123 results about "Stable nuclide" patented technology

The invention discloses a water pollution cross-domain traceability method based on multi-chain collaboration and stable isotope source analysis, and relates to the technical field of water environment monitoring, the method comprises the following steps: pollution source chemical fingerprint construction: collecting an environmental water sample and a potential pollution source sample in a drainage basin; adopting a mass spectrometer to detect stable isotope compositions such as delta 13C, delta 15N, delta 18O and the like in the pollutants; and performing morphological division on the pollutants by using a morphological grading extraction technology. Homology judgment precision is greatly improved through isotope and morphological analysis; cross-chain credible collaboration is achieved, multi-party data interaction is achieved, and timeliness and accuracy of pollution tracing are guaranteed; the space-time model traceability is combined with an evolution path and gridding mapping, so that the pollution inversion accuracy is improved; and ecological compensation support provides a quantitative basis for pollution intensity and diffusion range so as to support a compensation model.

The invention provides an article adulteration detection method and system based on stable isotope and electronic equipment, and relates to the technical field of food analysis and detection.The method comprises the steps that a target sample and a control sample of an article to be detected are obtained, and article quality pretreatment is conducted on the target sample and the control sample; carrying out doped sample merging on the target sample and the contrast sample after article quality pretreatment to obtain a doped sample to be detected; wherein the doping sample combination type comprises combination of the same total amount and different proportions and combination of the same proportion and different total amount; performing identification pretreatment on the to-be-detected doped samples, and performing isotope determination on the to-be-detected doped samples subjected to identification pretreatment to obtain various isotope values of specified types corresponding to different to-be-detected doped samples; and performing principal component analysis and / or clustering analysis on the various isotope values of the specified type based on the doping sample combination type to obtain an article adulteration result. According to the invention, the accuracy of article adulteration detection is improved.

The invention provides a detection method of a monomer nitrogen-hydrogen-chlorine multidimensional stable isotope of chloroaniline and a monitoring method of chloroaniline, and relates to the technical field of isotope detection. According to the method, a gas phase-double oxidation tube-stable isotope ratio mass spectrum is adopted to detect and calculate a nitrogen stable isotope ratio in chloroaniline, and a gas phase-chromium filler cracking tube-stable isotope ratio mass spectrum is adopted to detect and calculate a hydrogen stable isotope ratio; the gas phase-multi-collector inductively coupled plasma mass spectrometry is adopted to detect and calculate the chlorine stable isotope ratio, so that the determination of the multi-element stable isotope ratio of nitrogen, hydrogen and chlorine in o-chloroaniline, m-chloroaniline and parachloroaniline is realized, the detection degree is more comprehensive, and the detection result is accurate, efficient and reliable. The range of each isotope signal value in the detection process is controlled, and high accuracy of the detection result can be ensured. The detection method provided by the invention provides a new method and means for deep research and monitoring of chloroaniline traceability, degradation mechanism and environmental homing.

The invention belongs to the technical field of isotope separation, discloses a device and a method for preparing oxygen 18 and heavy water by using tap water, overcomes the defect of high energy consumption caused by a water rectification method, reduces the production cost, and is suitable for production of nuclear power and civil stable isotope oxygen 18 and heavy water. The device comprises a first large tower, a second large tower, a first tower group, a second tower group, a sixth small tower, a seventh small tower and an eighth small tower which are sequentially connected in series, the first large tower and the second large tower are used for pre-concentrating large-flow tap water entering the towers, and an intermediate material obtained at the bottoms of the towers is conveyed to the first tower group and the second tower group through a pump for moderate concentration; tower bottom concentrate is conveyed to the next-stage rectifying tower to be highly concentrated. According to the method, pre-concentration, primary concentration and concentration enrichment are carried out, intermediate products obtained at the tower bottom converge and enter a next-stage rectifying tower, then high-concentration enrichment is carried out, and finally oxy-18 water and heavy water are obtained.

The present invention provides a pretreatment method for determining the stable isotope ratio of non-exchangeable hydrogen in acetic acid, belonging to the field of stable isotope analysis of foods. The pretreatment method comprises the following steps: adding a reaction reagent to a vinegar sample extract to replace the carboxyl hydrogen in the acetic acid with the exchangeable hydrogen to achieve isotope exchange equilibrium. The present invention can be used to simply and rapidly determine the isotope ratio of non-exchangeable hydrogen in acetic acid in vinegar products and can be used in research and applications for detecting the authenticity or adulteration of vinegar products.

The invention discloses a method for enriching < 7 > Li through electrodialysis coupling extraction, which comprises the following steps of: connecting a plurality of functional membranes in series and coupling for enriching < 7 > Li through electrodialysis, respectively placing a supply phase and a receiving phase on two sides of the functional membranes, and adjusting the volume ratio of the supply phase to the receiving phase to be (1-100): (1-100) by controlling the flow rates of the supply phase and the receiving phase through PID (Proportion Integration Differentiation), and electrifying the electrodes on the two sides of the plurality of functional membranes which are connected in series, applying voltage with the voltage of-20 to 20V for 3 seconds to 120 minutes, and extracting and separating the Li isotope. According to the method, the Li isotope is subjected to cascade separation through an electrodialysis coupling membrane technology, so that the selectivity of 7Li is increased, the separation and enrichment effect of the 7Li isotope is improved, and the abundance of the 7Li natural stable isotope can be improved from 92.47% to 5N level through 102-level cascade.

The invention relates to the technical field of biochemical detection and analysis, in particular to a method for screening halogenated carbazole active degrading bacteria based on a single-cell Raman spectrum technology, which utilizes the characteristic of more active substance exchange between high-activity microorganisms and the outside, adopts a stable isotope probe to anchor active strains, and performs targeted screening to obtain the halogenated carbazole active degrading bacteria. Therefore, the degrading bacteria are firstly screened and then cultured. Compared with other markers (13C and 15N), the deuterium (2D) marker is lower in price, and an obvious C-D tensile vibration band can be observed in a Raman silence region. According to the method, the time for screening the functional strain is shortened to several days from several months in the prior art, the performance of the active functional strain is improved by multiple times compared with that of the strain obtained through a traditional method, and the technical bottleneck that the single-active strain is difficult to effectively obtain through the traditional method is broken through.

The invention discloses a terrestrial ecosystem water vapor flux stable isotope multi-source estimation method, which comprises the following steps: collecting monitoring data and environmental data of a preset area, and preprocessing the monitoring data and the environmental data; performing water vapor motion characteristic analysis on the monitoring data according to a stable isotope to obtain division data, and inputting the division data into a stable isotope model to obtain water vapor flux; performing time-varying influence analysis on environmental data according to the water vapor flux to obtain an influence factor, and constructing a terrestrial ecosystem water vapor flux multi-source estimation model according to the influence factor and the monitoring data; and optimizing the terrestrial ecosystem water vapor flux multi-source estimation model, inputting to-be-estimated data into the terrestrial ecosystem water vapor flux multi-source estimation model, and outputting an estimation result. The method not only can improve the multi-source estimation precision of the water vapor flux of the terrestrial ecosystem, but also has good interpretability, and can be directly applied to a water vapor flux multi-source estimation system.

The invention discloses a method for determining carbon isotopes of low-concentration soluble organic carbon in a water body, and belongs to the technical field of organic carbon detection. The determination method comprises the following steps: combining a TOC analyzer and a stable isotope mass spectrometer, and converting DOC in a water body into CO2 gas by adopting the TOC analyzer; cO2 gas generated by the TOC analyzer is enriched for the first time through the cold trap T1; the CO2 gas frozen by the cold trap T1 is enriched for the second time through a cold trap T2; introducing the CO2 subjected to secondary enrichment into a stable isotope mass spectrometer, and determining the carbon isotope composition of the CO2. Aiming at a low-concentration DOC water body, the carbon isotope composition of DOC in the water body is determined on the basis of combination of a wet oxidation technology and stable isotope mass spectrometry detection, a wet oxidation method is used for increasing the volume of a water sample to generate more CO2 for stable isotope mass spectrometry determination, so that more accurate carbon isotope composition is obtained, and the method is efficient, time-saving, labor-saving and accurate.

The invention belongs to the technical field of rainwater treatment, discloses a method for evaluating the water holding capacity of a bioretention facility, and aims to effectively evaluate the water holding capacity of the bioretention facility and provide scientific guidance for subsequent construction of the bioretention facility. According to the scheme, the method comprises the following steps: collecting a soil water sample and a rainfall inflow water sample of the bioretention facility; the outflow flow of the bioretention facility in the rainfall event is continuously monitored, and outflow water samples in different time periods are collected; respectively carrying out oxyhydrogen stable isotope detection analysis on the collected soil water sample, the rainfall inflow water sample and the outflow water samples in different time periods; respectively calculating the soil moisture in the effluent water sample at different time periods and the composition proportion of the rainfall inflow water component according to the detection analysis result, and dividing the soil moisture outflow process from the outflow flow; and evaluating the water holding capacity of the bioretention facility according to the soil moisture outflow process.

The invention discloses a mine water source identification method, system, equipment and medium based on a combined weight and grey relational degree theory, and relates to the technical field of mine water source identification, and the method comprises the steps: obtaining water quality parameters and stable isotope composition of a mine water sample, and building a comprehensive feature matrix; calculating the correlation degree between each water quality parameter and a preset water source type based on the comprehensive feature matrix, analyzing the composition and proportion of multi-source water mixing in the mine water sample, and determining a first mine water source identification result; and weighting the water quality parameters and the stable isotope composition in the comprehensive characteristic matrix by using a combined weight method, and obtaining a second mine water source identification result based on the weighted comprehensive characteristic matrix and the first mine water source identification result. The method has high prediction speed and prediction precision, the existence condition of the underground water source can be identified by using a geophysical prospecting method according to different geological conditions through the prediction model, and the acquisition process of the underground water burst source is more convenient.

The utility model relates to the technical field of gas transfer, and provides a sample introduction device for gas stable isotope value measurement, which comprises a containing tank with a containing space and a plurality of communicating pipes communicated with the containing space; the high-concentration gas injection pipe is arranged on the containing tank and communicated with the containing space, and high-concentration detection gas can enter the containing space through the high-concentration gas injection pipe. By means of the technical scheme, the technical problems that when a gas pre-concentration device is used in the prior art, gas cannot be directly supplied for high-concentration gas, the high-concentration gas can only be detected after being diluted in advance, the detection cost is increased, and the detection result has errors are solved.

The object of the present invention is to provide a stable isotope enrichment method that can reduce equipment costs and power without lengthening the start-up time and can achieve efficient enrichment. The present invention provides a stable isotope enrichment method, which is a method for separating stable isotopes using a plurality of distillation columns (the first column to the m-th column; m is an integer of 2 or more) connected in cascade. One of gas and liquid is supplied from a position near the bottom of the (n-1)-th column to a position near the top of the n-th column (1 < n ≤ m), and the other of gas and liquid is returned from a position near the top of the n-th column to a position near the bottom of the (n-1)-th column. In each distillation column, when the flow rate of the gas rising in the column is set as the first flow rate and the flow rate of the gas or liquid supplied from the previous column or the next column is set as the second flow rate, the second flow rate is set to 4% by volume or more of the first flow rate.

The invention relates to the technical field of metallurgy, and discloses an intelligent steelmaking process based on dynamic raw material proportioning, the core of the process is that a functional pellet with a core-shell-film multilayer structure is adopted, functional components sequentially acting in a molten pool are packaged in different layers of the functional pellet respectively, and the functional components are sequentially separated from the molten pool. The stable isotope tracers are in one-to-one correspondence with the functional components and can be released in sequence. A mass spectrometer sensing system is used for detecting specific time sequence signals formed by sequential release of the tracer agents on line, and the system can confirm the delivery and step-by-step reaction process of materials and conduct on-line self-correction on kinetic parameters in a metallurgical process model. According to the method, a closed-loop control system integrating precise feeding, process confirmation and model adaptive capacity is constructed, and adaptive control over the steelmaking process is achieved. The method can improve the control precision of molten steel components and temperature at the smelting end point, shorten the smelting period, and improve the overall production efficiency and the resource utilization rate.

The invention relates to the technical field of stable isotope tracing, and particularly discloses a temperature and humidity control 13C continuous stable isotope labeling device and method.The temperature and humidity control 13C continuous stable isotope labeling device comprises a labeling chamber, a concentration control assembly is arranged on one side of the labeling chamber, and a concentration monitoring assembly is arranged on one side of the concentration control assembly; a humidification assembly is arranged on the side, away from the concentration control assembly, of the concentration monitoring assembly, a dehumidification assembly is arranged on the side, away from the concentration monitoring assembly, of the humidification assembly, and an air pressure balance assembly is arranged on the side, away from the humidification assembly, of the dehumidification assembly. According to the device, accurate comprehensive regulation and control of multiple environmental factors such as gas concentration, temperature, humidity and air pressure in the device are realized, an ideal and accurate experimental environment is created for researching interaction of a plant-soil system under different environmental conditions, and the problems of poor temperature and humidity regulation effect and the like in the prior art are effectively solved.

The present application relates to a kind of detection methods of isotopic abundance in acetic acid, comprising the following steps: stable isotope labeled acetic acid is decomposed under vacuum and high temperature conditions, generates stable isotope labeled methane or carbon dioxide, can determine 13 C labeled in carboxyl site acetic acid CH3 13 COOH in 13 C isotopic abundance, 13 C labeled in methyl site acetic acid 13 CH3COOH in 13 C isotopic abundance, 18 O labeled acetic acid CH3C 18 O 18 OH in 18 O isotopic abundance, methyl deuterium isotopic abundance in deuterium labeled methyl site acetic acid CD3COOH;Compared with prior art, the present application has the advantages that the isotopic abundance in acetic acid labeled by stable isotope in different sites is detected, can be used for deuterium, 13 C or 18 O labeled acetic acid isotopic abundance determination, test data accuracy and precision etc.

The invention provides a medicine raw material homology judgment method and device, computer equipment and a medium, and belongs to the field of medicine identification, and the method comprises the following steps: obtaining a plurality of same sample medicines from different sources; determining the stable isotope abundance values of carbon, nitrogen, oxygen and hydrogen in the drug sample through a stable isotope ratio mass spectrometry and a chromium-assisted stable isotope ratio mass spectrometry; taking the stable isotope abundance value as a variable, and classifying sample drug sources by adopting a hierarchical clustering analysis and principal component analysis method to obtain a plurality of drug sources; obtaining stable isotope abundance values of to-be-classified target drugs, and respectively determining the stable isotope abundance values of the target drugs and Z values of the stable isotope abundance values of all classes based on a Z value analysis method; under the condition that the Z values of the stable isotope abundance values of all the elements are smaller than or equal to the preset threshold value, it is determined that the target drug and the sample drug of the corresponding category are homologous drugs, and therefore the accuracy of drug detection is improved.

The invention relates to a sulfur isotope detection device system and method for organic sulfides in natural gas, impurities in the natural gas are removed through a preset chemical trap and a hydrogen sulfide adsorption trap coupled with a heating device for use, and the effective enrichment space of the organic sulfides in a cold trap is prevented from being occupied; two stages of cold traps are adopted, so that organic sulfides can be effectively enriched and detected and analyzed; the sulfur isotope detection device system is high in reliability, high in automation degree and easy to operate, sulfur isotope detection and analysis are carried out by combining a chromatography-stable isotope mass spectrometer, and a new way is provided for researching causes, sources and generation mechanisms of sulfur-containing natural gas.

The embodiment of the application provides a marine carbonate high-resolution sequence stratigraphic division method and device, and belongs to the technical field of geological exploration. The method comprises the following steps: obtaining logging data of a target well section, generating a first curve based on the logging data, the first curve being a curve for representing the rise and fall of the paleo-sea level of the target well section; obtaining stable isotope data of the target well section, correcting the first curve based on the stable isotope data, obtaining a second curve, and thus establishing a high-resolution sequence division scheme of a single well; obtaining a seismic profile of the target well section, determining a negative inflection point of the second curve, and calibrating the seismic profile based on different levels of the negative inflection point of the second curve, so as to determine a high-resolution sequence tracking scheme of the target well section; and the application can quickly and conveniently solve the problem of high-resolution sequence stratigraphic division and comparison.

The application relates to the technical field of plasma, in particular to a medical cyclotron beam centering adjustment method and system. The method comprises the following steps: acquiring a magnetic field sequence, a beam sequence and a current sequence; obtaining a beam fluctuation factor according to the difference in lag number corresponding to the maximum autocorrelation coefficient of the magnetic field sequence and the beam sequence, the correlation of the magnetic field sequence and the beam sequence, and the difference in the maximum autocorrelation coefficient; forming a beam fluctuation sequence by using the beam fluctuation factor; dividing the beam fluctuation sequence, and also dividing the current sequence; fitting a straight line based on the current fluctuation sequence and the current sequence; obtaining the current influence intensity at the current moment according to the difference between the excitation current in all sub-sequences and the overall excitation current of the current sequence and the mean square error; improving the proportional term according to the current influence intensity, controlling the excitation current based on the proportional term, and adjusting the proportional term in real time to optimize the magnetic field control effect. The application realizes higher and more stable nuclide production efficiency.

The invention discloses a method for high-precision detection of carbon stable isotope and content thereof in an environmental sample. The method provided by the invention comprises the following steps: detecting environmental sample powder by using an elemental analysis-stable isotope mass spectrometer; the sampling amount of the environmental sample powder is greater than or equal to 0.4 mg; in the detection process, inert gas is introduced into an opening flow divider in a Conflo universal interface of the elemental analysis-stable isotope mass spectrometer, and the inert gas is mixed with sample gas obtained by combustion in an elemental analyzer. According to the method provided by the invention, the situation that a sample signal is too high and exceeds a linear range is avoided, the representativeness of the sample is improved, the possibility of data abnormity caused by nonuniformity of the sample is reduced, and the aim of rapidly and accurately detecting the stable carbon isotope and the content of the stable carbon isotope at the same time is fulfilled.

The present invention belongs to the technical field of gas stable isotope determination, and provides 15 A pretreatment system and method for gas products of N tracer nitrification-denitrification. The pretreatment system of the present invention uses a chemical trap to remove CO2 and H2O from the gas products of nitrification-denitrification; the first cold trap can remove CO2, H2O, NH3, NO2 and N2O from the gas products of nitrification-denitrification; the oxygen is removed by using a high-temperature reduction furnace; then the trace carbon monoxide, small molecule organic matter and nitrogen are separated by using a separation column; and the residual CO2, H2O, NH3, NO2 and N2O are removed by using a second cold trap. The pretreatment system of the present invention can remove O2, NOx, CO2, H2O and small molecule organic matter from the gas products of nitrification-denitrification, which is beneficial to the accurate detection of N2 in the gas products of nitrification-denitrification.

The present invention proposes a method for determining the stable isotope ratio of non-exchangeable hydrogen sites of glycerol in edible oils and fats, belonging to the field of stable isotope analysis technology. The method comprises the following steps: a) preparing a preliminary glycerol sample; b) determining the stable hydrogen isotope ratio of glycerol in the preliminary glycerol sample using a gas chromatography-pyrolysis-stable isotope ratio mass spectrometer; c) selecting glycerol with a known stable isotope ratio of non-exchangeable hydrogen sites as a working standard substance, processing according to step a), and determining according to step b) to obtain the stable hydrogen isotope ratio of the glycerol working standard substance; and calculating the stable isotope ratio of the non-exchangeable hydrogen sites of glycerol in the edible oil to be tested by comparing the measurement result of the stable hydrogen isotope ratio of the glycerol working standard substance with the known stable isotope ratio of the non-exchangeable hydrogen sites of the glycerol working standard substance. The method is rapid and accurate, providing a new analytical method for adulteration detection and authenticity control of oils and fats.

The present invention relates to a 13 C. 18 The synthesis method of trifluoroacetic acid with O stable isotope double labeling is as follows: firstly, trifluoroacetic acid is dissolved in a solvent, metal ions are added, and 13 C-labeled carbon dioxide, react to obtain a reaction solution, then separate and dry the reaction solution to obtain 13 C-enriched trifluoroacetic acid, and finally 13 C-enriched trifluoroacetic acid is dissolved in an aprotic solvent, thionyl chloride is added, stirred for reaction, and then a catalyst and oxygen 18 water are added, heated for reaction, and the reaction product is separated to obtain 13 C. 18 O stable isotope double labeled trifluoroacetic acid is the target product. Compared with the prior art, the present invention has a simple reaction process, a simple post-processing process, and a high yield. 13 The C isotope abundance is over 98%. 18 The O isotope abundance is over 97%.

The invention relates to the technical field of stable isotope electromagnetic separation systems, in particular to a high-voltage exercise ignition protection method and device and a stable isotope electromagnetic separation system. The high-voltage exercise ignition protection method comprises the following steps: detecting ignition signal intensity and ignition time of an ion source; when the ignition signal intensity is larger than a first threshold value, if the ignition time is larger than first preset time, the high-voltage power source is turned off, and slow starting is conducted; if the ignition time is smaller than the first preset time, high-voltage exercise continues to be carried out; when the ignition signal intensity is larger than a second threshold but smaller than the first threshold, if the ignition time is larger than second preset time, the high-voltage power supply is turned off, and quick starting is carried out; if the ignition time is smaller than the second preset time, high-voltage exercise continues to be carried out; and when the ignition signal intensity is smaller than a second threshold value, high-voltage exercise continues to be carried out. By means of the method, some sparking phenomena which cannot damage components can be ignored, and the problem of excessive protection caused by frequent restart of the high-voltage power supply system is avoided.

The utility model discloses a deashing device for an oxidation-reduction reaction tube, which comprises a bracket, a deashing device, a deashing device and a control device, wherein the bracket is provided with a fixing piece for vertically fixing the oxidation-reduction reaction tube to be dedusted; the driving rod can be inserted into the reaction tube to be dedusted, and can rotate and move up and down in the reaction tube; the upper end of the ash removal disc is fixedly connected with the lower end of the driving rod, and a plurality of ash removal teeth are arranged at the lower end; and the driving device is in transmission connection with the upper end of the driving rod and is used for driving the driving rod to rotate and move up and down. According to the deashing device for the oxidation-reduction reaction tube of the stable isotope mass spectrometer, ash attached to the inner wall of the reaction tube is ground off through the deashing teeth at the lower end of the deashing disc, efficient and automatic deashing of the reaction tube is achieved, and the labor intensity of an operator is greatly reduced.

The present invention belongs to the technical field of determination of gaseous hydrocarbon hydrogen isotope composition in mineral inclusions, and specifically discloses a device and method for extracting gaseous hydrocarbon hydrogen isotope composition in mineral inclusions. The present invention adopts helium as the protective carrier gas of the online continuous flow system, and each helium uses a water trap filled with magnesium perchlorate to absorb and dry the trace water that may exist in the helium, so as to avoid the influence of the trace water in the carrier gas on the test results of the gaseous hydrocarbon hydrogen isotope composition. The present invention adopts an online continuous flow method to connect the mineral inclusion explosion device, methane oxidation, and product water collection device with a stable isotope mass spectrometer, so as to realize the online heating explosion of the mineral in the helium flow environment, the online oxidation of methane, the online collection of the oxidation product water, and the electric heating and release of water into the stable isotope mass spectrometer for testing. Compared with the traditional offline method, the sample amount is greatly reduced, thereby effectively reducing the workload of mineral processing and the scientific research cost, and improving the scientific research efficiency.

The invention relates to the technical field of detection, and discloses a method for tracing the origin of silkworm cocoons based on a stable isotope technology in combination with a machine learning algorithm, and the method comprises the steps: (1) collecting data; (2) data preprocessing; (3) model optimization; (4) model training; and (5) producing area tracing. According to the invention, origin traceability of silkworm cocoons from different origins is realized based on isotope analysis and a machine learning algorithm. Specifically, hydrogen, oxygen, carbon and nitrogen stable isotope ratio data are combined with KNN, SVM and RF algorithms to realize rapid and high-precision source tracing of silkworm cocoon producing areas. According to the invention, by combining the advantages of various machine learning algorithms, the accuracy and reliability of silkworm cocoon origin tracing are improved.

The invention provides an experimental method for determining stable carbon and oxygen isotopes by a two-way sampling method, and relates to the technical field of stable isotope analysis. The experimental method comprises the following steps: selecting carbon dioxide gas with the purity of more than 99.999% as carbon dioxide reference gas, and selecting a calcium carbonate carbon and oxygen isotope standard substance and a target sample to be measured; and then the stable carbon and oxygen isotopes are determined through a two-way sample introduction method, standard gas does not need to be purchased, the isotope ratio of a sample relative to a standard substance is obtained through conversion application of a formula, finally, the isotope ratio is successfully calibrated to the value of international standard PDB, and the experiment cost is saved. The method can be widely applied to other stable isotope two-way sample introduction methods, principle communication is achieved, and determination can be conducted through the experimental method under the condition that no standard gas exists.

The present invention belongs to the technical field of determination of carbon isotope composition of methane in gas, and specifically discloses an online continuous flow extraction device for methane in gas and a carbon isotope composition analysis method, the device comprises a first six-way valve, a plurality of helium inlets connected to the first six-way valve, a second six-way valve connected to the first six-way valve, a helium inlet connected to the second six-way valve, a carbon dioxide collection pipe connected to the second six-way valve, a single-opening quartz tube connected to the second six-way valve, and a stable isotope mass spectrometer connected to the second six-way valve, the method is as follows: step 1, gas sample loading; step 2, back-blowing to degas, exhaust the air in the pipes at both ends of the gas collection pipe; step 3, oxidation, purification and collection of methane in the gas; step 4, carbon dioxide sublimation injection; step 5, methane carbon isotope determination. The present invention solves the problems of excessive consumption of sample preparation gas for offline pretreatment, cumbersome operation process and low efficiency.