74 results about "Differential pulse voltammetry" patented technology

The invention relates to a preparation method and application of an electrochemical sensor for detecting norfloxacin in water, a boron-doped diamond (BDD) electrode is modified by adopting a multi-walled carbon nanotube and gold nanoparticles, and the sensitivity of the electrode is enhanced; and preparing a layer of molecular imprinting film on the surface of a boron-doped diamond (BDD) electrode by taking norfloxacin as an imprinting molecule and adopting an electrochemical in-situ electropolymerization technology, so as to improve the specificity of the electrode and construct an electrochemical sensor for detecting norfloxacin in water. The MIP / AuNPs / MWCNTs / BDD electrode is immersed into norfloxacin buffer solutions with different concentrations for 10 min, and then a differential pulse method DPV is used for testing to obtain a peak current and concentration corresponding relation curve; therefore, the selectivity of the electrode is improved, and the influence of other interfering substances is reduced. Meanwhile, the sensitivity and the stability of the electrode are enhanced, and trace substances are detected.

The invention discloses a biosensor and a method for detecting NF-kB p50, the biosensor comprises: an electrode, the surface of which is bound with a DNA tetrahedral structure; the DNA tetrahedral 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 electrochemical luminescence group connected with the detection probe DNA nucleic acid sequence. The biosensor can realize reversible dissociation of detection probe DNA under an alkaline condition, so that at least 10 times of repeated detection cycles are supported, and the detection sensitivity and specificity are not influenced. According to the detection method, a differential pulse voltammetry is adopted, a collateral cleavage signal amplification strategy of a CRISPR-Cas12a system is combined, high-sensitivity detection of NF-kappa B p50 is achieved, the method is suitable for complex biological samples and has high sensitivity, high specificity and good reuse performance, the lowest detection limit can reach the 100 fly mole level, and the linear detection range covers 100 aM to 80000 aM.

The invention belongs to the technical field of biochemical detection, and particularly relates to a bionic microsphere, a non-diagnostic-purpose extracellular vesicle detection method and an extracellular vesicle detection kit, the bionic microsphere is prepared by modifying a homologous cell membrane CM on the surface of a silica microsphere MS; the bionic microsphere (CMS) is used for capturing specific types of extracellular vesicles (EVs) in a to-be-detected sample and an optical / electrochemical detection method, can specifically capture homologous EVs, and is combined with fluorescence, ultraviolet visible absorption, differential pulse voltammetry and electrochemical luminescence for detection.

The invention relates to the technical field of detection and identification of fentanyl substances, and discloses a selective quantitative detection method of fentanyl. According to the method, a differential pulse voltammetry (DPV) is used for making a linear relation diagram of a potassium ferricyanide peak current and fentanyl solutions with different concentrations to obtain a standard working curve, a linear equation is obtained through the standard curve, and the detection limit is 1.0 * 10 <-12 > mol.L <-1 >; the molecularly imprinted membrane modified electrode prepared by the invention is used for measuring the peak current of a potassium ferricyanide solution, so that fentanyl molecules can be indirectly and quantitatively analyzed and measured. The method is characterized in that a fentanyl molecularly imprinted membrane is electrically polymerized on the surface of a glassy carbon electrode, m-phenylenediamine is used as a functional monomer, and the selectivity and sensitivity of an electrochemical method for detecting fentanyl are improved. Meanwhile, by taking an adsorption pulse stripping voltammetry (DPASV) as a detection technology, a method capable of rapidly detecting fentanyl molecules in the presence of various drugs is established. The molecularly imprinted membrane electrode disclosed by the invention is simple to prepare, quick in response and good in selectivity and reproducibility, and can be repeatedly used for more than five times.

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).

The invention discloses an electrochemical sensor based on COFs and carbon nanotube compounding and a preparation method and application thereof. The preparation method comprises the following steps: carrying out Schiff base condensation on 6-formyl triphenyl benzene (THPD) and 1, 2-diaminobenzene (BE) or 2, 5-dimethyl-1, 4-phenylenediamine (DBE) under proper reaction conditions to obtain a three-dimensional COFs material (respectively marked as THPD-BE and THPD-DBE) with an lnj topological structure; and mixing the obtained COFs with a multi-walled carbon nanotube according to a certain ratio to prepare a functional composite electrode, thereby forming the electrochemical sensor for simultaneously detecting DNA basic groups guanine (G) and adenine (A). The sensor has abundant pore structures and active sites, and shows high sensitivity, low detection limit, wide linear range and good stability in combination with excellent conductivity of the carbon nanotubes. Clear oxidation peaks of guanine and adenine can be respectively obtained at 0.88 V and 0.62 V through differential pulse voltammetry (DPV), and signals of guanine and adenine do not interfere with each other, so that high-precision simultaneous detection of guanine and adenine is realized.

The invention discloses a preparation method and application of a double-signal amplification unmarked electrochemical sensor for simultaneously detecting Pb < 2 + > and Hg < 2 + >. The sensor comprises a screen-printed electrode, a Ti3C2-Au layer and a MnO-SC layer, wherein the Ti3C2-Au layer and the MnO-SC layer are sequentially modified on the surface of the screen-printed electrode from inside to outside, and the MnO-SC layer is formed by annealing sulfur-containing Mn-MOF. The application of the sensor comprises detection of Pb < 2 + > and Hg < 2 + > in river water and tap water. Wherein the redox peaks of Pb < 2 + > and Hg < 2 + > are used as index signals, and no extra signal label is required to be introduced. When Pb < 2 + > and Hg < 2 + > are detected, the MnO-coated SC / Ti3C2-Au / SPEC modified electrode is used as a working electrode, the Ag / AgCl electrode is used as a reference electrode, the carbon electrode is used as an auxiliary electrode, and differential pulse voltammetry is adopted for detection. The linear range of the sensor is 0.25-50 [mu] M, and the detection limits of the sensor are 26.7 nM and 20.1 nM respectively. The sensor prepared by the invention shows excellent selectivity, reliability and repeatability on Pb < 2 + > and Hg < 2 + > in river water and tap water.

The present invention provides an electrochemical pre-activation detection method for identifying isomers of aromatic nitro compounds, belonging to the field of electrochemical detection. Specifically, when performing differential pulse voltammetry (DPV) electrochemical detection on isomers of aromatic nitro compounds, the isomers of aromatic nitro compounds are first electrochemically pre-activated. Electrochemical pre-activation means applying a negative potential first, and the isomers of aromatic nitro compounds are reduced to isomers of aromatic nitroso compounds. The isomers of aromatic nitroso compounds further undergo redox reactions to generate isomers of aromatic hydroxylamine compounds. When using DPV electrochemical detection for redox reactions, the peak positions of the isomers are spaced relatively far apart, thereby achieving effective identification and detection of isomers of aromatic nitro compounds.

The invention relates to the technical field of electrochemical analysis, in particular to an electrochemical sensor for detecting fisetin and an electrochemical method.The electrochemical sensor comprises a working electrode, the working electrode is Nafion-AuNPs / CFME, the Nafion-AuNPs / CFME comprises CFME, a Nafion layer and an AuNPs layer, and the Nafion layer and the AuNPs layer are sequentially modified on the surface of the CFME; the electrochemical sensor is adopted, a to-be-detected sample is detected through cyclic voltammetry or differential pulse voltammetry, response current is recorded, and then the concentration of fisetin in the to-be-detected sample is calculated according to a concentration-current linear regression equation. According to the electrochemical sensor, Nafion-AuNPs / CFME is adopted as a working electrode, the modification effect of AuNPs on the surface of CFME is enhanced through Nafion, and high-sensitivity, high-selectivity and wide-concentration-range detection of fisetin can be achieved.

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 application discloses a method for detecting the freshness of large yellow croaker based on a Ti3C2Tx@CeO2 electrochemical sensor, and has the characteristics that the method comprises the following steps: placing the Ti3C2Tx@CeO2 electrochemical sensor in a large yellow croaker sample solution to be detected, testing the peak current at a xanthine characteristic peak of 0.75 V and the peak current at a malondialdehyde characteristic peak of 0.95 V by using a differential pulse voltammetry method, and calculating the concentration values of xanthine and malondialdehyde in the large yellow croaker sample to be detected according to the linear relationship between the xanthine concentration and the peak current at 0.75 V and the linear relationship between the malondialdehyde concentration and the peak current at 0.95 V, respectively, so that the method has the advantages of simultaneously detecting multiple freshness indexes, high synchronous detection capability, high sensitivity, low detection limit, simplicity and quickness, high specificity and high accuracy.

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 invention discloses an electrochemical detection method for circulating tumor DNA in a human body and application thereof, and the electrochemical detection method comprises the following steps: dissolving a to-be-detected sample in a buffer solution to obtain a sample buffer solution; incubating an electrochemical sensor electrode in the sample buffer solution to obtain an electrochemical sensor electrode incubated with a sample to be detected; a working electrode of the electrochemical sensor electrode is a gold electrode or an electrode with a gold coating; placing the electrochemical sensor electrode incubated by the sample to be detected in electrolyte, and performing electrochemical signal detection by using differential pulse voltammetry or cyclic square wave voltammetry; and analyzing the electrochemical signal. The detection method disclosed by the invention can be used for accurately detecting small-component ctDNA to achieve the effect of early screening of a generic cancer species, has a semi-quantitative characteristic, can be used for quantitatively analyzing a biological marker methylated ctDNA of a tumor, and can be used for reflecting the load change of the tumor by monitoring the concentration of the methylated ctDNA to realize the monitoring of the dynamic change of the tumor; and reference is provided for treatment effect and treatment scheme adjustment.

The invention provides a building decoration material environmental protection property detection and rating system. Relates to the technical field of building and decoration material detection, and comprises a multi-source detection unit which forms a composite detection channel through an electrochemical sensing coupling detection technology, and the composite detection channel detects key environmental protection indexes of building decoration materials to generate key environmental protection index data. According to the environment-friendly property detection and rating system for the building decoration material, the environment-friendly property of the building decoration material is comprehensively detected through a multi-source electrochemical detection technology in combination with methods such as infrared spectrum sensing, differential pulse voltammetry and electrochemical impedance spectroscopy. The innovative detection can evaluate the key environmental protection indexes of the material in multiple dimensions, such as formaldehyde emission, volatile organic compound concentration, heavy metal element content and radioactivity, so that the accuracy and comprehensiveness of the detection result are ensured, and the scientificity of environmental protection material evaluation is effectively improved.

The present invention discloses a hybrid enzyme cascade pseudo-enzyme modified electrode and a preparation method thereof and a detection method for organophosphorus pesticides, belonging to the field of detection and analysis technology, and solves the problems that the existing methods for detecting organophosphorus pesticide residues are high in cost, small in detection range, and few in detectable pesticide types. The present invention utilizes Burkholderia cepacia lipase to react with a metal salt solution to prepare a hybrid lipase Zn / hNF, and utilizes it to react with a chitosan solution to prepare a modified electrode AuNPs@Zn / hNF@Au; the present invention uses P‑NPP as a hydrolysis substrate, and uses the modified electrode AuNPs@Zn / hNF@Au to detect the electrical signal of the Zn / hNF hydrolysis product P‑NP by differential pulse voltammetry, and the inhibition rate of OPs on Zn / hNF is electrochemically analyzed to determine the concentration of the organophosphorus pesticide. The method of the present invention has the advantages of fast detection speed, wide detection range, low cost, high sensitivity, etc.

The invention relates to the technical field of electrochemical analysis and detection, and discloses a hyodeoxycholic acid detection method based on non-enzyme electrochemical sensing. According to the method, renewable beta-cyclodextrin (beta-CD) is taken as a matrix, an alkali metal potassium coordinated cyclodextrin metal organic framework material (K-CD-MOFs) is synthesized through an improved methanol gas phase diffusion method, and the alkali metal potassium coordinated cyclodextrin metal organic framework material (K-CD-MOFs) is loaded on a reduced graphene oxide (rGO) substrate; and the rGO-K-CD-MOFs nanocomposite material with high specific surface area, excellent hydrophilicity and biocompatibility is prepared. Neutral red is used as a redox probe, and the change of current in the system is detected through differential pulse voltammetry. Researches show that the detection performance is greatly optimized through the synergistic effect of rGO and K-CD-MOFs, the composite material has a wide linear detection range in the concentration range of 5.0-100.0 [mu] M, the sensitivity reaches 0.10 [mu] A.[ mu] M <-1 >, the detection limit (LOD, S / N = 3) is 1.97 [mu] M, and the composite material has excellent selectivity on hyodeoxycholic acid (HDCA).

According to the micro-plastic detection method, a glassy carbon electrode is used as a working electrode, a platinum wire electrode is used as a counter electrode, an Ag / AgCl electrode is used as a reference electrode, and potassium ferricyanide / potassium ferrocyanide is used as an electrochemical signal molecule; the method comprises the following steps: putting a three-electrode system into a KCl electrolyte solution which contains a microplastic and contains a potassium ferricyanide / potassium ferrocyanide probe, connecting the three-electrode system into an electrochemical workstation, then carrying out electric incubation on a solution system by using a cyclic voltammetry method, and detecting the concentration of the microplastic by using a differential pulse voltammetry method after incubation is finished. According to the invention, the electrochemical technology is innovatively used for micro-plastic detection. By utilizing the characteristic that micro-plastic is easily adsorbed on the surface of a glassy carbon electrode, an electric incubation method is adopted to enhance adsorption and reduce response of signal molecules, so that an electrochemical sensing detection method is established. The method has the advantages of rapidness, simplicity, low cost and the like, can be used for effectively detecting the micro-plastics in a wider range and keeping good sensitivity, and has a wide application prospect.

The invention belongs to the technical field of food analysis and detection, and particularly discloses a method for rapidly detecting tartaric acid in wine based on a molecularly imprinted polymer (MIP) modified carbon fiber electrode. According to the method, a tartaric acid molecularly imprinted polymer layer is constructed on the surface of a carbon fiber electrode by adopting an electrochemical polymerization technology, and high-sensitivity and high-selectivity detection of tartaric acid is realized in a potential range of-0.5 to + 0.6 V (vs.Ag / AgCl) in combination with a differential pulse voltammetry (DPV). The modified electrode has excellent conductivity and specific recognition capability, the detection limit is as low as 0.05 [mu] mol / L, and the linear range is 1-800 [mu] mol / L. The method is simple and convenient to operate, the single detection only needs 20 seconds, the relative standard deviation is less than 3.5%, the recovery rate reaches 95-102%, the method can be directly applied to stock solution detection of complex wine matrixes (such as dry red wine, dry white wine and sweet wine), complex pretreatment is not needed, and an efficient and reliable analysis means is provided for wine brewing process monitoring and quality evaluation.

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 invention discloses a method for detecting freshness of larimichthys crocea based on a Ti3C2Tx at CeO2 electrochemical sensor, which is characterized by comprising the following steps: placing the Ti3C2Tx at CeO2 electrochemical sensor in a to-be-detected larimichthys crocea sample solution, and testing peak current of a xanthine characteristic peak under 0.75 V and peak current of malondialdehyde characteristic peak under 0.95 V by adopting differential pulse voltammetry, according to the linear relation between the xanthine concentration and the peak current under 0.75 V and the linear relation between the malonaldehyde concentration and the peak current under 0.95 V, the concentration values of xanthine and malonaldehyde in the pseudosciaena crocea sample to be detected are calculated. The method has the advantages of strong synchronous detection capability, high sensitivity, low detection limit, simplicity, rapidness, strong specificity and high accuracy.

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.