251 results about "Color reaction" patented technology

The invention discloses application of iron ruthenium nano-enzyme in preparation of nucleic acid detection products, and belongs to the technical field of biological detection and nano-materials. The RIN has stable peroxidase-like (POD) activity, and can catalyze a chromogenic reaction between 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) and hydrogen peroxide (H2O2). The catalytic activity of the nano-enzyme can be selectively inhibited by pyrophosphate (PPi) generated in a nucleic acid amplification reaction, so that visual colorimetric analysis on whether target nucleic acid exists or not is realized. In combination with a polymerase chain reaction (PCR) system, the invention constructs a new nucleic acid detection strategy which does not need fluorescence labeling, is simple and convenient to operate and has high sensitivity. Through verification, the system can be widely applied to rapid on-site screening and visual interpretation of related nucleic acid of drug-resistant pathogens (such as ESKAPE flora) and the like, and has a good application prospect.

The invention discloses a dynamic leaching-spectrophotometric detection method for the release rate of nutrients in a slow-release fertilizer, and relates to the field of agrochemical analys.The detection method comprises the following steps that S1, a slow-release fertilizer sample is placed in a leaching column to be leached, and leachate is collected; s2, sequentially adding a masking agent solution and a chromogenic reagent into the leachate, and carrying out chromogenic reaction; s3, pumping the solution into a double-optical-path flow cell, and measuring absorbance values under a target nutrient characteristic absorption wavelength and a background interference characteristic wavelength; s4, calculating the corrected net absorbance; and S5, calculating the nutrient concentration, and drawing a nutrient release kinetic curve. By adopting a dual-wavelength synchronous detection and real-time dynamic subtraction correction algorithm, the method can eliminate system errors of time-varying background chromaticity, so that accurate and reliable absorbance readings can be obtained at the initial stage of nutrient release even if the nutrient concentration in the leachate is very low, thereby ensuring the authenticity of the initial stage of a release curve and improving the accuracy of nutrient release. And initial release kinetic parameters are accurately captured.

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 present invention provides a detection reagent and a detection method for calcium hardness, magnesium hardness and total hardness of water. The detection reagent comprises a liquid color developing component, a liquid buffer component, a first liquid masking agent component and a second liquid masking agent component. The liquid color developing component comprises a color developing agent that can react with both calcium ions and magnesium ions. The liquid buffer component adjusts the pH value of the color developing reaction to be greater than 12. The first liquid masking agent component is used to mask the calcium ions and magnesium ions in the water quality, and the second liquid masking agent component is used to mask the calcium ions in the water quality. The detection reagent can simultaneously measure the calcium hardness, magnesium hardness and total hardness in the water quality. The detection method has high accuracy, good parallelism, convenience and rapidity, and the detection time of the three indicators of calcium hardness, magnesium hardness and total hardness of a single sample is short.

The invention discloses a chemical chromogenic reaction time sequence characteristic analysis method based on a CNN-LSTM model, and aims to establish a relationship between a chemical reaction color characteristic signal and time change. The method comprises the following steps: firstly, pretreating a PAD (paper-based analysis device) by using a phenanthroline reagent, and then dropwise adding iron ion solutions with different concentration gradients; in a single-light-source and all-black environment, continuous image data in a reaction process is acquired, and a rich data set is obtained. Preprocessing the acquired image data, including operations of cutting, denoising, enhancing, normalizing and the like, and extracting effective image information; spatial features of each frame of image are extracted by using a convolutional neural network (CNN), the features are input into a long short-term memory network (LSTM), time dynamic features of color changes are learned, and finally a change rule of the color features along with time or a prediction result is output. The invention provides an efficient and accurate chemical chromogenic reaction dynamic analysis method which can be widely applied to the field of chemical reaction monitoring and analysis.

The invention discloses a lateral flow chromatography test strip for detecting perfluorooctanoic acid by combining gold nanoparticles, a nucleic acid aptamer and an antibody. According to the test strip, a nucleic acid aptamer marked by gold nanoparticles is combined with PFOA molecules to form a nucleic acid aptamer with a G-quadruplex structure, and then the nucleic acid aptamer with the G-quadruplex structure is specifically recognized and captured by an anti-BG4 antibody, so that specific visual detection of perfluorooctanoic acid is realized. After a sample is injected, a G-quadruplex structure formed by the PFOA and the nucleic acid aptamer acts with the anti-BG4 antibody coated on the test strip, so that the gold nanoparticles are agglomerated to generate a chromogenic reaction, the signal intensity can be detected by naked eyes or reading equipment, the visual detection limit is 10 mu M, and the equipment detection limit is 304 nM. The test strip has the advantages of high detection speed, high specificity and high sensitivity, and is suitable for field detection and rapid screening. Compared with a traditional method, the method realizes simple, convenient and economical detection of PFOA, and has a wide application prospect.

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.

To provide a thermochromic color memory composition that employs a specific ester compound and exhibits a color memory effect in a low temperature range.SOLUTION: A thermochromic color memory composition comprising at least: (i) an electron-donating chromogenic organic compound, (ii) an electron-accepting compound, and (iii) a specific reaction medium for controlling the chromogenic reaction of the component (i) and the component (ii), wherein the thermochromic color memory composition undergoes color change with a hysteresis width (ΔH) of 8 to 100°C in a color density-temperature curve, wherein a complete coloring temperature t1 is equal to or lower than -30°C, and a complete decolorizing temperature t4 is in a range of -25 to 15°C.SELECTED DRAWING: None

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 discloses an Au (at) Pt nano-enzyme probe as well as application and a kit thereof. The Au (at) Pt nano enzyme probe is composed of Au (at) Pt nano enzyme and a CD20 antibody; the CD20 antibody is modified on the surface of the Au (at) Pt nano-enzyme. According to the preparation method disclosed by the invention, the Au (at) Pt nano-enzyme with a core-shell structure and a hydrodynamic size stabilized at 25nm is synthesized through specific steps, and the Au (at) Pt nano-enzyme probe modified by the CD20 monoclonal antibody (Rituximab) is prepared, so that the traditional two-step immunohistochemical detection is replaced. A proper DAB buffer solution and a proper reaction solution are prepared, so that clear and accurate chromogenic reaction is initiated, and a solid guarantee is provided for the reliability of an immunohistochemical staining result. Compared with the prior art, the immunohistochemical process is simplified, the cost is reduced, the detection efficiency and accuracy are improved, and an efficient and reliable scheme is provided for clinical diagnosis and scientific research.

To bring an indication material into close adhesion to a concrete hole wall surface in a press-contact state to promote a color reaction of a phenolphthalein agent, thereby improving measurement accuracy.SOLUTION: A method for measuring the depth of neutralization of a concrete structure includes: inserting, into a bore 12, an indication material 1 that is a base material sheet 2 with an elongated shape carrying a phenolphthalein agent-containing layer 3 on its front side; inserting, into a bore space on a rear face of the indication material 1, an elastic tube 6 expandable in a radial direction by a fed fluid; feeding air into the elastic tube 6 to expand the elastic tube 6 in the radial direction, and pressing the indication material 1 against a hole wall surface from the rear face side to bring them into close adhesion in a press-contact state, thereby promoting a color reaction of a phenolphthalein agent; and after the lapse of a predetermined time, removing the fluid from the elastic tube 6 to shrink the elastic tube and drawing out the elastic tube from the bore 12, and pulling out the indication material 1 from the bore 12 and measuring the distance from a concrete opening end corresponding position of the indication material 1 to a coloration region, thereby measuring the depth of neutralization.SELECTED DRAWING: Figure 5

The invention belongs to the technical field of analytical chemistry, and relates to a method for identifying and detecting endogenous mercaptan of a high-activity oxidized nano-enzyme based on machine learning, which comprises the following steps: firstly, preparing a Mnx (DTPMP) nano-enzyme, then constructing a sensor array of one nano-enzyme, four reaction times, three targets and six parallel samples, and detecting the endogenous mercaptan in the Mnx (DTPMP) nano-enzyme. Constructing a sensor array of one nano enzyme, four reaction times, 7 concentrations and 6 parallel samples for each endogenous mercaptan; and finally, analyzing the data through hierarchical clustering analysis, linear discriminant analysis and a support vector machine to obtain an LDA score chart, an HCA map, an SVM confusion matrix and a concentration prediction map of the endogenous mercaptan. After a sample to be detected is subjected to a chromogenic reaction, the absorbance is measured, and the type and concentration of the endogenous mercaptan of the sample to be detected can be distinguished according to the obtained spectrum. The kit has good anti-interference performance, normal cells and cancer cells can be accurately identified according to the content of glutathione in the cells, and the severity of diseases can be judged according to the content of homocysteine in serum.

The invention relates to a colorimetric detection method for Tween-20 in a protein preparation, which comprises the following steps: diluting the protein preparation with a diluent for enzymolysis, carrying out chromogenic reaction by using dichloromethane and an ammonium iron thiocyanate system, and measuring absorbance by using a visible spectrophotometer. The diluent is composed of other components except protein and Tween 20 in the protein preparation; an enzyme used in the enzymolysis is protease K; the concentration of the protease K is preferably 200 mu g / ml; the enzymolysis temperature is preferably 55-57 DEG C; the enzymolysis time is preferably 3.5 to 4 hours.

The invention discloses a method for testing the concentration of ferric ions in a citric acid cleaning solution, when the cleaning solution is combined with a color developing agent, namely a potassium thiocyanate solution, the cleaning solution is acidized in advance, firstly, citric acid is easy to form a stable complex with Fe < 3 + > at a relatively high pH value to hinder a subsequent color developing reaction and titration, and the concentration of ferric ions in the citric acid cleaning solution is not influenced; the protonated citric acid is subjected to pre-acidification treatment, so that the complexing ability of the protonated citric acid is destroyed, free Fe < 3 + > is released, hydrolysis of Fe < 3 + > is inhibited, and Fe < 3 + > is ensured to participate in subsequent reaction in an ionic state; besides, the acid environment can reduce the oxidation rate of Fe < 2 + >, avoid the introduction of additional errors due to the fact that Fe < 2 + > is oxidized into Fe < 3 + >, and improve the accuracy of a Fe < 3 + > concentration test result, so that the citric acid complexing effect is eliminated through the pre-acidification treatment, meanwhile, the oxidation interference of Fe < 2 + > is inhibited, and the detection precision is improved.

The invention relates to an inflatable cabinet sealing device with a self-checking function, and relates to the technical field of electrical equipment sealing, the inflatable cabinet sealing device comprises an inflatable cabinet structure, the inflatable cabinet structure comprises a sealing unit, a prestress unit is arranged in the sealing unit, and a self-checking unit is arranged on the surface of the sealing unit. Through cooperation of the prestress unit and the sealing unit, continuous and uniform pre-tightening force is provided for the sealing cover through the elastic force of a spring and a mechanical clamping structure, the sealing performance of the gas-insulated switchgear is remarkably improved, the influence of environmental factors on the sealing performance is effectively resisted, the self-checking unit achieves automatic gas collection through a double-motor driving mechanism, and the sealing performance of the gas-insulated switchgear is improved. By combining the chromogenic reaction of the colorless phenolphthalein solution, the leakage can be visually detected without manual intervention, the detection efficiency and accuracy are improved, the overall structure gives consideration to the sealing reliability and the operation convenience, the maintenance cost is reduced, a guarantee is provided for long-term stability of the sealing performance of the gas-insulated switchgear, and the gas-insulated switchgear has remarkable practical value and technical advantages.

The invention discloses a red soil dry land soil microbial diversity detection method based on multicolor developing test paper, and belongs to the technical field of soil environment microbial detection. According to the method, test paper loaded with different color developing agents is designed, a specific color developing reaction is triggered by combining microbial metabolic activity, and color developing characteristics are converted into parameters such as microbial diversity indexes and dominant species proportions by utilizing an image analysis model. The detection device comprises an image acquisition module and a data analysis module, and quantitative association of color development features and diversity is realized through a machine learning model. Compared with the prior art, the method has the advantages that the cost is extremely low, the detection time is shortened to be within 30 minutes, the method is suitable for field real-time monitoring of the red soil dry land, an efficient, low-cost and portable detection tool is provided for soil health management, and the method is particularly suitable for soil health assessment of resource-limited areas.

The invention discloses a Hedyotis diffusa extract, comprising a hedyotis diffusa glycoside content of 2500-4000 ppm, deacetylated hedyotis diffusa methyl ester, scutellariae glycoside methyl ester, and hedyotis diffusa glycoside content of 4500-6500 ppm, a total flavonoid content of less than 100 ppm, no characteristic color reaction for anthraquinone identification, hedyotis diffusa acid content of less than 100 ppm, deacetylated hedyotis diffusa acid content of less than 100 ppm, and geniposide acid content of less than 100 ppm, and a pH value of 6.0-7.0. The extract is obtained by vacuum ultrasound, centrifugation, and vacuum concentration, followed by acid adjustment to a pH of 2.5-3.0, followed by aging, membrane filtration, and purification by ion exchange column chromatography to obtain a permeate A and a Hedyotis diffusa alkaloid eluate J1. The permeate A is filtered through a membrane, separated by molecular imprinting polymerization adsorption, vacuum concentrated, and ultrafiltered. Finally, the pH is adjusted to 6-7 with J1, and the extract is sterilized by heat preservation.

The utility model provides a portable chromogenic reaction device, and relates to the technical field of detection. The portable chromogenic reaction device comprises a base, a first reaction cavity and a second reaction cavity, wherein the base is provided with an indentation line extending in the width direction of the base, the upper surface of the base is covered with a removable sealing layer, and the sealing layer is used for achieving airtight storage of the device; the first reaction cavity is arranged on the base in a protruding manner, and a pre-reaction reagent is pre-arranged in the first reaction cavity; the second reaction cavity is arranged on the base in a protruding mode, the first reaction cavity and the second reaction cavity are located on the same side of the base, and a color developing element is arranged in the second reaction cavity in advance. The first reaction cavity and the second reaction cavity are arranged on the two sides of the indentation line respectively, and when the base is folded along the indentation line, the second reaction cavity can be pressed to deform, so that the color developing element in the second reaction cavity is mixed with the liquid in the first reaction cavity. The device is portable, and the detection process is simplified at least to a certain extent.

The application provides a human Helicobacter pylori detection method and kit based on the nature of four-strand DNA oxidoreductase. The method uses isothermal amplification technology, amplifies the genomic fragment containing the four-strand DNA sequence in the human Helicobacter pylori genome, and realizes rapid and visual detection of the human Helicobacter pylori by adding hematin and oxidoreductase substrate for color reaction.

The application discloses a cyanide-containing slag tailing pond groundwater environment risk early warning system, a groundwater monitoring well subsystem comprises a plurality of groundwater monitoring wells; a timing sampling control subsystem is used for controlling the pumping time, flow and frequency of a water pump in each groundwater monitoring well; a color reaction subsystem comprises a color developing device and is used for monitoring the color developing reaction of the groundwater sample; a color sensing subsystem comprises a light source and a color sensor, the light source is irradiated towards the color developing device, and the color sensor is used for collecting the emergent light signal of the color developing device after the color developing reaction; a central control platform comprises an early warning subsystem and an emergency disposal response subsystem, the early warning subsystem receives the color sensor signal and divides the risk grade according to the obtained signal; the emergency disposal response subsystem executes corresponding detection and repair responses according to the risk grade made by the early warning subsystem; the application realizes the rapid detection of the cyanide content in the groundwater around the cyanide-containing slag tailing pond and the feedback and early warning of the environmental pollution risk grade.

Provided are: a fermented saccharified liquid of rice koji cereals containing beta-glucan derived from cereals; a food or beverage containing the fermented saccharified liquid of rice koji cereals; and a raw material for producing the food or beverage. The rice koji cereal fermentation saccharified liquid has the following characteristics: (a) the weight-average molecular weight of beta-glucan derived from cereal is 100,000-500,000, and the weight-average molecular weight of beta-glucan derived from cereal is 2,000-2,000,000; (b) the proportion of cereal-derived beta-glucan having a molecular weight of 10,000 or more and less than 800,000 in a total of 100 mass% of cereal-derived beta-glucan: 80 mass% or more; (c) the ratio of cereal-derived beta-glucan in 100% by mass of the solid content of the rice koji cereal fermentation saccharified liquid is 1-35% by mass; (d) iodine color development test: (-); and (e) a viscosity of 10 to 5000 mPa * s.

This utility model discloses a portable rapid detector for pesticide residues in food, comprising: a sample container, a tube head integrally installed on the top of the sample container, and a top cover installed above the tube head. A threaded sleeve is fixedly connected to the bottom surface of the top cover, and a docking hole is hollowed out in the middle of the top cover. A cap is installed on the top of the top cover by connecting bolts, and a reagent tube is installed inside the docking hole. The reagent tube is continuously fed into the sample container through the threaded connection structure between the top cover and the sample container. A rubber stopper is provided at the bottom of the reagent tube. Inserting the tube will puncture the rubber stopper at the bottom of the reagent tube. A through hole is provided on the surface of the inserting tube. After the inserting tube is inserted into the reagent tube, the reagent will flow into the sample container through the through hole on the surface of the inserting tube. After shaking the sample container, the reagent comes into contact with the agricultural product sample. Pesticide residues will cause the reagent to produce a color reaction. The color reaction is observed through the observation window on the surface of the sample container. The presence of pesticide residues can be quickly determined after the color reaction occurs.

The present disclosure relates to a diagnostic cartridge for immunodiagnosis, and a reader and a diagnostic system using the same. A diagnostic cartridge, including the diagnostic pad and the color reaction pad, is provided to detect a color reaction and a fluorescence reaction through the single diagnostic cartridge.

To provide a water-based ink composition for a ballpoint pen, which is excellent in dry-up resistance and can form clear handwriting, and to provide a ballpoint pen containing the ink composition.SOLUTION: An aqueous ink composition for a ballpoint pen, comprising: a colorant; an alkyl polyglucoside having a C8 to C14 aliphatic-hydrocarbon group; a shear-thinning agent; and water. The colorant contains a reversible thermochromic microcapsule pigment containing a reversible thermochromic composition comprising at least (a) an electron-donating color-developing organic compound, (b) an electron-accepting compound, and (c) a reaction medium for determining the temperature at which the color development reaction of the components (a) and (b) occurs.SELECTED DRAWING: None

The application belongs to the technical field of circuit board detection, and particularly relates to a circuit board cavity residual detection, identification and analysis method. The method first locates a suspected residual area according to the gray difference of an X-ray image and generates a spatial coordinate set thereof, then, combines chemical color reaction intensity and X-ray profile characteristics to screen out a to-be-analyzed area set, further divides the area set into a plurality of subsets according to spatial diffusion characteristics, obtains element and functional group data of each area through energy spectrum and spectrum analysis, analyzes a candidate residual class thereof, dynamically adjusts subset division based on consistency of the candidate class in the subset, until the consistency requirement is met, and finally outputs a specific residual class for each area according to the division result. According to the spatial proximity and profile characteristics, the application realizes systematic differentiation and classification of diffusion-type residues and adhering-type residues, and improves the accuracy of class determination.

The invention relates to a color developing solution for detecting iron metal foreign matters in a lithium battery production process and a detection method, and the color developing solution comprises the following components in parts by volume: 3-4 parts of an acid solution, 1-2 parts of an oxidizing agent and 3-4 parts of a thiocyanate solution. The color developing solution is provided for detection of the iron metal foreign matter in the lithium battery production process, the iron metal foreign matter in the lithium battery production process is rapidly and qualitatively detected by utilizing a color developing reaction of ferric ions and thiocyanate ions to generate a blood red complex iron thiocyanate, and the detection sensitivity, the detection efficiency and the speed are high; the reagent of the color developing solution is nontoxic and harmless, the cost is low, the color developing solution is particularly suitable for large-batch detection on a mass production line, the detection efficiency of the production line is greatly improved, and meanwhile, high detection sensitivity is taken into account.

The invention discloses a method for enabling people to predict whether a beverage contains GBL or not in advance. Based on the principle that a purple complex is immediately formed by mixing and reacting GBL and an alkaline hydroxylamine solution and then adding acidic ferric chloride, reaction conditions are optimized, the relationship between the concentration of GBL in a beverage and the degree of chromogenic reaction is researched, and an optimal use method of portable qualitative test paper capable of being used on site is designed. The detection shows that the obvious change of colors of various drinks can be detected, and on the basis of not influencing continuous drinking, whether a sample contains GBL with the dosage exceeding the safe dosage or not can be detected within one minute, and the detection limit is 1 mu l / ml and is within the edible safety limit. The method is simple to operate, quick in reaction, low in cost and hopeful for large-scale production.

The invention belongs to the technical field of microbiological detection, and relates to a method for detecting the ability of microorganisms to degrade nitrogen-containing heterocyclic compounds and application of the method. The technical problems that in the prior art, a color developing system for directional detection of the degradation capacity of a nitrogen-containing heterocyclic compound is lacked, and traditional absorbance detection has false positive and low accuracy are solved. The detection method provided by the invention comprises the following steps: inoculating bacteria to be detected into a culture medium taking a nitrogen-containing heterocyclic compound as a unique carbon source to prepare a bacterial suspension with initial OD600 of 0.4-0.6; the bacterial suspension and a color developing agent WST-8 or XTT are subjected to a color developing reaction, a reaction solution is obtained, and the initial concentration of the color developing agent in the reaction solution is 250-350 mg / L; the absorbance difference value of the reaction liquid is measured by adopting a dual-wavelength spectrophotometric method and is used for representing the degradation capability of the bacteria to be detected on the nitrogen-containing heterocyclic compound, and the method is high in accuracy. The invention also provides an application of the method in screening nitrogen-containing heterocyclic compound degrading bacteria.

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 provides a double-layer structure colorimetric test paper for medical equipment occult blood detection and a preparation method and application thereof, and belongs to the technical field of hospital infection control and cleaning quality monitoring. The colorimetric test paper adopts a double-layer structure design: the bottom layer is obtained by immersing qualitative filter paper in immersion liquid A and drying, and is used for storing oxidant stably; and the upper layer is formed by uniformly coating coating liquid B on the surface of the bottom layer, and is used as a chromogenic substrate layer. When in use, hemoglobin remaining on the surface of the medical equipment can catalyze H2O2 in the bottom layer to oxidize TMB in the upper layer, a blue color reaction is generated, and naked-eye visual judgment is realized. The test paper physically separates the oxidant and the substrate, significantly improves the storage stability and detection sensitivity, and has the advantages of simple preparation process, low cost, convenient operation, and the like. The test paper is suitable for on-site rapid evaluation of cleaning effects of surgical instruments, endoscopes and the like, and has good clinical application prospect and popularization value.