358 results about "Analytic chemistry" patented technology

The invention discloses an unknown pollutant non-target identification method and system based on mass spectrum and a generative model, and is applied to the technical field of environmental monitoring and analytical chemistry. The method comprises the following steps: collecting mass spectrum data of a water body sample to be detected; preprocessing the original mass spectrum data, and outputting standardized features; inputting the standardized features into a pre-trained generative model to generate a plurality of candidate molecular formulas; using chemical and physical constraints to eliminate candidate molecular formulas which do not conform to rules; executing a rule-driven algorithm to obtain candidate pollutant molecular structures; carrying out comprehensive scoring and sorting on candidate pollutant molecular structures through chemical prior and environmental prior; and semi-quantitative or relatively quantitative concentration determination is carried out. According to the method, a rule-driven expert system and a data-driven generation model are combined, unknown pollutants which do not exist in a standard library can be effectively recognized and analyzed, and full-process automatic processing from original mass spectrum data to pollutant structures and concentrations is achieved.

The invention belongs to the field of analytical chemistry, relates to material preparation, and particularly discloses a preparation method of a copper-doped covalent organic framework and application of the copper-doped covalent organic framework in adrenaline colorimetric detection. Firstly, 1H-indazole-4, 7-diamine (Iz) and 1, 3, 5-triformyl phloroglucinol (Tp) are used as monomers to synthesize a novel covalent organic framework (Iz-Tp COF) through a Schiff base reaction, copper ions are introduced into the Iz-Tp COF framework to prepare a novel metal covalent organic framework (Iz-Tp (at) Cu), and then according to the phenomenon that the Iz-Tp (at) Cu can catalyze oxidation color development of epinephrine, the metal covalent organic framework (Iz-Tp (at) Cu can catalyze oxidation color development of epinephrine. According to the present invention, the simple, sensitive and efficient adrenaline colorimetric detection method is established, the test conditions are finally optimized, the standard addition method is combined to accurately determine the adrenaline concentration in the urine, and the good practical application value is provided.

The invention discloses construction and application of a confinement enhanced photoelectrochemistry-electrochemiluminescence dual-mode biosensor, and relates to the technical field of biosensing and analytical chemistry. The preparation method of the biosensor comprises the following steps: taking a CdS (at) SiO2 (at) NaYF4: Yb / Tm nano composite material as a substrate to obtain a confinement enhanced photoelectrochemistry (PEC) and electrochemiluminescence (ECL) sensing interface; in combination with a DNA wheel nanostructure triggered by target acetamiprid, signal amplification is realized; and synchronous dual-mode quenching detection of PEC and ECL signals is realized by virtue of peroxidase-like catalytic precipitation and wide-spectrum absorption characteristics of the PtPd-CoSnO3 nanocube. The biosensor prepared by the invention has the advantages of high sensitivity, strong reliability, good selectivity and the like, can be applied to accurate detection of acetamiprid in samples such as agricultural products and the like, and has important application value in the aspects of environmental monitoring and food safety control.

The invention relates to the technical field of environmental analytical chemistry, and discloses a thymol phenolphthalein-TBPE double indicator-based cyanide titration detection method and system, and the method comprises the following steps: adjusting a water sample to be detected to an alkaline pH interval to construct a detection matrix; the method comprises the following steps: introducing a double-indicator system composed of thymol phenolphthalein and tetrabromo phenolphthalein ethyl ester according to a specific ratio into a detection matrix, and constructing a spectrum background for masking yellow interference of sulfide by utilizing the blue color development characteristic of thymol phenolphthalein; dropwise adding a silver nitrate standard solution into the mixed system to execute a complex reaction; according to the method, a spectrum background shielding field is constructed, chromaticity response of a system in a specific wave band is monitored in real time, and when a chromaticity mutation signal from green to bluish violet is captured, a titration end point is judged, and the cyanide concentration is calculated. High-precision anti-interference detection on cyanide in a complex high-turbidity matrix is realized, and the sensitivity and accuracy of end point recognition are improved.

The invention relates to the technical field of analytical chemistry, in particular to a high performance liquid chromatography detection method of a ridecevir intermediate GS-441524, which comprises the following steps: preparing a sample: taking a GS-441524 test sample, dissolving and diluting with a mixed solution composed of dimethyl sulfoxide and a phosphoric acid solution to prepare a test sample solution; the volume fraction of phosphoric acid in the phosphoric acid solution is 0.05-0.1%, and the volume ratio of dimethyl sulfoxide to the phosphoric acid solution is (30: 70)-(60: 40). According to the application, the ridecevir intermediate GS-441524 is dissolved and diluted through the mixed solution composed of the dimethyl sulfoxide and the phosphoric acid solution, and due to the high solubility of the dimethyl sulfoxide to the ridecevir intermediate GS-441524 and the high boiling point of the dimethyl sulfoxide, the ridecevir intermediate GS-441524 with relatively high concentration can also be subjected to high performance liquid chromatography.

The present application relates to the field of analytical chemistry, in particular to a method for detecting ten tobacco alkaloids in soil, which uses sodium hydroxide solution and acetonitrile to extract alkaloids in a soil sample, and uses ultra-high performance liquid chromatography-triple quadrupole mass spectrometry to analyze and detect nicotine, nornicotine, myosmine, pseudotropine, anatabine, anabasine, 2,3'-bipyridine, noranatabine, N-methyl pseudotropine and nornicotine, and uses an internal standard method for quantitative analysis. The present application uses sodium hydroxide solution as an alkaloid eluent and acetonitrile as an extractant, which reduces the amount of solvent used, optimizes the operation process, uses sodium chloride to separate the organic phase and the aqueous phase, improves the sample pretreatment efficiency, uses ultra-high performance liquid chromatography-triple quadrupole mass spectrometry to target analysis of 10 tobacco alkaloids, greatly improves the detection sensitivity, and has strong quantitative ability in targeted analysis.

The application relates to the technical field of analytical chemistry detection, and specifically discloses a rare earth ion chromatographic online analysis and detection method and system, which adopts a chromatography-mass spectrometry combined system, realizes multi-scale time-frequency decomposition of signals by constructing an adaptive wavelet base function library, accurately identifies and classifies interference types in combination with a convolutional neural network and vacuum degree coupling analysis; a U-Net generator with an attention mechanism and a multi-scale discriminator are designed for signal repair aiming at repairable interference; a state transition model containing a mass-to-charge ratio database is established, empirical mode decomposition and adaptive filtering technology are used to realize dynamic calibration of a mass axis; quantitative accuracy is ensured through double internal standard correction and a triple verification mechanism; when unrepairable interference is detected, a hierarchical self-checking program is started, and fault diagnosis is carried out in combination with spectrum fingerprint analysis.

The invention discloses a method for determining the content of rubber in a rubber-containing plant based on gel permeation chromatography, and relates to the technical field of analytical chemistry, and the method specifically comprises the following steps: S1, sample pretreatment: drying a rubber-containing plant sample and grinding into powder; s2, rubber extraction: performing ultrasonic extraction on the powder by using a mobile phase of gel permeation chromatography as an extraction solvent, centrifuging, and collecting supernate to obtain an extracting solution; s3, GPC (Gel Permeation Chromatography) detection: filtering the extracting solution, and injecting the filtered extracting solution into a gel permeation chromatographic instrument with a single chromatographic column for detection. The complete plant rubber content determination method is constructed by combining a total rejection GPC principle with an efficient sample pretreatment process, the defects of tedious pretreatment, low detection efficiency or inaccurate detection in the prior art are overcome, the method has the advantages of rapidness, accuracy and the like, extraction and detection parameters can be flexibly adjusted according to different plant samples, and the method is suitable for large-scale popularization and application. The method is suitable for quality analysis and breeding research of various gelatin-containing plants, so that the compatibility is improved.

The invention relates to a preparation method of a molecularly imprinted composite filler, and relates to the technical field of analytical chemistry and environmental monitoring technologies, the preparation method of the molecularly imprinted composite filler comprises the following steps: firstly dissolving template molecules and a first monomer, then adding a cross-linking agent and an initiator, carrying out deoxidation and water bath, and then centrifuging to obtain a template molecule solution; and eluting the precipitate with a flushing fluid, and drying to obtain the microspheres. And dissolving the ionic liquid, uniformly stirring with the obtained microspheres, and carrying out centrifugal separation, washing and vacuum drying to finally prepare the molecularly imprinted composite filler. Finally, the hydrophobic property of the molecularly imprinted composite filler is improved through modification of the ionic liquid and the second monomer. The method provided by the invention has excellent hydrophobic effect and enrichment capability on a target object.

The invention discloses a fluorescence sensing system based on nitrogen-doped carbon dots and machine learning and application of the fluorescence sensing system in recognition of benzenediol isomers, and belongs to the technical field of analytical chemistry and artificial intelligence. According to the invention, the undoped carbon dots and the nitrogen-doped carbon dots of which the properties change in a gradient manner are utilized to form the probe library, the carbon dots in the probe library can perform collaborative recognition, and weak differences between analytes are accumulated and amplified. Although the response difference of each single probe in a probe library to two similar isomers is very small, the tiny differences can be accumulated and amplified in a high-dimensional response vector due to the gradient change of the properties of the probes; the microscopic chemical property difference, which is difficult to directly measure, between the isomers is converted into the macroscopic high-dimensional data mode difference which can be easily identified by a machine, so that the accurate identification and classification of the structural similar substances and the mixture thereof are realized.

The invention discloses an in-situ ultraviolet and visible spectrophotometer with high measurement precision, and relates to the technical field of ultraviolet and visible spectrophotometers, the in-situ ultraviolet and visible spectrophotometer comprises a bottom shell, an optical unit is arranged on the inner wall of the bottom of the bottom shell, and a light source module and a monochromator are arranged in the optical unit; the top of the optical unit is fixedly connected with an operation platform through a supporting rod, the top of the operation platform is provided with a motor mounting frame, the top of the motor mounting frame is provided with a linear motor, the output end of the linear motor is connected with a lifting fixing plate, and the lifting fixing plate is of a Z-shaped structure. The end, away from the linear motor, of the lifting fixing plate is connected with a light shield, and the top of the light shield is provided with an optical fiber clamping frame. According to the method, result deviation caused by dilution multiple estimation errors in a traditional method is avoided, the dilution frequency of the high-concentration sample is reduced, reagent consumption and waste liquid generation are reduced, and the method conforms to the green analytical chemistry concept.

The application relates to a method for enhancing electrochemiluminescence signals by ion-pi interaction, belonging to the fields of electrochemiluminescence and analytical chemistry. 2+ By modifying the working electrode with a conjugated pi system, cation-pi interaction is introduced into the Ru(bpy)3 / triethylamine (TEA) system, efficient enrichment of TEA protonated cations near the electrode is realized, thereby greatly enhancing the electrochemical reaction rate and ECL signal. Further, anion-pi interaction is utilized to realize ECL signal enhancement of the luminol ECL system. In addition, the conjugated pi system is exposed to the outermost boundary of the electrode, so as to provide effective ion-pi interaction for ECL; when the pi system is covered by an alkyl chain, the modified electrode can only exhibit hydrophobic interaction. The method disclosed by the application provides a new strategy for extending ion-pi interaction to all types of ECL systems and constructing a high-sensitivity ECL analysis platform.

This application relates to the field of analytical chemistry detection technology, and in particular to a sample rack for a liquid chromatography-mass spectrometry (LC-MS) instrument used for TDM detection. The rack includes a support mechanism with a sample placement box at the top and a heat-insulating mechanism at the top. The invention utilizes components such as a pull-out plate, a spare support plate, and a table. The sliding engagement between the pull-out plate and the table allows for convenient horizontal sliding of the pull-out plate to retrieve and place samples placed in a first positioning slot. Simultaneously, the spare support plate is fixedly connected to a support side plate, enabling the categorized storage of samples after testing. These components work together to form an orderly sample management system, achieving the modular, partitioned design that efficiently distinguishes and quickly retrieves samples in different testing states, significantly improving the convenience and standardization of experimental operations.

The invention relates to the technical field of analytical chemistry detection, in particular to a method for determining trace nitrite in pharmaceutic adjuvants.The method comprises the steps that an acetonitrile solution, a potassium hydroxide solution, a phosphate buffer solution, a sulfuric acid solution, a 2, 3-diaminonaphthalene solution and a reference substance working solution are provided; the method comprises the following steps: preparing a standard curve solution and a test sample solution, and carrying out ultra-high performance liquid chromatography-tandem mass spectrometry analysis detection: respectively carrying out sample injection detection on the test sample solution and the prepared standard curve solutions with different concentrations under preset chromatographic conditions and mass spectrometry conditions, recording detection results of the standard curve solutions with different concentrations to make a standard curve, and calculating the content of nitrite in the test solution by adopting a standard addition method according to the standard curve and the detection result of the test solution. The method disclosed by the invention can be used for rapidly determining trace nitrite in a drug sample, and can be used for determining the trace nitrite in pharmaceutical adjuvants and detecting the nitrite in drugs.

The application relates to the technical field of analytical chemistry, in particular to a high-performance liquid chromatography analysis method for maleic acid olmutant, wherein the mobile phase in the high-performance liquid chromatography condition comprises mobile phase A and mobile phase B, the mobile phase A is a mixed solution, the mixed solution comprises trifluoroacetic acid, triethylamine and water, the volume fraction of trifluoroacetic acid in the mixed solution is 0.08-0.12%, the volume fraction of triethylamine is 0-0.3%, the mobile phase B is acetonitrile, and the volume ratio of the mobile phase A and the mobile phase B is 75:25-85:15. The trifluoroacetic acid and the triethylamine in the mobile phase are matched, the interaction between maleic acid olmutant and a chromatographic column is hindered, the peak shape is symmetrical, and peak tailing is significantly improved; meanwhile, the two can also form a buffer system; in addition, the trifluoroacetic acid can enhance the retention capacity of maleic acid olmutant on the chromatographic column and improve separation selectivity.

This invention discloses an isotope abundance detection method and system based on the centroid method of emission spectroscopy, belonging to the fields of analytical chemistry and spectroscopic analysis technology. This method measures the centroid position of the atomic spectral lines or molecular spectral bands of the target element, utilizing the quantitative relationship between the centroid position and isotope abundance to achieve rapid, accurate, and low-cost detection of isotope abundance. This invention is the first to systematically establish a complete theoretical framework for the use of the centroid method of emission spectroscopy for isotope abundance detection, revealing the strict linearity conditions between the centroid and abundance, as well as the sources of error. This method is applicable to various excitation sources such as microwave plasma, inductively coupled plasma, and laser-induced breakdown plasma, covering both atomic and molecular spectroscopy detection modes, significantly reducing the resolution requirements of the spectrometer and exhibiting good noise interference resistance. This invention can be widely applied in fields such as nuclear engineering, semiconductor industry, environmental science, geochemistry, and medicine.

The present application belongs to the technical field of three-dimensional fluorescence spectrum analysis, chemometrics and machine learning, and discloses a traditional Chinese medicine harvest period identification method, system and electronic equipment fusing three-dimensional fluorescence and machine learning, aiming at the problems of long time consumption of traditional Chinese medicine harvest period identification methods, insufficient precision of existing spectrum analysis and weak model generalization ability, comprising: obtaining three-dimensional fluorescence spectrum data of the traditional Chinese medicine to be identified; after background and scattering subtraction, extracting fluorescence intensity through a weight self-adaptive alternating trilinear decomposition algorithm; substituting the fluorescence intensity into an improved prediction model to output a harvest period prediction value. The present application combines the fast and efficient advantages of three-dimensional fluorescence spectrum with the precise analytical ability of high-order matrix decomposition and machine learning, realizes fast, accurate and stable identification of the harvest period of traditional Chinese medicine through feature weighting screening, batch difference correction and harvest period interval penalty optimization, adapts to batch detection requirements, reduces detection cost and provides technical support for quality control of traditional Chinese medicine.

The present application relates to the field of analytical chemistry, and provide a kind of method for detecting complex matrix of agricultural products in guanidine morpholino salt hydrochloride.The extraction solvent of the present application uses acetonitrile+acid+aqueous solution, different acid is selected according to the water content of sample, trifluoroacetic acid is used for high water content sample, and formic acid is used for low water content sample;In purification, pH value is adjusted according to the oil content of sample, ammonia is used to adjust pH to 8.5 for high oil content sample, and pH value can not be adjusted for low oil content sample.In the method, NaCl is not added to make organic phase and aqueous phase in extraction liquid stratified, through the way of extracting three times repeatedly, the recovery rate of the method is guaranteed;And using ultra-high phase liquid chromatography triple quadrupole mass spectrometry technology, guanidine morpholino salt hydrochloride in complex matrix of agricultural products is successfully detected, the extraction method is fast and simple, the quantitative limit of guanidine morpholino salt hydrochloride in tea is 0.1mg / kg, and the quantitative limit in other matrix is 0.05mg / kg, which is suitable for routine analysis, and can meet the quantitative detection requirements of guanidine morpholino salt hydrochloride in complex matrix of agricultural products.

The application discloses a kind of detection flavonoid compound magnetic composite material, preparation, detection method and the application of preparation standard substance, belong to analytical chemistry technical field.Magnetic composite material includes magnetic nanoparticle core, double lanthanide series metal organic framework (MOF) first shell and covalent organic framework (COF) second shell successively coated on its surface, and phenylboronic acid group grafted on the surface of second shell.The material uses the specific covalent binding of phenylboronic acid and the characteristic ortho-diphenol hydroxyl group of flavonoid compound to realize efficient capture and enrichment;Through double lanthanide series MOF shell, promote energy transfer, COF shell provides high specific surface area and ordered diffusion channel, and magnetic core is convenient for rapid separation, which realizes high selectivity identification of flavonoid compound.The material has the advantages of high sensitivity, strong anti-matrix interference ability, rapid and simple detection, etc., and is suitable for accurate analysis of flavonoid compound in complex sample and development of related standard substance.

This invention belongs to the field of analytical chemistry technology, specifically relating to a composite indicator and testing method for determining cadmium content in crude cadmium. The composite indicator comprises xylenol orange, thymol blue, and sodium indigo disulfonate, with a mass ratio of xylenol orange, thymol blue, and sodium indigo disulfonate of 1.0–1.5:0.3–0.6:0.5–1.0. This invention utilizes the ternary compound of xylenol orange, thymol blue, and sodium indigo disulfonate, employing the blue background of sodium indigo disulfonate and the reddish-purple and yellow hues of xylenol orange for optical color adjustment. This transforms the color change at the titration endpoint from the traditional reddish-purple to yellow to a bluedish-purple to yellowish-green, significantly increasing the color difference and creating a clear and sharp color change interface, greatly improving the accuracy and reliability of visual endpoint determination.

This invention discloses a method and application for detecting fentanyl and toluenethiazide using a microfluidic chip coupled with ion mobility spectrometry (IMS), belonging to the field of analytical chemistry. The method utilizes a microfluidic chip platform coupled with IMS for detection, specifically including the following steps: using a dual-channel microfluidic chip platform filled with adsorbent material, fentanyl and toluenethiazide are enriched in the sample to be tested; then, IMS is used to detect the enriched fentanyl and toluenethiazide in the sample. The detection method provided by this invention has high repeatability, minimizes operator exposure to drugs throughout the process, and greatly improves the accuracy and detection efficiency. Furthermore, the detection method provided by this invention has a short testing time, high sensitivity, and is automated and environmentally friendly, enabling rapid screening of fentanyl and toluenethiazide in multiple matrices.

The invention relates to the technical field of analytical chemistry, in particular to a high performance liquid chromatography analysis method of olatinib maleate, a mobile phase in high performance liquid chromatography conditions comprises a mobile phase A and a mobile phase B, the mobile phase A is a mixed solution, the mixed solution comprises trifluoroacetic acid, triethylamine and water, and the mobile phase B is a mixed solution. The mobile phase A is a mixed solution, the volume fraction of trifluoroacetic acid in the mixed solution is 0.08-0.12%, the volume fraction of triethylamine in the mixed solution is 0-0.3%, the mobile phase B is acetonitrile, and the volume ratio of the mobile phase A to the mobile phase B is 75: 25-85: 15. According to the invention, through the cooperation of trifluoroacetic acid and triethylamine in a mobile phase, the interaction between the oxilatinib maleate and a chromatographic column is hindered, so that the peak shape is symmetrical, and the peak trailing is obviously improved; meanwhile, the two can form a buffer system; in addition, the trifluoroacetic acid can enhance the retention capacity of the olatinib maleate on the chromatographic column and improve the separation selectivity.

The invention relates to the technical field of bioanalytical chemistry, in particular to a gold nanoparticle detection method for realizing multi-microorganism detection. The preparation method comprises the following steps: synthesizing gold nanostars with rich tip structures by adopting a surfactant-free reduction method, taking the gold nanostars as a high-activity SERS substrate, coding by utilizing different Raman reporter molecules, and coupling a specific antibody through a heterobifunctional PEG (Polyethylene Glycol) connecting arm to prepare the multiple SERS immune nano-label; meanwhile, functional immunomagnetic nanoparticles are constructed and are used for capturing and enriching target bacteria from a complex sample. The detection process adopts a magnetic enrichment-compounding-SERS spectrum reading mode to form a magnetic bead-bacteria-SERS label compound, and a portable Raman spectrometer is used for collecting signals and combining a deconvolution algorithm to realize synchronous qualitative and quantitative analysis of various pathogens. The method disclosed by the invention has the advantages of high detection sensitivity, high detection speed, strong matrix interference resistance, no spectral crosstalk due to multiple detection and the like.

This invention relates to the field of analytical chemistry, and in particular to a method for the quantitative determination of total phosphate in aquatic products using acid hydrolysis combined with liquid chromatography-tandem mass spectrometry. The method exhibits good linearity for orthophosphate in the range of 0.1–20.0 mg / L, with a correlation coefficient of 0.9991, a limit of detection of 0.03 g / kg, a limit of quantitation of 0.10 g / kg, and low matrix effect. At spiking levels of 1.0–10.0 g / kg, the intra-day recoveries for shrimp and fish are 89.8%–102.8% and 88.7%–105.8%, respectively; the inter-day recoveries are 90.9%–106.4% and 90.2%–105.8%, respectively; the intra-day RSD is ≤10.0%, and the inter-day RSD is ≤9.6%. This method features simple pretreatment, strong anti-interference capabilities, high sensitivity, and excellent accuracy and precision. It is suitable for the detection of total phosphate in aquatic products, providing a reliable technical means for the supervision of total phosphate in aquatic products, and is highly practical.

The application discloses a controllable liquid level parallel automatic solid phase extraction instrument, and belongs to the field of analytical chemistry sample pretreatment. The extraction instrument comprises a liquid adding system, a solid phase extraction column array unit and a collecting tube device which are electrically connected with a control system. The solid phase extraction column array unit is arranged below the liquid adding system, and the collecting tube device is arranged below the solid phase extraction column array unit. The liquid adding system comprises a liquid adding pipe for adding reagents to the solid phase extraction column array unit. The extraction column has the function of automatically controlling or maintaining the liquid level, and the diameter and height of each component of the extraction column can be flexibly adjusted according to the requirement. The liquid level in the extraction column can be monitored, all the extraction columns can simultaneously and in parallel process samples, and the sample processing efficiency and reliability are improved.

This invention relates to the field of analytical chemistry, and discloses an isotope dilution-bismuth reagent-LA-ICP-MS method for the determination of noble metals. The method involves adding geochemical samples to bismuth reagent kits... 194 Pt isotope diluent was mixed with a silver carrier, and then melted and blown to obtain silver alloy particles. The silver alloy particles were annealed and pressed into silver sheets. The content of Pt in the silver sheets was determined by LA-ICP-MS. 105 Pd, 195 Pt and 197 The mass spectrometry intensity of Au was determined by adding platinum isotope diluent. 194 Pt was used as an internal standard for signal correction; the contents of gold, platinum, and palladium in the sample were calculated based on the measurement results. This invention utilizes solid-state injection of prepared Ag sheets and multi-point ablation by LA-ICP-MS, improving the analysis speed and avoiding interference from polyatomic ions and dilution effects in the solution; the added platinum isotope diluent... 194 Pt, as an internal standard, is consistent with the distribution trend of the element to be measured, thus solving the problem of uneven element distribution in Ag tablets. Ag tablets prepared with standard substances serve as a standard series with consistent matrix. The standard curve is plotted using the empirical coefficient method, showing good linearity.

The invention relates to a preparation method of ultrathin two-dimensional cobalt oxide rich in oxygen vacancies and an application of the ultrathin two-dimensional cobalt oxide rich in oxygen vacancies in food total antioxidant capacity detection, and belongs to the fields of low-dimensional nano materials, biological mimic enzyme catalysis and analytical chemistry. According to the preparation method, cobalt acetylacetonate and hexadecyl trimethyl ammonium bromide are adopted as raw materials, and the ultrathin two-dimensional cobalt oxide nano-enzyme rich in oxygen vacancies is prepared through a hydrothermal reaction and high-temperature pyrolysis. The obtained ultrathin two-dimensional cobalt oxide nano-enzyme rich in oxygen vacancies has excellent peroxidase-like catalytic activity and selectivity. The oxygen-vacancy-rich metal oxide has the advantages of high stability, easy mass production and low preparation cost, and is expected to be widely used in the fields of biosensing, agriculture, food engineering, catalysis and the like.

The invention belongs to the technical field of analytical chemistry, and discloses a method for detecting creatinine in a creatine product, which comprises the following steps: (1) precisely weighing a sample, adding a buffer solution, carrying out vortex oscillation dissolution, volume metering, shaking up, centrifuging, and passing through a water phase filter membrane to obtain a creatine test solution; (2) a creatine test solution is taken, a liquid chromatograph is adopted for liquid phase detection, and the liquid chromatography conditions are as follows: an SCX chromatographic column is adopted, an ammonium dihydrogen phosphate solution is taken as a mobile phase for isocratic elution, an ultraviolet detector is adopted, and the content of creatinine is obtained according to a liquid phase detection result. According to the method, the situation that the detection result of the creatinine in the creatine product is virtually high can be remarkably reduced, accurate quantification of the creatinine byproduct creatinine is achieved, and a more perfect data basis is provided for quality control of the creatine product.

The application belongs to the field of analytical chemistry detection, and particularly relates to a method for detecting radiochemical purity of an actinium 225 Ac] conjugate. The method adopts high performance liquid chromatography combined with a gamma counter, a mobile phase includes mobile phase A and mobile phase B, the mobile phase A is a mixed solution of buffer salt and cationic pair reagent, and the mobile phase B is acetonitrile. 225 The detection method can accurately detect the radiochemical purity of the actinium 225 Ac] conjugate, is stable and reliable, has high sensitivity, and is of great significance for quality control and research of the actinium [Ac] conjugate product.

The invention relates to the technical field of analytical chemistry sample pretreatment, in particular to an efficient sample injection system for improving liquid sample injection efficiency. Comprising an injection pump, an enrichment cavity, an organic filter membrane, a closed heating pipe and a capillary tube, the organic filter membrane is arranged in the enrichment cavity and divides the enrichment cavity into a chamber I and a chamber II, the injection pump injects a liquid sample into the chamber I through a first pipeline, and the liquid sample is enriched in the chamber II through the organic filter membrane; the chamber II is sequentially connected with a closed heating tube and a capillary tube through a second pipeline, an outlet of the capillary tube is connected with a time-of-flight mass spectrum, the chamber II injects purging gas through a first purging gas pipeline, an enriched sample in the chamber II is purged into the closed heating tube to be gasified and heated, and then the enriched sample is introduced into the time-of-flight mass spectrum through the capillary tube to be analyzed. The device has the characteristics of compact structure, high integration level and high enrichment and gasification efficiency, realizes efficient conversion and sample introduction from a liquid sample to gas, and remarkably improves the sensitivity and efficiency of mass spectrometry.