrated into an electrochemical sensor through an electrostatic layer-by-layer self-assembly technology, so that the research on improving the selectivity of chloramphenicol detection and reducing the detection limit is rarely reported.

The application discloses an air bacterial electrostatic collection and real-time monitoring system and method integrated with a microfluidic portable sensor, and belongs to the technical field of environmental monitoring, and comprises an aerosol sampling module, a microfluidic processing module, an electrochemical sensing module and a portable constant potential instrument module. Bacteria aerosols in the ambient air are charged by corona discharge to realize efficient enrichment and collection; the enriched liquid sample is sent into the microfluidic processing module and flows through a sensing electrode modified with CuFeCoPBA@MoS2 nano composite material, polydopamine and concanavalin A. Target bacteria are combined with the concanavalin A on the surface of the electrode in a broad-spectrum specific manner, the interface electron transfer is hindered, the portable constant potential instrument collects the attenuation change of differential pulse voltammetry electrochemical signals, and rapid quantitative detection of the concentration of air bacteria is completed. The application integrates efficient air aerosol collection and portable biosensing, and can realize one-step on-site capture and detection of air pathogens.

The invention relates to a preparation method of a carteolol hydrochloride determination electrode and a quantitative analysis method of the carteolol hydrochloride determination electrode. The cetyl trimethyl ammonium bromide / nano zinc oxide-multi-walled carbon nanotube composite electrode is prepared by taking a glassy carbon electrode as a matrix. An electrochemical workstation is used as a signal acquisition device, the electrode is used as a working electrode, a saturated Ag / AgCl electrode is used as a reference electrode, a platinum wire is used as a counter electrode, and after a substance to be measured is subjected to open-circuit pre-enrichment, the content of carteolol hydrochloride in urine is measured by using cyclic voltammetry and differential pulse voltammetry. Application results show that the substance has a good linear relationship in a range of 1 * 10 <-3 >-2 * 10 <-1 > g.L <-1 >, the detection limit can reach 2 * 10 <-4 > g.L <-1 >, and the recovery rate is 96.5-110.5%. The method has a certain anti-interference capability.

The application relates to the technical field of detection, in particular to a general foodborne pathogenic bacteria detection method suitable for a long-distance sailing environment. UiO-66 is used to enrich methylene blue, and is combined with target bacteria aptamer to obtain UiO-66 / MB / Aptamer which simultaneously serves as a signal amplification and recognition probe. A membrane separation method is used to filter out the probes not combined with the bacteria. The electrochemical signal of methylene blue is detected by using a differential pulse voltammetry method, a corresponding linear relationship is constructed, and the concentration of the bacteria is quantitatively detected. The application not only guarantees the sensitivity, detection time, portability and other characteristics of the detection of foodborne pathogenic bacteria, but also provides a general detection method for detecting various target bacteria. Through the reproducibility and stability test under the high-temperature, high-humidity and high-salt environment, it is proved that the application can realize the rapid, sensitive and stable detection of foodborne pathogenic bacteria in a complex long-distance sailing environment.

The application provides a kind of electrochemical immune sensing detection method for fruit and vegetable organochlorine pesticide multi-residue, belongs to the technical field of food safety detection, comprising: using liquid pulse discharge plasma synchronous reduction method to prepare g-C3N4-COOH / AuNPs heterojunction composite material with lattice coupling interface and modify on the surface of silk screen printing carbon electrode, through click chemistry reaction, azide modified organochlorine antigen is covalently fixed on the electrode surface, and the labeled immune probe loaded with different electrochemical signal substances and different organochlorine pesticide specific antibodies is used for competitive immune reaction, the differential pulse voltammetry response curve in the whole potential interval is collected, a plurality of characteristic parameters are extracted, and the concentration of multiple organochlorine pesticides is simultaneously solved by using partial least squares multivariate correction model.The application solves the problems of low interface electron transport efficiency, uncontrollable antigen fixation orientation, serious interference of complex matrix and difficult multi-residue signal resolution in the prior art.

The invention discloses a lead ion ultra-trace detection method based on a non-mercury film modified microarray electrode technology, which comprises the following steps: providing a microarray working electrode composed of a plurality of glassy carbon microelectrode units, and carrying out mechanical polishing and / or electrochemical activation on the exposed surface of the microarray working electrode; the microarray working electrode, a reference electrode and a counter electrode are jointly placed in a modification solution containing a non-mercury electroactive substance, a continuous non-mercury electroactive film layer is formed on the exposed surface of each glassy carbon microelectrode unit through electrochemical deposition, and the non-mercury electroactive film layer is in direct electric contact with a glassy carbon substrate; placing the microarray working electrode modified by the non-mercury electroactive film layer, a reference electrode and a counter electrode in a buffer electrolyte, and carrying out electrochemical cleaning; a to-be-detected sample and a buffer solution are mixed to form a to-be-detected solution, the to-be-detected solution is put into a three-electrode system, anodic stripping scanning is conducted through differential pulse voltammetry or square wave voltammetry, and the lead ion concentration in the sample is determined. The method does not need complex pretreatment, the detection limit reaches 0.1 mu M (20 mu g / L), and lead ions in complex matrixes such as clinical serum and the like can be rapidly and accurately detected.

This invention discloses a method for preparing a magnetic organic framework-ionic liquid composite material and its application. The main components of this magnetic organic framework-ionic liquid composite material are iron(III) oxide nanoparticles, zeolite imidazole framework-8, and an ionic liquid. It is immiscible with ethanol, exhibiting aggregated droplet form in ethanol. After shaking and dispersion, it can rapidly recombine into droplets. Furthermore, the material possesses adsorption properties for heavy metal ions, enabling the removal of Cd ions from ethanol. 2+ Cu 2+ Hg 2+ Simultaneous adsorption of three heavy metal ions. These ions are magnetically adsorbed onto the surface of a magnetic glassy carbon electrode, enabling one-step electrode surface material modification. Subsequently, differential pulse voltammetry can be used to achieve the adsorption of Cd ions. 2+ Cu 2+ Hg 2+ Simultaneous electrochemical detection of three heavy metal ions.

The application discloses a kind of electrochemical sensor based on cerium vanadate nanorod intercalation MXene composite material and its preparation method and application, belong to electrochemical sensor technical field.The working electrode of the sensor is formed by the composite material modified glassy carbon electrode that cerium vanadate nanorod is uniformly inserted and embedded in MXene interlayer and surface.The preparation method includes: Ti3AlC2 is etched by hydrofluoric acid, and MXene is obtained by ultrasonic stripping;Vanadate nanorod is synthesized by hydrothermal method;Different mass ratios of MXene / CeVO4 material are obtained by ultrasonic-assisted compounding;Electrode is modified by drop coating method.Rutin is detected in phosphate buffer solution with pH=4.0 by differential pulse voltammetry, the linear range is 0.1~11 μmol / L, and the detection limit is 0.052 μmol / L.The sensor has high sensitivity, low detection limit, good reproducibility, stability and anti-interference ability, and can be used for rapid detection of rutin content in drug tablets.

The invention discloses application of magnetic cobalt / nitrogen-doped porous carbon in diclofenac analysis, and belongs to the field of drug residue detection. And performing high-temperature pyrolysis on the precursor ZIF-67 to obtain the magnetic cobalt / nitrogen-doped porous carbon (CNC). The product is used as a magnetic solid-phase extraction adsorbent to separate and enrich diclofenac in a sample to be detected, and is also used as an electrode modification material to amplify an electrochemical signal of diclofenac, then differential pulse voltammetry electrochemical detection is performed, the operation is simple, the reagent consumption is low, and the detection time is short.

The application discloses a biosensor and a method for detecting NF-kappa B p50, comprising: an electrode, wherein a DNA tetrahedron structure is combined on the surface of the electrode; the DNA tetrahedron structure is used for being combined with a detection probe DNA; the detection probe DNA comprises a detection probe DNA nucleic acid sequence and an electrochemiluminescence group connected with the detection probe DNA nucleic acid sequence. The biosensor can realize reversible dissociation of the detection probe DNA under alkaline conditions, thereby supporting at least 10 repeated detection cycles without affecting detection sensitivity and specificity. The detection method adopts a differential pulse voltammetry method, combines with a side branch cutting signal amplification strategy of a CRISPR-Cas12a system, and realizes high-sensitivity detection of the NF-kappa B p50. The method is suitable for complex biological samples, has high sensitivity, high specificity and good repeated use performance, and the minimum detection limit can reach 100 femtomolar level, and the linear detection range covers 100 aM to 80000 aM.

The invention provides an electrochemical method for rapidly detecting uric acid and application thereof, and the electrochemical method comprises the following steps: S1, mixing a diluted sample with a Fe3O4 (at) PDA-PB suspension according to a volume ratio of (8-10): 1 by using a microinjection pump to form a mixed sample, and injecting the mixed sample into a pretreated microfluidic chip sample injection area at a flow rate of 5-10 [mu] L / min; s2, enabling the mixed sample obtained in the step S1 to flow through a magnetic separation area, specifically combining Fe3O4 (at) PDA-PB with uric acid in the sample, and adsorbing the Fe3O4 (at) PDA-PB on a channel wall under the action of a magnetic field to realize separation from interferents; s3, enabling the sample purified in S2 to flow into a detection area fixed with a modified electrode, standing for 1-1.5 min, starting differential pulse voltammetry scanning, accelerating uric acid oxidation through a catalyst layer of a working electrode, and recording uric acid oxidation peak current; and S4, after detection, enabling the solution to flow into a waste liquid area, and flushing the micro-fluidic chip with a phosphate buffer solution for three times. The method can effectively meet the requirement for uric acid detection in clinical or batch scenes, and is particularly suitable for early warning of subclinical hyperuricemia.

The invention discloses a method for detecting hexachlorobutadiene in a water body, and belongs to the technical field of electrochemical sensing detection. According to the method, thiophene is used as a functional monomer, hexachlorobutadiene is used as a template molecule, a molecularly imprinted membrane solution containing hexachlorobutadiene is polymerized to the surface of a working electrode through an electrochemical polymerization method, and hexachlorobutadiene in a water body is determined through a differential pulse voltammetry method. The method has the advantages of high sensitivity, low detection limit, short detection time and the like.

The invention discloses a polyaniline intercalation copper modified electrode material for detecting dopamine, and belongs to the technical field of electrochemical analysis. The polyaniline intercalation copper modified electrode material disclosed by the invention is generated by polymerizing copper acetate and aniline under the oxidation of ammonium persulfate; the polyaniline intercalation copper modified electrode material can be used for detecting dopamine through differential pulse voltammetry. The preparation method disclosed by the invention is simple, low in cost and low in environmental pollution index; the prepared modified electrode material can realize rapid, sensitive and high-selectivity electrochemical detection on dopamine, and has a potential application prospect.

The application discloses a kind of MIP / WS2-AC@Cu-MOF-199 modified glassy carbon electrode and its preparation method and electrochemical sensing detection perfluorooctane method, with MIP / WS2-AC@Cu-MOF-199 modified glassy carbon electrode as working electrode, Ag / AgCl electrode as reference electrode, platinum as auxiliary electrode, potassium ferricyanide / potassium ferrocyanide as charged probe molecule, and water PFOA is detected quickly using differential pulse voltammetry.The application will tungsten sulfide-activated carbon (WS2-AC) and Cu-MOF (199) are simply modified by ball milling, to strengthen the conductivity of original Cu-MOF material, to establish a simple and low-cost electrochemical sensing detection method.This method has simple detection, raw material source is extensive, and the method can effectively detect PFOA in a wide range and maintain good sensitivity.The application provides a kind of water perfluorooctane sensing detection method based on electrochemistry using MOF material, and has good application prospect.

This invention discloses a ratiometric electrochemical sensor, its preparation method, and a method for simultaneously detecting methyl parathion and carbendazim. The sensor uses a CeCoZn-MOF / NBA / CNHs-modified glassy carbon electrode as the working electrode, a saturated KCl-type Ag / AgCl as the reference electrode, and a platinum wire as the counter electrode. Preparation involves electrode pretreatment, CeCoZn-MOF synthesis, composite material compounding, dispersion preparation, and electrode drop-coating modification. Differential pulse voltammetry is used for detection, with Nile Blue A as the internal standard probe. Quantification is based on the current ratio of the target analyte to the internal standard. The linear detection range for methyl parathion is 0.05–15 μg / mL, and for carbendazim, it is 0.05–4 μg / mL, with correlation coefficients greater than 0.99 for both. This sensor exhibits strong anti-interference capabilities, high sensitivity and accuracy, with a recovery rate of 91.0%–109.2% in actual agricultural product samples. It enables rapid, simultaneous, and accurate detection of methyl parathion and carbendazim, and is suitable for rapid on-site detection of pesticide residues in agricultural products.

This invention discloses a dual-recognition electrochemical sensor, its preparation method, and its application. The sensor comprises: (1) a working electrode modified with a molecularly imprinted polymer membrane; and (2) a vancomycin-modified copper-based metal-organic framework nanoenzyme signal probe. This signal probe specifically binds to the cell wall of Gram-positive bacteria and catalyzes the oxidation of o-phenylenediamine by peroxide to generate an electrochemical signal. During detection, the target bacteria are first captured by the molecularly imprinted layer, and the signal probe binds to the bacterial cell via vancomycin, forming a "sandwich" structure. The change in current signal is detected by differential pulse voltammetry to achieve quantitative analysis. The sensor of this invention has a detection limit as low as 1.1 CFU / mL and a linear range of 4 × 10⁻⁶. 1 -4×10 8 The CFU / mL concentration exhibits good selectivity and stability in complex samples such as cerebrospinal fluid. The preparation method of this invention is simple, low-cost, and highly sensitive, and can be used for ultrasensitive detection of Listeria monocytogenes in fields such as central nervous system infections and food safety monitoring.

The invention relates to the technical field of electrochemical sensing, and discloses a Bi2Se3 / Ti3C2Tx sweat heavy metal electrochemical sensor and a preparation method thereof, and the preparation method comprises the following steps: preparing a Bi2Se3 / Ti3C2Tx composite material from a Ti3C2Tx nanosheet and a Bi2Se3 nanoflower material through an electrostatic self-assembly method, and modifying the Bi2Se3 / Ti3C2Tx composite material on the surface of a working electrode platform by adopting a micro dispensing method to prepare the lead-cadmium ion electrochemical sensor. Connecting the lead-cadmium ion electrochemical sensor into a circuit, performing electrochemical quantitative determination by adopting differential pulse voltammetry, and calculating the contents of Pb < 2 + > and Cd < 2 + > in sweat according to a peak current value; a machine learning method is used, a hybrid model fusing a least square lifting algorithm and a northern eagle optimization algorithm is adopted, and key experimental parameters of the sensor for detecting Pb < 2 + > and Cd < 2 + > are optimized.

The application discloses an electrochemical sensor fusing local hairpin self-assembly and metal nanoparticle cooperative amplification strategies, which utilizes the characteristics that nano metal and thiol are easy to combine to fix DNA base column probe S1 on the electrode surface. Then, S1 and HP1, two kinds of nucleic acid probes, are modified on the nano metal particles, and auxiliary probe HP2 and nucleic acid TS to be detected are added, local hairpin self-assembly reaction occurs among the three, a plurality of metal nanoparticles are connected with each other through nucleic acid probes S1 and HP1. The multistage structure is connected with S1 on the electrode surface, which promotes a large number of oxidation-reduction signal molecules to be gathered on the electrode surface in a short time, and multistage amplification is realized. Finally, the differential pulse voltammetry in the electrochemical technology is utilized to convert the substance amount of the oxidation-reduction signal molecules into the current signal in proportion, and high-sensitivity and large-range nucleic acid detection sensing is completed. In actual detection, the lowest detectable amount of some microRNA is in the order of fM.

The present application relates to the technical field of detection of foodborne pathogenic bacteria, and particularly relates to a biosensor based on VS2 nanocomposite material, a preparation method and application. The biosensor is constructed, wherein the biosensor comprises an electrode part and a probe part, the electrode part is GCE / AuNPs / Ab1 / BSA, and the probe part is VS2 / AuNPs / PEI-Fc. The electrode part is mixed with a to-be-tested liquid for incubation, and after washing with PBS buffer, GCE / AuNPs / Ab1 / BSA / SH is obtained. Then, the electrode part is mixed with the to-be-tested liquid for incubation, and after washing with PBS buffer, the biosensor GCE / AuNPs / Ab1 / BSA / SH / Ab2 / PEI-Fc / AuNPs / VS2 is obtained. The obtained biosensor is placed in a PBS solution, and an electric signal is measured by using a differential pulse voltammetry (DPV) method, so that the target object can be detected. The signal value of the biosensor is positively correlated with the concentration of the target object. The biosensor has high detection sensitivity, and in the range of 0-1 μg / mL, the detection limit is as low as 1.1 pg / mL, and the linear correlation coefficient of the prediction model reaches 0.958.

The invention discloses an imidacloprid high-sensitivity rapid electrical analysis detection method based on a carbon nanosensor, and relates to the field of chemical analysis. The preparation method comprises the following steps: firstly, mixing a carbon nanotube and hexa [(trimethylsilyl) ethynyl] benzene in N, N-dimethylformamide, and continuously stirring; then adding CuCl, heating in a reaction kettle at 60 DEG C for 24 hours, filtering, washing and drying to obtain carbon nanotube-graphdiyne; dispersing the carbon nanotube at graphdiyne in ultrapure water, performing uniform ultrasonic treatment to obtain a suspension liquid, dropwise adding the suspension liquid to the surface of a polished glassy carbon electrode, and drying to obtain a modified electrode material, namely the carbon nanotube at graphdiyne / glassy carbon electrode; and preparing a to-be-detected solution containing a to-be-detected substance imidacloprid, finally inserting the modified electrode substance carbon nanotube and graphdiyne / glassy carbon electrode into the to-be-detected solution, and carrying out concentration determination by adopting a differential pulse voltammetry. According to the invention, rapid and high-sensitivity detection of imidacloprid is finally realized through preparation of the carbon nanotube-graphdiyne material, electrode modification and electrochemical determination in sequence.

The invention discloses a molecularly imprinted electrochemical sensor for detecting tacrolimus. An electrochemical polymerization method is adopted, tacrolimus is used as a template molecule, o-phenylenediamine and chloroauric acid are used as functional monomers, electrochemical copolymerization is carried out on the surface of a gold electrode, and poly-o-phenylenediamine and gold nanoparticles are generated. And eluting the template molecules, and preparing the organic / inorganic hybrid containing the target molecular imprinting on the surface of the gold electrode. The gold electrode with the surface modified with the hybrid is immersed in a base solution containing potassium ferricyanide, and a three-electrode system of an electrochemical workstation is adopted for detecting redox signals through an electrochemical cyclic voltammetry method and a differential pulse voltammetry method. Samples containing different concentrations of tacrolimus are dropwise added to the surface of the modified electrode, and then the modified electrode is immersed in a base solution to measure the redox signal intensity of the modified electrode. The relationship between the concentration of the tacrolimus and the corresponding electrochemical signal intensity is established, and then the molecularly imprinted electrochemical sensor is developed and is used for efficiently detecting the tacrolimus.

The present application belongs to the technical field of electrochemical detection, and particularly relates to an enrofloxacin aptamer sensor based on a screen-printed electrode and a rapid detection method. The present application first prepares Fe / Co two-dimensional MOF nanosheets with a sheet structure by a room temperature stirring method, then incubates the nanosheets with enrofloxacin aptamer to prepare nanosheet / aptamer probes, further incubates the probes with enrofloxacin, and mixes with acetic acid-sodium acetate buffer, o-phenylenediamine and H2O2 to form a catalytic reaction system. In combination with a screen-printed electrode-differential pulse voltammetry method, the enrofloxacin concentration of a sample to be tested is quickly tested by drawing a quantitative analysis standard working curve, so that rapid, simple and high-sensitivity detection of enrofloxacin is realized. The present application is simple and rapid to operate, does not require expensive reagents, large instruments and professional operators, has high sensitivity, and can realize on-site, rapid, high-sensitivity and quantitative detection of enrofloxacin in fish and shrimp and other aquatic products at the grassroots level in combination with a portable electrochemical detector.

The invention provides a multiple miRNA detection electrochemical biosensor, a preparation method, a product and application, and belongs to the technical field of electrochemical detection. The multiple miRNA detection electrochemical biosensor is developed on the basis of an amino-functionalized nano material or a modified avidin nano material, and a specific capture probe and a signal probe marked with different metal ions or biotin are designed; by combining electrochemical detection methods such as two-step sandwich type hybridization reaction and differential pulse voltammetry or square wave voltammetry, quantitative simultaneous detection of multiple miRNAs is realized, the detection process is simplified, the detection efficiency is improved, and the problem that multiple markers cannot be simultaneously detected by a traditional method is solved. In addition, by optimizing hybridization reaction conditions and probe design, the specificity of the sensor is improved, cross reaction is reduced, meanwhile, the stability and reproducibility of detection results are guaranteed, and finally an efficient and accurate tool is provided for clinical detection of miRNA.

This invention discloses an electrochemical sensor for rapid detection of catechins, its preparation method, and its application, belonging to the field of electrochemical sensing technology. The sensor uses a screen-printed electrode as a substrate, and its working electrode surface is modified with a composite nanomaterial formed by the co-assembly of 5-(hydroxyphenyl)-10,15,20-phenylporphyrin and multi-walled carbon nanotubes. The preparation method includes: preparing TPP-OH solution and MWCNT dispersion separately, mixing them, and then performing a co-assembly reaction to obtain the composite material. This material is then dispersed and drop-coated onto the surface of the screen-printed electrode. When using this sensor, differential pulse voltammetry is employed to achieve quantitative detection of catechins by measuring the current response value of the characteristic oxidation peak. This invention's sensor is simple to prepare, low in cost, and exhibits advantages such as high sensitivity, good selectivity, rapid response, and a wide linear range for catechin detection. It can be used for the rapid analysis of catechins in salt-tolerant plants such as wild soybean.

The invention relates to a method for determining an electrochemical signature of a liquid, the method comprising a step, referred to as a current variation measurement step, consisting in measuring the variation in current in the liquid using a working electrode during a potential sweep carried out using a differential pulse voltammetry technique, the pulses of which each have an amplitude of between 5 mV and 200 mV and a duration of between 1 ms and 60 ms, the potential step of which is between 1 mV and 30 mV, and the sweep speed of which is between 5 mV.s-1 and 50 mV.s-1.