127 results about "Tetramethyl benzidine" patented technology

The invention discloses a fluorescent colorimetric sensor for detecting circulating tumor cells and a preparation method of the fluorescent colorimetric sensor. The preparation method comprises the following steps: S4, adding a prepared detection antibody modified with horse radish peroxidase and used for detecting the circulating tumor cells, and incubating; s5, adding a Tris buffer solution and a H2O2 solution, and incubating; s6, preparing an EuMOF nanoflower solution; and S7, adding the EuMOF nanoflower solution and 3, 3 ', 5, 5'-tetramethyl benzidine to react, detecting the fluorescence intensity in the presence of circulating tumor cells with different concentrations by using a luminoscope, detecting the ultraviolet absorbance value in the presence of circulating tumor cells with different concentrations by using a multifunctional microplate reader, and constructing a fluorescence intensity-concentration working curve and an ultraviolet absorbance value-concentration working curve. The method is used for qualitative and quantitative analysis and detection of the circulating tumor cells, realizes bimodal signal response to the circulating tumor cells, and has high sensitivity and simplicity and convenience in operation.

The invention discloses a method for constructing a dual-mode sensor through smartphone-assisted surface molecular imprinting for detecting diphenyl phosphate and application of the dual-mode sensor, and belongs to the technical fields of biochemical analysis, functional nano materials and life science. In synthesis, solubility and selectivity of a target object and photo-initiation efficiency in a polymerization process are optimized, and diphenyl phosphate molecularly imprinted nano-enzyme MIPs is rapidly prepared through a molecular imprinting technology; in the detection, H2O2 and 3, 3, 5, 5-tetramethyl benzidine TMB are catalyzed by peroxidase-like activity of Fe and N-CDs to generate a chromogenic reaction and an inner filter effect of oxTMB is used for inhibiting a fluorescence signal, dual-signal cross validation is realized in cooperation with a smart phone, and the colorimetric-fluorescence sensor for detecting diphenyl phosphate is constructed. The sensor has specific recognition selectivity and binding affinity of diphenyl phosphate, is simple to operate and low in cost, can realize sensitive detection of diphenyl phosphate in a wide linear range, has the detection limit as low as 16 pg / mL, and is suitable for field analysis of trace DPhP in a complex water environment.

The invention discloses a preparation method of a carbon dot nano-enzyme, which comprises the following steps: dissolving oxalic acid, polyethyleneimine and ferric nitrate in ultrapure water, heating, mixing and reacting, cooling to room temperature, centrifuging, filtering, dialyzing, and taking supernate to obtain the carbon dot nano-enzyme. The prepared oxalic acid carbon dot nano-enzyme is matched with acetylcholin esterase, acetylcholine, 3, 3 ', 5, 5'-tetramethyl benzidine and H2O2 to construct a colorimetric and fluorescent dual-mode detection method for glyphosate in fruits and vegetables. The oxalic acid carbon dot nano-enzyme is prepared by doping ferric nitrate and tetraethylenepentamine into oxalic acid serving as a precursor, the oxalic acid carbon dot nano-enzyme has excellent peroxidase-like activity, a colorimetric and fluorescent dual-mode detection method of glyphosate is constructed through the oxalic acid carbon dot nano-enzyme, dual-mode detection results can be mutually verified, and the detection result is accurate. And the accuracy and the reliability of a detection result are remarkably improved.

A formula of the reinforced and toughened carbon nanotube modified polypropylene resin comprises a carbon nanotube filler, hexadecyl trimethyl ammonium bromide, chopped glass fibers, polyvinylpyrrolidone, gamma-aminopropyltriethoxysilane, an ethylene-octylene copolymer, 3, 3 ', 5, 6-tetramethyl-3, 5, 6-tetramethyl-3, 5, 6-tetramethyl-3, 5, 6-tetramethyl-3, 5, 6-tetramethyl-3, 5, 6-tetramethyl-3, 5, 6-tetramethyl-3, 6-tetramethyl-3, 5, 6-tetramethyl-3, 6-tetramethyl-3, 6-tetramethyl-3, the invention discloses a polypropylene composite material, which is composed of a carbon nanotube filler, a polypropylene matrix, 2, 3 ', 5, 5'-tetramethyl benzidine and maleic anhydride grafted polypropylene, the carbon nanotube filler is subjected to surface modification by hexadecyl trimethyl ammonium bromide to form a carbon nanotube reinforcement with a surface hydrophilic layer, and chopped glass fibers are arranged in an oriented manner in an extrusion direction in a melt blending process to synergistically enhance the mechanical strength of the polypropylene matrix; the ethylene-octylene copolymer is subjected to melt blending to form toughening particles, 3, 3 ', 5, 5'-tetramethyl benzidine induces a polypropylene matrix to form rod-like long-grain beta crystals, and high toughness of the matrix is achieved synergistically; the synthesized polypropylene matrix can be used for preparing a fiber composite material. The fiber composite material prepared by the invention has excellent mechanical strength, and the toughness and impact resistance are remarkably improved.

The invention belongs to the technical field of sensors, and relates to an array sensor based on cerium-based metal organic framework nano-enzyme and detection application of perfluoroalkyl compounds. The array sensor is a Ce-MOF triple enzyme activity array sensor and is provided with a plurality of mutually independent sensing channels; the sensing channel contains a Ce-MOF nano enzyme and a chromogenic substrate; the chromogenic substrates comprise a first chromogenic substrate, a second chromogenic substrate and a third chromogenic substrate, the first chromogenic substrate comprises 3, 3 ', 5, 5'-tetramethyl benzidine, the second chromogenic substrate comprises 2, 4-diaminophenol and 4-aminoantipyrine, and the third chromogenic substrate comprises xanthine, purine oxidase and nitrogen blue tetrazole. The MOF nano-enzyme array sensor constructed by the invention has relatively high sensitivity and selectivity in identification and distinguishing of PFASs compounds, not only can accurately distinguish single PFASs compounds, but also can perform quantitative detection, and has good response to PFASs with different concentrations.

The invention discloses a method for detecting glucose on the basis of cascade catalysis of cerium dioxide / gold nano cluster-Prussian blue nano enzyme (AuNCs-CeO-HMPB). The material is prepared by compounding cerium dioxide (CeO) with similar glucose oxidase activity and hollow Prussian blue nanoparticles (AuNCs-HMPB) modified by gold nanoclusters with similar peroxidase activity through a hydrothermal assembly method. In the presence of glucose, CeO catalyzes oxidation of glucose to generate gluconic acid and H2O2, then AuNCs-HMPB synergistically catalyzes decomposition of newly generated H2O2 to generate high active oxygen species, further a colorless 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) color developing agent is oxidized to generate obvious color change, and based on the cascade catalytic reaction, the enzyme-free glucose colorimetric sensor is successfully constructed. The sensor shows excellent detection performance on glucose under optimized conditions (pH = 4.0, 50 DEG C), the linear detection range is 10.00-90.00 [mu] mol / L, and the detection limit is 2.1 [mu] mol / L (S / N = 3).

The invention belongs to the technical field of colorimetric chemical sensors, and particularly relates to a preparation and application method of a smartphone-assisted surface molecular imprinting colorimetric sensor for detecting norfloxacin, magnetic Fe3O4 (at) KH540 nanoparticles are taken as a matrix, magnetic norfloxacin surface molecular imprinting nano-enzyme MMIPs is prepared by adopting a surface molecular imprinting technology, then the MMIPs, H2O2 and 3, 3 ', 5, 6, 7-tetramethyl-3, 5, 6-tetramethyl-3, 5, 6-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3-tetramethyl-3 The colorimetric sensor for detecting norfloxacin is constructed by carrying out a chromogenic reaction on 3, 3 ', 5, 5'-tetramethyl benzidine TMB and cooperating with a smartphone. The sensor has specific recognition selectivity and binding affinity for NOR, is simple to operate, high in detection speed and low in cost, does not need expensive instruments, and can be suitable for field analysis.

The invention discloses a kit for detecting transferrin and application of the kit, and belongs to the technical field of transferrin content detection. The kit comprises a PBA-SiO2 (at) Fe3O4 magnetic affinity probe and an Ab-Au, Pt, Cu (at) PDA nano enzyme immune probe, and when the transferrin exists, the PBA-SiO2 (at) Fe3O4 magnetic affinity probe and the Ab-Au, Pt, Cu (at) PDA nano enzyme immune probe are combined with the transferrin to form a sandwich structure similar to a sandwich. A substrate generates an oxidation product 3, 3 ', 5, 5'-tetramethyl benzidine diimine with color development capability by utilizing the catalytic performance of Ab-Au, Pt, Cu (at) PDA nano-enzyme and the Raman enhanced activity of Au, Pt and Cu metals, and a novel transferrin multi-mode sensing platform which is rapid, sensitive, high in selectivity and high in reliability is established; and in combination with visual sensing analysis, the transferrin in a sample can be rapidly and semi-quantitatively detected on site. The method is expected to be applied to on-site rapid detection of low-concentration transferrin in samples such as sweat, blood and urine.

The invention relates to a diatomic catalyst for detecting carbosulfan pesticide residue and a preparation method, and belongs to the technical field of food safety detection. According to the invention, a reducing sulfide generated by breaking a nitrogen-sulfur (N-S) bond of carbosulfan under an acidic condition is used as a specific substance. The reductive sulfide not only can prevent bimetal active sites in the diatomic catalyst, but also consumes hydroxyl radicals generated by catalyzing hydrogen peroxide (H2O2), and the sensing switch enzyme formed by a dual enzyme inhibition mechanism causes the enzyme substrate 3, 4-dihydroxyl-3, 4-dione to be converted into the diatomic catalyst, so that the catalytic activity of the diatomic catalyst is improved. The blue color of the 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) gradually becomes light along with the increase of the concentration of carbosulfan, sensitive visual detection is implemented, and after a blue product is read by using an ultraviolet spectrophotometer, the absorbance value generated by an ultraviolet absorption spectrum at 654 nm is linearly dependent on carbosulfan. The prepared diatomic catalyst effectively improves the detection sensitivity of the carbosulfan pesticide residue, and has good popularization and application prospects.

The invention discloses a method for detecting aflatoxin B1 in coffee based on colorimetric and photo-thermal dual modes of MXene (at) Pt nano-enzyme, which comprises the following steps: etching Ti3AlC2 by using LiF and HCl to obtain MXene, synthesizing platinum nano-particle modified MXene nano-enzyme (MXene (at) Pt) by using dopamine carbon dots and sodium borohydride as reducing agents and adopting an in-situ reduction technology, and detecting aflatoxin B1 in coffee by using the MXene (at) Pt nano-enzyme (MXene (at) Pt nano-enzyme (MXene (at) Pt nano-enzyme (MXene (at) Pt nano-enzyme (MXene (at) Pt). The MXene (at) Pt shows near-infrared light stimulation enhanced peroxidase-like activity and photo-thermal performance and can catalyze blue deepening and temperature rising of a substrate 3, 3 ', 5, 5'-tetramethyl benzidine (TMB), when aflatoxin B1 exists, POD-like activity of MXene (at) Pt nano-enzyme is inhibited, and colorimetric and temperature signals are reduced; a method for detecting the AFB1 by the colorimetric temperature dual-mode sensor is established, and the method has the characteristics of high sensitivity, strong specificity, simplicity and rapidness in operation and the like.

The invention provides high-permeability colorimetric hydrogel for detecting the content of glucose in sweat and a preparation method of the high-permeability colorimetric hydrogel, and relates to the technical field of wearable colorimetric sensing. The preparation method of the high-permeability colorimetric hydrogel comprises the following steps: mixing polyoxyethylene polyoxypropylene ether, chloroplatinic acid, chloroauric acid and water, and then adding L-ascorbic acid for reaction to obtain gold-platinum nanocrystalline dendrites; the preparation method comprises the following steps: mixing polyvinyl alcohol, 3, 3 ', 5, 5'-tetramethyl benzidine, gold-platinum nanocrystalline dendrites, ethylene glycol and water to obtain a hydrogel precursor solution, and curing the hydrogel precursor solution to obtain a hydrogel precursor; and soaking the hydrogel precursor in a sodium chloride solution to obtain the high-permeability colorimetric hydrogel for detecting the content of glucose in sweat. The gold-platinum nanocrystal dendrite nanoenzyme has tandem bio-enzyme activity, glucose oxidase activity and peroxidase double-enzyme activity, and TMB is used as a chromogenic substrate to prepare the hydrogel, so that colorimetric detection of glucose can be realized.

The application discloses a machine learning enhanced silver-based covalent organic framework nanoscale enzyme colorimetric detection method and application thereof, and constructs a covalent organic framework loaded with silver nanoparticles to form a nanoscale enzyme with oxidase-like activity, which is used for rapid visual detection of mercury ions. When mercury ions exist, silver ions in the COF-AgNPs can form silver amalgam with the mercury ions, thereby catalyzing the colorless substrate 3,3',5,5'-tetramethylbenzidine to generate a blue oxidation product oxTMB. The content of mercury can be judged by detecting the absorbance and RGB value changes of the color development reaction. Meanwhile, a machine learning data analysis strategy of a support vector machine model is adopted to perform five-fold stratified cross-validation analysis on the obtained absorbance and RGB values, so that the detection range is expanded and the detection sensitivity is improved.

The invention discloses a nano-enzyme-SERS (Surface Enhanced Raman Scattering) bifunctional sensor for detecting colorectal cancer markers with high sensitivity as well as a preparation method and application of the nano-enzyme-SERS bifunctional sensor. The preparation method comprises the following steps: coating a layer of platinum (Pt) on the surface of gold nanoparticles (AuNPs) by utilizing a chemical reduction method so as to form gold-platinum nanoparticles (Au (at) Pt NPs); assembling the synthesized Au (at) Pt NPs into an aminated capillary tube through electrostatic adsorption, so as to prepare a capillary tube SERS (Surface Enhanced Raman Scattering) substrate; the surface of Au (at) Pt NPs is modified with a marker aptamer through an Au-S bond, and the nano enzyme-SERS dual-function sensor is prepared. In the presence of hydrogen peroxide (H2O2), the Au (at) Pt NPs can catalyze the oxidation of 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) to generate oxidized TMB (oxTMB) with a strong SERS (Surface Enhanced Raman Scattering) signal. When Hcy exists, the reductive sulfydryl of Hcy consumes hydroxyl free radicals (. OH) generated by H2O2 decomposition, so that TMB oxidation is inhibited, and SERS signal intensity is weakened. A linear regression equation of the logarithm of the Hcy concentration and the signal intensity is drawn according to the SERS signal intensity, so that quantitative detection of the Hcy is realized.

The invention provides an ascorbic acid high-sensitivity colorimetric sensor as well as a preparation method and application thereof, and aims to solve the problem of low sensitivity of an MOFs (Metal-Organic Frameworks) nano material in ascorbic acid detection. Ce-UiO-66-NH2 nano enzyme particles can catalyze O2 to oxidize TMB (Tetramethylbenzidine) to generate a blue product (TMBOX) under an acidic condition; based on the principle that the absorbance of a mixed solution is reduced due to the fact that the ascorbic acid can react with TMBOX, the high-sensitivity ascorbic acid colorimetric sensor composed of Ce-UiO-66-NH2 nano-enzyme particles with the diameter of 10-50 nm and a chromogenic substrate 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) is constructed. Compared with MnO2, Pt-BGP NCs, CeO2 (at) PTA HNS and Co-PB NCs, the prepared ascorbic acid high-sensitivity colorimetric sensor has the advantages that the reaction time is shorter, and the content of ascorbic acid can be rapidly measured within 15 seconds. Based on the principle, the invention further provides a portable colorimetric test paper for visually detecting the ascorbic acid, and the ascorbic acid in the liquid lemon water can be semi-quantitatively detected by naked eyes within 30 seconds.

The invention discloses a machine learning enhanced silver-based covalent organic framework nano-enzyme colorimetric detection method and application thereof, and constructs a nano-enzyme which is formed by loading silver nanoparticles on a covalent organic framework and has oxide-like enzyme activity, and the nano-enzyme is used for rapid visual detection of mercury ions. When mercury ions exist, silver ions in the COF-AgNPs can form silver amalgam with the mercury ions, so that a colorless substrate 3, 3 ', 5, 5'-tetramethyl benzidine is catalyzed to generate a blue oxidation product oxTMB. And the mercury content can be judged by detecting the absorbance and RGB value change of the chromogenic reaction. And meanwhile, a machine learning data analysis strategy of a support vector machine model is adopted to carry out five-fold layered cross validation analysis on the obtained absorbance value and RGB value, so that the detection range is expanded, and the detection sensitivity is improved.

The invention belongs to the technical field of tin ion detection, and provides a method for detecting tin ions based on Ce-UiO-66-NO2 nano enzyme. The method comprises the following steps: mixing Ce-UiO-66-NO2 nano-enzyme with colorless 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) to generate blue oxidation-state TMB, then adding a sample containing tin ions (Sn < 2 + >), and reducing the oxidation-state TMB by utilizing the strong reducibility of the tin ions (Sn < 2 + >), so that the color of the solution becomes light; the tin ions (Sn < 2 + >) are qualitatively detected according to color change, or the tin ions (Sn < 2 + >) are quantitatively detected by utilizing a linear relation between the change of the absorbance value of the solution before and after the tin ions (Sn < 2 + >) are added and the concentration of the tin ions (Sn < 2 + >). The method has the advantages of low detection limit, high selectivity and good stability, and realizes the purpose of rapid detection of tin ions in tap water.

The invention belongs to the field of biosensor detection, and particularly discloses a colorimetric detection method based on functionalized copper cysteine nano-enzyme, which comprises the following steps: preparing a specific functionalized copper cysteine nano-enzyme composite material; and constructing a detection reaction system containing hydrogen peroxide, tetramethyl benzidine, an acetate buffer solution and a target solution, and determining the concentration of the target by using a colorimetric analysis technology. Particularly, CuCl2. 2H2O is used as a copper source, PEG-4000 is used as polyethylene glycol, reaction is performed under nitrogen protection and alkalescence conditions, and then the reaction product reacts with chloroauric acid and trisodium citrate to prepare the composite material. According to the method, hydrogen peroxide and tetramethyl benzidine are taken as substrates, high-sensitivity detection of a target object (such as dopamine) is realized by measuring an absorption peak value of a reaction system at 652nm, and a standard curve is drawn so as to accurately measure the concentration of a solution to be measured. The method is simple and convenient to operate and high in sensitivity, and has a wide application prospect in detection of biological molecules such as dopamine.

The invention relates to a preparation method and application of a cascade reactor based on 2D MOF. According to the method, a regular layered MOFs material is prepared by adjusting the molar ratio and concentration of different metal salts to ligands, then the material is soaked in an ethanol and isopropanol solvent, the material is activated through ultrasonic waves in an ice-water bath, layered separation is achieved through intermolecular force, a 2D MOFs material with the micron-scale size and the nano-scale thickness is obtained, finally, SOX is added, and the 2D MOFs material with the micron-scale size and the nano-scale thickness is obtained. The method comprises the following steps: carrying out a two-dimensional (2D) MOF / SOX cascade reactor to obtain a two-dimensional (2D) MOF / SOX cascade reactor capable of constructing a colorimetric sensor with TMB (3, 3 ', 5, 5'-tetramethyl benzidine). The reactor can perform 1-400 [mu] M linear quantification on sarcosine, and LOD is 0.324 [mu] M. According to the invention, high-efficiency, simple and cheap Pca capable of being rapidly detected can be synthesized without complex synthesis processes, instruments and expensive precious metals.

The invention relates to the technical field of analytical chemistry and food pharmacy detection, in particular to a rutin antioxidant activity colorimetric determination method based on a composite nano enzyme, which comprises the following steps: mixing a to-be-detected sample solution with an ABTS free radical cation working solution to carry out first reaction, so that an antioxidant substance in a sample and ABTS free radical cations are subjected to scavenging reaction; adding the composite nano enzyme, a 3, 3 ', 5, 5'-tetramethyl benzidine solution and a hydrogen peroxide solution into a system after the first reaction is completed, and initiating a second reaction; and measuring the absorbance value of the system after the second reaction under a specific wavelength, comparing the absorbance value with the standard curve obtained through the treatment in the same step, and calculating the antioxidant activity expressed by the equivalent concentration of rutin in the sample to be detected. By optimizing reaction conditions, the method provided by the invention simplifies operation steps and can provide accurate measurement results in a wider concentration range.

The invention provides a high-entropy nano enzyme. The chemical formula of the high-entropy nano enzyme is Mn < 0.4 > Co < 0.4 > Ni < 0.4 > Cu < 0.4 > Zn < 0.4 > Fe < 2.0 >) O. The invention also provides a preparation method of the high-entropy nano-enzyme, which comprises the following steps: dissolving manganese nitrate tetrahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, copper nitrate trihydrate, zinc nitrate hexahydrate and sodium citrate in deionized water to prepare a clear solution A; dissolving potassium ferricyanide in deionized water to prepare a clear solution B; directly pouring the solution B into the solution A, stirring, standing and aging the obtained mixed solution at room temperature, and centrifugally collecting a product; and calcining the sample powder in a muffle furnace to obtain the high-entropy nano-enzyme. The invention further provides a catalyst which is composed of the high-entropy nano enzyme, 3, 3 ', 5, 5'-tetramethyl benzidine and H2O2. The invention also provides a method for detecting reduced glutathione by using the microfluidic paper chip analysis device. The invention provides a new normal form for constructing a multifunctional biosensing and environment monitoring platform.

The application discloses a preparation method of carbon dot nanometer enzyme, which comprises the following steps: dissolving oxalic acid, polyacetyl imine and ferric nitrate in ultrapure water, heating and mixing, cooling to room temperature, centrifuging, filtering, dialyzing and taking supernatant to obtain the carbon dot nanometer enzyme; and a double-mode detection method for colorimetric and fluorescent detection of glyphosate in fruits and vegetables is constructed by using the prepared oxalic acid carbon dot nanometer enzyme, acetylcholinesterase, acetylcholine, 3,3',5,5'-tetramethyl benzidine and H2O2. The oxalic acid carbon dot nanometer enzyme is prepared by doping ferric nitrate and tetraethylenepentamine with oxalic acid as a precursor, has excellent peroxidase-like activity, and a colorimetric and fluorescent double-mode detection method for glyphosate is constructed by using the oxalic acid carbon dot nanometer enzyme, the double-mode detection results can be verified with each other, and the accuracy and reliability of the detection results are significantly improved.

The present invention discloses the use of a copper-iron bimetallic oxide in the colorimetric detection of hexavalent chromium. The present invention utilizes a coprecipitation method to synthesize the copper-iron bimetallic oxide in a single step. This inexpensive and readily available copper-iron bimetallic oxide can highly selectively catalyze the Cr(VI) and 3,3',5,5'-tetramethylbenzidine (TMB) system to produce a visual blue color. Within a certain concentration range, the depth of the blue color is proportional to the Cr(VI) concentration, thus establishing a new colorimetric method for the detection of Cr(VI). In this system, the linear range for Cr(VI) detection is 0.3 μmol / L to 26 μmol / L, with a detection limit of 0.17 μmol / L. The system can be used for the detection and analysis of Cr(VI) in the environment and food.

The invention discloses a lactate oxidase portable mobile phone sensing method based on a composite MXene thin-layer material and an application of the lactate oxidase portable mobile phone sensing method. Firstly, a Cu0. 9Zn0. 1S (at) MXene thin-layer material is synthesized and can catalyze H2O2 into hydroxyl free radicals, the generated hydroxyl free radicals react with a colorless 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) solution to generate blue oxidation-state 3, 3 ', 5, 5'-tetramethyl benzidine (oxTMB), the oxTMB can have an obvious ultraviolet absorption peak at 652nm, and a novel visual analysis method is constructed by taking the peak as signal output; besides, lactate oxidase can catalyze lactic acid to generate pyruvic acid and H2O2, a new method is used for LA or LOX analysis by taking H2O2 as a relation, H2O2 generated by the reaction can participate in the oxidation reaction of TMB, an obvious ultraviolet absorption peak can appear at 652nm, and the inhibitor Fe (III) can inhibit the reaction. On the basis, a portable mobile phone sensing method which is rapid, simple and low in cost is constructed, and the method is successfully applied to sensitive detection of LOX in HEK293S cells and has scientific significance.

This invention discloses a method and application for constructing a dual-mode sensor for detecting diphenyl phosphate using smartphone-assisted surface molecular imprinting, belonging to the fields of biochemical analysis, functional nanomaterials, and life science technology. In the synthesis process, the solubility, selectivity, and photoinitiation efficiency of the target analyte during polymerization are optimized, and molecularly imprinted nanozymes (MIPs) for diphenyl phosphate are rapidly prepared using molecular imprinting technology. In the detection process, the peroxidase-like activity of Fe,N-CDs catalyzes the colorimetric reaction between H₂O₂ and 3,3,5,5-tetramethylbenzidine (TMB), and the internal filtering effect of oxTMB suppresses the fluorescence signal. Combined with a smartphone, dual-signal cross-validation is achieved, constructing a colorimetric-fluorescence sensor for detecting diphenyl phosphate. This sensor exhibits specific recognition selectivity and binding affinity for diphenyl phosphate, is simple to operate, and low in cost. It can achieve sensitive detection of diphenyl phosphate over a wide linear range, with a detection limit as low as 16 pg / mL, making it suitable for on-site analysis of trace DPH in complex aquatic environments.

The application discloses a microbial nano-enzyme probe, a method for detecting salbutamol and application, and comprises a salbutamol monoclonal antibody and a signal carrier, wherein the signal carrier is a yeast cell loaded with iridium oxide nanoparticles. The application firstly constructs a probe by using a yeast cell loaded with iridium oxide nanoparticles in the detection of an immunochromatographic test strip, uses [3, 3', 5, 5' tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2)] as a substrate to trigger a color developing reaction, can realize high-sensitivity target detection, and the detection limit is as low as 0.012 ng / mL, which is 55 times higher than the sensitivity of a traditional gold-labeled test strip. In addition, the application has a good application prospect, can provide a universal platform for sensitive, accurate and rapid detection of food-borne stimulants, and can be successfully applied to the detection of salbutamol in pig liver and beef samples.

This invention discloses Ni-Fc MOF nanomaterials as Hg 2+ The application of the detection probe, the preparation method of the Ni-Fc MOF nanomaterial includes: 1,1-ferrocene dicarboxylic acid and water-soluble Ni at 110–130 °C. 2+ The Ni-Fc MOF nanomaterials were prepared by salt reaction. This invention is based on Hg... 2+ Sensitive and selective activation of oxidase activity by probes from flower-shaped Ni-Fc MOF nanomaterials was achieved, and a Hg assay was established using flower-shaped nanozymes as recognizers and 3,3',5,5'-tetramethylbenzidine as a signal generator. 2+ Colorimetric sensing method.

The invention provides a method for detecting the total antioxidant capacity of saliva based on iron-based MOF nano-enzyme, and belongs to the field of biosensing. The method comprises the following steps: obtaining an MIL-53Fe nano enzyme; the preparation method comprises the following steps: mixing a diluent of MIL-53Fe nano-enzyme, a sodium acetate buffer solution, 3, 3 ', 5, 5'-tetramethyl benzidine and hydrogen peroxide for reaction, adsorbing a reaction solution by using filter paper, drying and curing by using a chitosan solution to obtain the visual microfluidic detection paper-based chip. Establishing a standard curve of the chromatic value and the ascorbic acid concentration; dropwise adding the treated saliva sample onto the paper-based chip, standing for reaction to obtain a chromatic value, and calculating according to the standard curve to obtain the total antioxidant capacity value of the saliva. Complex matrix interference is broken through, the detection sensitivity and portability are improved, and therefore clinical application of saliva TAC detection in noninvasive health monitoring is promoted.

The invention discloses a nanogold and wood composite material, a preparation method, application and a method for determining the content of glucose in reconstituted tobacco, glucose oxidation is directly catalyzed through the nanogold and wood composite material (AuNPs and wood), the glucose and tetramethyl benzidine (TMB) are subjected to a chromogenic reaction, and the content of the glucose in the reconstituted tobacco is determined by combining the linear relation between absorbance and the glucose concentration. And whether the glucose exists in the reconstituted tobacco and the concentrated solution sample or not and the specific content of the glucose can be accurately judged. The method provided by the invention can quickly obtain a detection result within 30 minutes, is suitable for efficiently screening reconstituted tobacco and concentrated solution samples with the glucose content lower than 0.01 gL <-1 >, can accurately determine the actual content of glucose in the reconstituted tobacco and the concentrated solution, does not need to depend on a standard substance or carry out modeling maintenance, and is simple and convenient to operate. The equipment cost is obviously reduced; and the operation process is simplified.

The invention discloses a colorimetric-fluorescence dual-mode detection method for salmonella and escherichia coli, and belongs to the technical field of biological detection. According to the invention, concanavalin A (ConA) is coupled with magnetic nanoparticles (MNPs) to form MNPs (at) ConA as a capture probe by recognizing the characteristic of capturing bacteria by sugar residues, and in addition, an antibody (Ab) can specifically recognize bacteria and is coupled with quantum dots (QDs) to form QDs (at) Ab as a fluorescence signal probe. The invention finds that MNPs can catalyze 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) to generate blue oxTMB which can be observed by naked eyes; and the QDs have strong fluorescence and can also be observed by naked eyes, so that obvious distinguishing is realized in Sal and Esc detection. And the signal is linearly related to the target bacteria, so that the visibility is good. The practicability of the method is verified by detecting milk tea, milk and fruit juice samples, and the recovery rate is 93.5-106%. The feasibility of detecting Sal and Esc by the method is verified, and the method has important application potential in food safety monitoring.

The present invention provides a method for quantitative detection of uric acid based on enzyme-free colorimetric sensing, belonging to the technical field of analysis and detection. The present invention obtains a blue product TMBox by mixing a buffer solution, a porous Co3O4 catalyst and 3,3',5,5'-tetramethylbenzidine and then filtering; then uric acid liquid is added to reduce TMBox, and after the reaction is completed, the uric acid concentration is judged according to the absorbance change of TMBox. The Co3O4 prepared by the present invention can catalyze the oxidation of TMB without hydrogen peroxide, and the method for quantitative detection of uric acid by enzyme-free colorimetric sensing established based on this does not require natural enzymes and artificial enzymes, and the uric acid detection range is wide (0-600 μmol / L) and the detection limit is low (0.33 μmol / L). The method for quantitative detection of uric acid by enzyme-free colorimetric sensing constructed by the present invention is applied to quantitative detection of uric acid, and the detection method is simple, convenient for promotion and application, and the detection time period is only 2-4min, which can be widely used in the determination of uric acid content in body fluids.