89results about How to "Enables trace detection" patented technology

The invention relates to a silicon cantilever sensor, a preparation method and application thereof, and belongs to the field of micro-nano sensors. A porous silicon structure is formed in hydrofluoric acid solution nearby a free tail end of a cantilever through a selective anodic oxidation method. By using the increased specific surface structure of a porous silicon area, large amount of linear polymer or hyper-branched polymer sensitive molecules with silicon-oxygen head groups and specific tail groups for specificity identification are self-assembled on the inner wall of a silicon hole, and large amount of detected chemical molecules can be specifically captured to accumulate the capturing mass of larger detected substances. The silicon cantilever sensor has the advantages of simple structure, convenient manufacture and easy realization, and can be applied to trace chemical gas detection.

The invention relates to an electrochemical sensor based on a molecular engram and a preparation method and an application thereof. The electrochemical sensor based on the molecular engram comprises a working electrode, a reference electrode and a counter electrode, wherein the base electrode of the working electrode is a gold electrode; sulfonated graphene is modified on the surface of the gold electrode; after airing, polymerization is performed in an acid buffer solution containing o-phenylenediamine and dopamine till the oxidation peak current of the o-phenylenediamine falls to zero, and then dopamine is eluted in a sulfuric acid medium; and the reference electrode and the counter electrode are a saturated calomel electrode and a platinum wire electrode respectively. Under an optimal condition, a molecular engram sensor with molecule identifying performance is prepared by an appropriate eluting method, so that rapid analysis and detection of the dopamine are realized. The electrochemical sensor based on the molecular engram has the advantages of quick response, high selectivity, high sensitivity and the like on the molecular engram, the aim of identifying molecules is fulfilled, and detection of the dopamine in the presence of high-concentration ascorbic acid is realized.

A chemical preparation method for a CdTe quantum dot fluorescent probe for detecting a trace amount of paraquat comprises the step of modifying thioglycollic acid on the surface of the CdTe quantum dot fluorescent probe emitting a red emission spectrum band so as to enable the CdTe quantum dot fluorescent probe is provided with carboxyl functional groups on the surface. The preparation process comprises the following two specific steps: firstly, preparing a NaHTe solution; then, synthesizing CdTe quantum dots of which the surfaces are modified with thioglycollic acid, and adjusting the pH value to be 10-12 with KOH, so as to obtain the CdTe quantum dot fluorescent probe. According to the invention, carboxyl with negative charge on the surfaces of the CdTe quantum dots and target paraquat molecules with positive charge have the electrostatic interaction through the positive charge and negative charge, when the CdTe quantum dots and the paraquat approach to each other in space, the red spectrum band emitted by the CdTe quantum dot fluorescent probe can be absorbed by green target analyte paraquat modules through the fluorescence resonance energy transfer principle, and the detection of a trace amount of paraquat can be implemented through the utilization of the variation of the CdTe quantum dot fluorescence intensity.

The invention provides a method and system for testing the oil-gas-water profile of each section of a horizontal well by using environmental protection type tracers. The method comprises the steps that according to information containing the oil and gas reservoir type, the fracturing fluid type and the number of test sections, the kinds and the compositions of the chemical tracers are determined;the designed using quantity, the injection time and the injection velocity of the chemical tracer used at each section are determined; injection equipment of the tracers used for testing is determined, and the connecting process of equipment for completing on-site operation is determined and laid out before construction; injection operation of the corresponding chemical tracers required by construction sections is completed according to the designed pump injection procedure; after fracturing construction of the whole horizontal well is completed, continuous tracer test sampling operation is implemented according to the designed sampling time and frequency, and samples are tested in time after all sampling is completed; and a production profile map or a contribution ratio map of each layersection of the oil and gas reservoir horizontal well within the sampling period is drawn.

The invention relates to a sea cucumber-like nano composite material and a preparation method and application thereof. The sea cucumber-like nano composite material is in a core-shell structure and comprises a peptide nucleic acid-modified gold nanorod, a nano silver layer and gold nanoparticles. The preparation method of the sea cucumber-like nano composite material comprises taking the PNA-modified (peptide nucleic acid-modified) gold nanorod as the core, coating the surface of the gold nanorod with silver and growing the gold nanoparticles on the surface of the silver to obtain the sea cucumber-like core-shell structure. The sea cucumber-shaped nano composite material contains a large number of hot spots for plasma resonance which are distributed on the surface of the gold nanorod, thereby greatly improving the efficiency of Raman detection through the hot spots. The sea cucumber-shaped nano composite material is simple in synthesis and stable in properties and can be applied to high-sensitivity Raman detection.

The invention discloses a qualitative detection method for an illegal ingredient, i.e., Sudan red, in raw materials of feeds. According to the method, suspected areas are primarily screened through microscopic image processing, so a detection scope is reduced; then a microscopic Raman imaging spectrometer is used for detecting the Raman spectra of the suspected areas, the spectra are pretreated so as to obtain training samples, an IVISSA method sensitive to classes is used for waveband selection, and the IVISSA method can select characteristic peaks of Sudan red substantially different from characteristic peaks of other components, which enables detection efficiency and accuracy to be improved; the average spectrum of each training sample is taken and incorporated into a standard spectrum matching database; and the microscopic Raman spectrum of an unknown sample is acquired according to coordinates of detection points obtained in primary image election, then same spectral pretreatment is carried out, and a same wavelength variable is chose for one-to-one matching with each spectrum in the standard spectrum matching database according to a feature enhanced spectral angle matching method so as to determine whether the unknown sample contains Sudan red or not. The qualitative detection method has the advantages of rapid detection, good stability, and lower false positive rate and detection limits.

The invention provides a method for quantitatively detecting salbutamol by using CdTe quantum dots. The method comprises the following steps: uniformly mixing the CdTe quantum dots with surfaces modified by mercaptoacetic acid with a substance to be detected, namely salbutamol, in a phosphate buffer solution, and then detecting fluorescent strength of a system by adopting a molecular fluorometer to realize trace detection of salbutamol because that in a weakly alkaline solution system, the CdTe quantum dots with the surfaces modified with carboxyl groups having negative charges and target molecules having positive charges, namely salbutamol, form a new compound system through electrostatic interaction so as to cause fluorescence quenching. Detection results show that salbutamol has relatively high sensitivity and a relatively wide linear range against the fluorescence quenching of the CeTe quantum dots, so that the changes in the fluorescent strength of the CdTe quantum dots are used for realizing the quantitative detection of salbutamol; and furthermore, the method for quantitatively detecting salbutamol by using the CdTe quantum dots, provided by the invention, is very simple in experimental operation, the detection time is short and the analysis cost is low.

The invention relates to a method for detecting the content of phenylethanolamine A by utilizing a CdTe quantum dot. The method takes mercaptopropionic acid as a stabilizer; the CdTe quantum dot prepared by a microwave radiation heating method is used as a fluorescent probe; and the method for detecting the content of the phenylethanolamine A is established based on a fluorescent intensity enhancing effect on the CdTe quantum dot by the phenylethanolamine A. The method comprises the following steps: uniformly mixing the CdTe quantum dot with the phenylethanolamine A of a substance to be detected in a phosphate buffering solution; standing for 15 minutes; and detecting the fluorescent intensity of a system by adopting a molecular fluorescence photometer so as to realize trace detection of the phenylethanolamine A. The method has the advantages of high detection sensitivity, simplicity and convenience for operation, short detection time, low analysis cost, relatively low detection limit and relatively high standard recovery rate.

The invention provides a system and a method for monitoring the concentration of nitrogen pentoxide and nitric acid in atmosphere on line. The on-line monitoring system comprises an aerosol filtering unit, gas wet type absorbing and converting units and optical absorbing and detecting units, wherein the inlet end of the aerosol filtering unit is communicated with the atmosphere to be detected and is used for removing particulate matters from the gas; the outlet end of the aerosol filtering unit is divided into two paths which are connected with a first gas wet type absorbing and converting unit and a second gas wet type absorbing and converting unit and is used for absorbing nitrogen compounds in the gas by an acidic absorbing solution to form a nitrate solution and further converting into nitrite; the front end of the first gas wet type absorbing and converting unit is provided with a NO gas source and converts N2O5, which is introduced into the gas, into NO2; the rear ends of the two gas wet type absorbing and converting units are connected with a first optical absorbing and detecting unit and a second optical absorbing and detecting unit correspondingly to convert the nitrite into an ultraviolet-visible absorbent material and perform optical detection; the first optical absorbing and detecting unit obtains the nitric acid concentration of the N2O5-removed atmosphere; and the second optical absorbing and detecting unit obtains the sum of the nitric acid concentration and the N2O5 concentration of the atmosphere.

The invention discloses a dual-emission fluorescent probe and a method for simultaneously detecting nitrite ions and Hg<2+>, which belong to the technical field of environmental detection. The fluorescent probe is a compound formed by carbon quantum dots CQDs, Tb<3+> and 3-aminophenylboronic acid in a buffer solution system with the pH value of 7.0 to 8.0. The carbon quantum dots CQDs are preparedfrom a mixed aqueous solution of nicotinic acid and barbituric acid through a hydrothermal reaction. The detection method comprises the steps of quantitatively adding a to-be-detected solution into the buffer solution system for constant volume, and then scanning an emission spectrum of a fluorescence system in a wavelength range of 320 to 650nm by taking 260 to 280nm as an excitation wavelengthof the buffer solution after constant volume; and calculating the concentrations of Hg<2+> and NO2<-> in the to-be-detected solution according to the linear relationship between the fluorescence quenching efficiency at 373 nm and 545 nm and the concentration of a to-be-detected substance. The fluorescent probe provided by the invention not only can realize trace detection of NO2<-> and Hg<2+> in awater sample, but also has better consistency and selectivity in detection results compared with a spectrophotometric method.

The invention provides a fast sulfide ion test method. The method uses a property of ANS that the fluorescence of 4-Amino-1-Naphthalene sulfonate (ANS) can be effectively quenched by MnO2 nano-material to prepare the ANS / MnO2 composite system. When tiny portion of S<2-> is added in the system, because the oxidation-reduction reaction occurs between the S<2-> and MnO2 to generate divalent manganese ions in the solution, thus enhancing the fluorescence intensity of the ANS, and the increase of the fluorescence intensity is in a linear relationship with the S<2-> ions concentration, thus achieving the test of S<2-> ion. Compared with prior art the method has the advantages of being simple in operation and being able to test the S<2-> ion in a fast and real time mode.

The invention discloses a high-sensitivity food colorant detection method, which comprises the steps of dropping 10<-8>mol / L to 10<-3>mol / L of food colorant standard liquid on a flower-shaped nano silver particle SERS (Surface Enhanced Raman Scattering) substrate, and collecting a raman spectrogram and data of the food colorant standard liquid through a raman spectrometer; further adopting a principal component analysis method for processing the raman spectrum data of the food colorant standard liquid so as to obtain a raman spectrum intensity-food colorant concentration relational expression of the food colorant standard liquid; processing food to be detected into a solution, dropping the solution on the flower-shaped nano silver particle SERS substrate, collecting an SERS spectrogram and data of the food solution to be detected through the raman spectrometer, comparing with the SERS spectrogram of the food colorant standard liquid to obtain the attribute of a colorant in food to be detected, and obtaining the content of the colorant in the food to be detected through the SERS spectrum intensity-food colorant concentration relational expression of the food colorant standard liquid. The method can be used for detecting a trace colorant in the food, and is simple to operate.

The invention discloses a surface enhanced Raman scattering optical flow chip and a cleaning method thereof. The optical flow chip includes a substrate, a microfluidic channel which is arranged in thesubstrate and is used for accommodating a to-be-detected solution, an optical fiber which comprises an optical signal input end used for accessing an optical signal and an excitation end arranged inthe microfluidic channel, and a metal nano island substrate which is formed on the end surface of the excitation end and is used for generating surface plasma resonance under the excitation of external laser so as to adsorb substance molecules in the to-be-detected solution. The cleaning method comprises the following steps: introducing deionized water into the microfluidic channel, and enabling the deionized water to submerge the metal nano island substrate; and accessing an optical signal into the optical signal input end, closing the optical signal after a preset duration, and removing thedeionized water in the microfluidic channel. The chip is simple in structure, small in size, easy and convenient to manufacture, can detect low-concentration substances to be detected, can be rapidlycleaned and has improved reusability.

The invention discloses a method for determining the lead content of a feed mildew preventive. According to the method, wet digestion is conducted on the feed mildew preventive by using nitric acid, hydrochloric acid and hydrofluoric acid to obtain a digestion solution, hydroboron, potassium ferricyanide, sodium hydroxide and a lead stabilizer are prepared into a lead determination reagent, the digestion solution and the lead determination reagent are carried into a chemical atomizer for hydride generation, hydride is led to an atomic absorption spectrophotometer by using carrier gas to perform flame atomization, then the absorbance value of a lead element at the position of 283.3 nm wavelength is determined, and the lead content of the feed mildew preventive is obtained through calculation based on an established standard curve. The method enables the detection limit of the lead to reach the level ppb and can achieve trace detection, and the relative error of a parallel determination result is lower than 10%, the accuracy of the detection result is good, and the detection data is more real and reliable.

The invention relates to a composite fluorescent biosensor, and a preparation method and an application thereof. The composite fluorescent biosensor comprises a graphene quantum dot and a carboxymethyl cellulose-chitosan polyelectrolyte microsphere; and the carboxymethyl cellulose-chitosan polyelectrolyte microsphere is a microsphere having a core-shell structure, the core is made of melamine andformaldehyde, and the shell is made of chitosan and carboxymethyl cellulose. The preparation method of the organic-inorganic composite fluorescent biosensor and a fluorescence detection method of target biological polysaccharides are helpful for improving other biological sensors. The composite fluorescent biosensor formed by cellulose ether-based polyelectrolyte microsphere induced graphene quantum dot aggregation has a very good market prospect and very good industrial production values.

The invention belongs to the technical field of nano materials, and particularly relates to a nano composite material based on phosphorus-containing molybdenum polyoxometallate, a preparation method thereof, an aptamer sensor and an electrode of the aptamer sensor. The nano composite material comprises carbon, molybdenum disulfide nanosheets and silver-containing nanoparticles. The nano compositematerial is obtained by calcining silver-doped phosphorus-molybdenum polyoxometallate, and the silver-doped phosphorus-molybdenum polyoxometallate is obtained by reacting a silver source, phosphomolybdic acid and thioacetamide. The nano composite material has a relatively high specific surface area and relatively strong biological affinity; an electrochemical sensor constructed by the nano composite material has a relatively low detection limit when being used for detecting bisphenol A (BPA), and has high selectivity, good stability and reproducibility, excellent renewability and applicabilityin different environments.

The invention relates to a preparation method for an aptamer biosensor for T-2 toxin detection in food or feed and application, which belong to the technical field of electrochemical detection. The method is characterized by comprising steps: a gold nanorod (Au NRs) material is firstly synthesized and obtained; platinum is then reduced on the gold nanorods to form gold platinum nanorods (Au@PtNRs), through combination with reducing graphene oxide-tetraethylenepentamine (rGO-TEPA), increasing of an immobilization amount is realized, and the signal amplification ability is improved; then, through combination with single-stranded DNA signal probe, a biosignal probe is thus prepared; and finally, through fixing of molybdenum disulfide-polyaniline-chitin-gold nanoparticle composite material anda DNA capture probe, an aptamer biosensor for T-2 toxin detection is thus prepared. The sensor is successfully applied to trace detection of T-2 toxin in food or feed. The method has the advantages that the limitation of a T-2 toxin small molecule substance is broken through, and through introducing a nucleic acid aptamer, T-2 toxin high-sensitivity and high-specificity trace detection can be realized, and a simple and quick new strategy is provided for mycotoxin detection.

The invention discloses a preparation method for a monodisperse gold nanoparticle and an assembly thereof. The preparation method comprises the following steps of: firstly, preparing the monodisperse gold nanoparticle with a reflux method: mixing 82.4mg of HAuCl4.4H2O, 5.5ml of oleylamine with the mass concentration of 80% and 50ml of cyclohexane, stirring and introducing argon in for more than 30 minutes at the room temperature, then quickly raising temperature to 90DEG C, keeping for 10 hours at the temperature, gradually cooling to the room temperature, then, washing away solvent which does not react in the solution and byproducts in the reaction by ethanol, and carrying out centrifugation to obtain the gold nanoparticle; dispersing the obtained gold nanoparticle into 2ml of cyclohexane; and then, preparing a porous gold nanoparticle aggregate with an oil-water two-phase micro-emulsion method in a process of slowly volatilizing an organic phase. The preparation method has the advantages of simple technology, low cost, simple equipment and high sensitivity and can be applied to the preparation of other functional nanoparticle aggregates.

The invention discloses a method for measuring the dissolution amount of a PVA (Polyvinyl Alcohol) optical film, which comprises the following steps: soaking a PVA optical film to be measured in waterto prepare an extracting solution to be measured; taking a mixed solution of a boric acid solution and an iodine / potassium iodide solution as a chromogenic solution, adding the chromogenic solution into the to-be-detected extracting solution, then determining the absorbance, and obtaining the concentration of PVA in the to-be-detected extracting solution according to the standard relation curve of the absorbance and the concentration of PVA, thereby calculating the dissolution amount of the PVA optical film. According to the method, trace detection of PVA in the solution can be simply and efficiently realized, the dissolution amount of the PVA optical film can be quickly measured, and the method has guiding significance for evaluating the product quality of the PVA optical film.

The invention relates to a super-hydrophobic surface reinforced Raman substrate prepared from a silicon nanometer dielectric material and a preparation method thereof. The substrate is formed by a silicon micron cone integrated with metal nanoparticles and a cascade structure formed by nanowires. The preparation method of the structure comprises the following steps that S1, a silicon wafer is put into a micromolecule alcohol and strong base mixed solution; the silicon micron cone structure is built through water bath heating; S2, the silicon micron cone structure is put into mixed corrosion liquid of silver salt solution and HF solution; etching is performed to obtain a silicon micron / nanometer cascade structure; S3, the silicon micron / nanometer cascade structure obtained in the S2 is soaked by acid solution so as to remove silver nanoparticles remained at the surface; then, the silicon micron / nanometer cascade structure is subjected to gold nanoparticle wrapping covering; S4, low-surface-energy substances are used for performing surface covering modification on the gold-silicon composite structure obtained in the S3, i.e., the super-hydrophobic surface reinforced Raman substrate is obtained. The super-hydrophobic surface reinforced Raman substrate provided by the invention has super-hydrophobic property; the static contact angle with water is 160 to 162 degrees.

The invention discloses a sulfide ion detection method based on a Ce(III) / AgNCs composite nano cluster material. Ce(III) ions can effectively enhance fluorescence emission of AgNCs, so as to form a Ce(III) / AgNCs composite system. When a trace of S<2-> is added to the system, S<2-> reacts with Ag atoms in the Ce(III) / AgNCs composite system, consequently, an original structure of the Ce(III) / AgNCs composite system is damaged, then the fluorescence strength of the Ce(III) / AgNCs composite system is eliminated, the eliminated fluorescence strength and concentration of S<2-> ions are in a linear relationship, so that the S<2-> ion detection method is created. The method is easy to operate, and can detect a trace of S<2-> rapidly in real time.

The invention relates to a synthesis method and application of disalicylaldehyde condensation 2-pyridine formylhydrazine schiff base, and relates to a synthesis method and application of 5,5'-methylethylidene disalicylaldehyde condensation 2-pyridylformylhydrazine schiff base. The method constructs a novel disalicylaldehyde condensation 2-pyridine formylhydrazine schiff base fluorescent probe which is applied to aluminum ion detection. The preparation method comprises dripping a disalicylaldehyde solution into a 2-pyridine formylhydrazine solution, heating and refluxing to separate out a solid, cooling, filtering by suction, and washing to obtain the fluorescent probe. The detection limit of the probe for aluminum ions in a DMF solution is 6.21* 10<-8> mol / L, the fluorescence intensity isenhanced by 302 times, and the complexing ratio of probe molecules to aluminum ions is 1: 2. The probe has good selectivity and anti-interference performance, and can be widely applied to the analysisand detection of aluminum ions in industries such as environment, food, medicine and the like.

The invention discloses a water body polycyclic aromatic hydrocarbon detection reagent. The detection reagent consists of a reagent A and a reagent B, wherein the reagent A is an aqueous solution of a graphene / nano precious metal compound, and the reagent B is a surfactant solution. The invention also discloses an application of the water body polycyclic aromatic hydrocarbon detection reagent. The application comprises the steps of: firstly dispersing the reagent B in a polycyclic aromatic hydrocarbon solution; then adding the reagent A into the mixed solution and evenly mixing; and finally performing Raman detection on a suitable amount of the mixed solution to obtain a polycyclic aromatic hydrocarbon SERS (Surface Enhanced Raman Scattering) spectrum. The invention provides the water body polycyclic aromatic hydrocarbon detection reagent and the application thereof which can be used for rapidly detecting polycyclic aromatic hydrocarbons in a water body, are convenient to detect and good in data repeatability, and can realize the single-component or multi-component detection of the polycyclic aromatic hydrocarbons.

The invention relates to a method for testing the trace of a nanogold particle with a specific particle diameter. The method comprises the steps as follows: an antigen of the nanogold particle with the specific particle diameter is prepared; the antigen is injected into an animal; a high specific antibody is prepared; the content of the nanogold particle with the specific particle diameter is measured by adopting an absorbance method; an abzyme is marked to prepare an enzyme label double antibody; by adopting an indirect competitive enzyme-linked immunifaction, a standard sample competes against a sample to be tested to react with the antibody; an enzyme of the enzymbe label double antibody enables a substrate solution to emit light; the value of absorbancy is measured; the density of the sample to be tested is obtained via a standard curve. According to the method, the specificity of the antibody of the nano-gold particle with the specific particle diameter is high, and cross reactions are less, so that the selectivity is high, and further the pretreatment process of the sample is simplified.

The invention discloses an on-line measuring system and a measuring method for concentration of nitrous acid and nitrous acid. The system comprises an external sample feeding unit, a liquid phase chemical conversion unit and an optical absorption detection unit which are connected in sequence, wherein the external sample feeding unit is used for feeding a sample of a nitrogen-containing compound; the liquid phase chemical conversion unit is used for absorbing and converting the liquid phase chemical conversion unit from the external sample feeding unit into nitrite; and the optical absorption detection unit is used for converting the nitrite from the liquid phase chemical conversion unit into an ultraviolet-visible absorbent material, and used for implementing optical detection. By adopting the system, simultaneous measurement of the nitrous acid and the nitric acid can be achieved, and furthermore interference of other gaseous phase substances can be eliminated through parallel channels. By adopting the system, trace detection on the nitrous acid and the nitric acid in the atmosphere can be achieved, and trace detection on the nitrous acid and the nitric acid in water bodies is also achieved, the detection sensitivity is greater than 10pptv and 0.03mu g / L, the response time is less than 3-5 minutes, and the system can be applied to atmospheric environments, water body environment monitoring, experimental scientific research and the like.

The invention discloses a heparin detection method for a copper nano-cluster based on a denatured bovine serum protein as template. The method comprises the following steps: forming a heparin detection system with a phosphoric acid buffer aqueous solution, a copper nano-cluster dispersion system and a to-be-tested sample; detecting fluorescence intensity change before and after adding the to-be-tested sample; and comparing with a standard curve to obtain the content of heparin in the to-be-tested sample. The method synthesizes the copper nano-cluster by taking the denatured bovine serum protein as the template by means of a one-pot method. The synthesized material is uniform in particle size, good in fluorescence property and stable in property, and the light-emitting position is near 642.04 nm and belongs to a near infrared area, so that interference of autofluorescence is avoided. The method can detect the heparin content directly and quickly, is wide in detection linear range and low in detection limit and has a very good application prospect in the fields of biological system detection, clinical applications and the like.

The invention provides a preparation method and an application of a fluorescence sensor for detecting ochratoxin A. A quantum dot-nano porphyrin fluorescence 'on-off' sensor is formed with a water-soluble ZnCdSe quantum dot as a fluorescent probe and self-assembled nano porphyrin, which is prepared from a tetra-(4-pyridyl)-zincporphyrin-N,N-dimethylformamide solution and dodecyl dimethyl betaine,as a quantum dot fluorescence quencher. The OTA is combined with nano porphyrin to release quantum dots, so that the fluorescence of the quantum dots is recovered, and the quantum dot-nano porphyrin fluorescence "on-off-on" sensor is formed. The addition of other mycotoxins does not cause the change of the fluorescence intensity of the system. The fluorescence sensor realizes high-selectivity detection of OTA, effectively amplifies signals, obtains high-sensitivity and strong-specificity detection results, does not need to depend on expensive large instruments, and is simple in pretreatment and rapid in detection.

The invention relates to a method for detecting aflatoxin M1. According to the method, aflatoxin B1 marked by enzyme is taken as a competitive antigen, and on the basis of a dynamic light scattering technology, the aflatoxin M1 is detected through a direct competitive enzyme linked immunoassay analysis method. The method reduces the affinity between the competitive antigen and a monoclonal antibody of the aflatoxin M1, and the problem is solved that the sensitivity is reduced due to the fact that the competitive antigen is not easily competed by s target competitive antigen; the detection of an output signal is performed by means of the dynamic light scattering method, compared with a traditional direct competitive enzyme linked immunoassay analysis method, the detection sensitivity can beimproved, and the trace detection of the aflatoxin M1 can be achieved.

The invention relates to a Cu3P-coated Ti-MOF-NH2 composite material, an electrochemical sensor and a preparation method and an application thereof. The preparation method comprises the following steps: 2-aminoterephthalic acid, tetrabutyl titanate, and Cu3P are subjected to a solvent heat reaction in a solvent to obtain the product. The Cu3P and Ti-MOF-NH2 has strong synergism, effective charge separating and transfer on a catalyst interface can be promoted, and electro-catalysis oxidation effect of hydrazine hydrate is promoted. The electrochemistry test shows that the Cu3P-coated Ti-MOF-NH2composite material has protruded electrocatalytic activity on the oxidation of the hydrazine hydrate, has high sensitivity and selectivity on the hydrazine hydrate detection by an electrode producedby the composite material, and has large application prospect in the field of electrochemical analysis.

The invention discloses an electrochemical sensor electrode surface nano-material modification method and a sensor. Carbon paper is used as a working electrode substrate; graphene nano, thionine and nano gold are modified on the surface of a working electrode to form a composite biosensitive membrane; and a specific antibody is fixed to the biosensitive membrane, and antigen detection is realizedby utilizing that the antigen concentration is proportional to the reduction degree of the reaction current. The multilayer nano sensitive membrane sensor can realize trace detection of high-sensitivity cancer protein and polypeptide molecules.