162 results about "Isotope analysis" patented technology

The invention discloses a river nitrogen pollutant source analysis method based on drainage basin nitrogen turnover and isotope, and particularly relates to the technical field of water treatment.The river nitrogen pollutant source analysis method comprises the following steps that a drainage basin to be researched is selected, river water and soil samples in the drainage basin are systematically collected, and physical and chemical indexes and isotope indexes # imgabs0 # of the collected samples are tested. Nitrate marked by nitrogen isotope delta 15N / delta 18O and # imgabs1 # are used as key indication marks to perform high-precision identification on nitrogen sources in a river and an environmental system, the contribution proportion of different nitrogen sources to the nitrate concentration in a water body is quantified through a stable isotope analysis model, and the concentration of the nitrate in the water body is calculated. And in combination with data, the rates of denitrification and anaerobic ammonia oxidation in environmental samples, sediments and soil are directly measured through combined application of an isotopic tracer technology and a membrane inlet mass spectrometer technology.

The invention relates to an isotope-based underground water organic pollution traceability analysis method and system. The method comprises the following steps: collecting pollutant parameters of a monitoring point at a plurality of time intervals; constructing a target monitoring point set; the coverage area is called as a target area; discovering and analyzing pollutant parameters of each monitoring point in the target monitoring point set based on the typical time interval so as to obtain contour lines corresponding to pollutant parameter types; taking an area in the contour line corresponding to the high pollutant parameter of each pollutant type as a suspected area; and determining a target pollution source in the suspected area based on the isotope parameters. According to the method, big data monitoring resources are fully utilized in space and time, pollutant parameters are combined, isotope analysis resources are optimized and utilized, pollution sources are tracked and guided, and efficient multi-source burst differentiated pollutant traceability is provided.

The invention discloses a method for accurately deducting Sr double-charge interference in in-situ Ca isotope determination, and relates to the technical field of isotope analysis. According to the method, the Sr double-charge interference in the in-situ Ca isotope measurement is accurately deducted through an iteration method, the Ca isotope measurement result can be simply and quickly corrected, and high-resolution, low-detection-limit and high-flux Ca isotope measurement is realized; ca single-charge fractionation factors are calculated through an iterative method, and instrument quality discrimination correction and accurate deduction of Sr double-charge interference are simultaneously realized through formulas 1-5 in combination with the Sr isotope ratio; the method breaks through the application limitation of in-situ Ca isotope measurement, is suitable for high-Sr and low-Sr samples, solves the technical problems of in-situ Ca isotope analysis accuracy and analysis precision, fills the technical blank of Ca isotope measurement in the Sr-rich sample in laser in-situ detection, and provides a firm technical support for application in the field of geoscience.

The utility model belongs to earth and planet chemical instrument equipment, and discloses a Nano-C isotope analysis device which comprises an element analysis system, a carbon dioxide freezing enrichment system and an isotope mass spectrometry system, the carbon dioxide freezing enrichment system comprises a six-way valve, the six-way valve is communicated with a first freezing assembly and a second freezing assembly, and the second freezing assembly is communicated with the isotope mass spectrometry system; the first freezing assembly comprises a first freezing container, and a first cold trap communicating with the six-way valve is arranged in the first freezing container in a liftable mode. The second freezing assembly comprises a second freezing container, and a second cold trap communicating with the six-way valve is arranged in the second freezing container in a liftable mode. The carbon isotope analyzer is simple and compact in mechanism, convenient to use, capable of analyzing carbon elements in different forms and accurately measuring isotope composition of carbon in different forms at the nanomole level, capable of enriching and purifying a sample to be detected for multiple times, capable of reducing analysis errors and capable of improving measurement sensitivity and precision.

The invention relates to the technical field of intelligent collection of rainfall samples, in particular to an intelligent collection system for rainfall isotope samples, which comprises an environment monitoring module, a sampling equipment control module, a sampling data acquisition module and a sampling data verification module, the wind direction and meteorological data of a deployment area are obtained, the opening and closing speed of a cover body of a sampling device is dynamically calculated, synchronous control is executed, and a chromaticity response curve and a flow response curve are constructed by combining high-frequency collection and delay correction of filtrate flow and chromaticity; extracting chromaticity mutation points through sliding window extreme value detection and threshold value comparison, and judging that the quality of the filtrate is abnormal; and on the basis of symmetric compensation and curve similarity evaluation, cover body opening and closing faults are identified, and dual verification of physical structure abnormity and sampling data validity in the sampling process is realized. The system can improve the representativeness and accuracy of the rainfall sample in a complex meteorological environment so as to ensure the stability and traceability of a subsequent isotope analysis result.

The invention discloses a plain small watershed nitrogen and phosphorus pollutant collaborative source analysis method, which belongs to the technical field of environmental pollution traceability, and comprises the following steps: 1, collecting multi-source basic data in a target plain small watershed, carrying out unified coordinate system, format and precision preprocessing, and constructing a watershed basic database; and 2, constructing a response relation model of various pollution sources and potential pollution loads on a GIS platform based on a drainage basin basic database, qualitatively identifying main pollution sources through spatial visualization analysis, and delineating key risk areas. According to the method, macroscopic spatial analysis, microchemical tracing and mathematical model calculation are organically fused, high-precision spatial data, hydrochemical and isotope analysis, multi-model quantitative analysis and uncertainty quantification are integrated, and high-precision and high-reliability cooperative source analysis of nitrogen and phosphorus pollutants is achieved.

The invention discloses an ultratrace mercury isotope analysis method, and relates to the technical field of environmental analysis. The method comprises the following steps: purging a liquid sample to be detected by nitrogen in a stannous chloride atmosphere, and trapping and concentrating mercury into a gold trapping tube; pyrolyzing the pyrolytic gold trapping tube to release mercury vapor; pyrolytic mercury vapor and thallium isotope internal standard aerosol are mixed to serve as a sample injection sample, and the sample injection sample is introduced into a multi-receiver inductively coupled plasma mass spectrometry; acquiring a mercury instantaneous signal and a thallium isotope signal; and calculating the mercury isotope ratio by adopting least square linear regression fitting in combination with a thallium internal standard ratio correction algorithm. According to the method, the instantaneous mercury isotope signal is generated by online combination of gold trapping and multi-receiver inductively coupled plasma mass spectrometry, the instantaneous signal is strategically collected and processed, the determination concentration of isotope analysis can be greatly reduced, the sensitivity of the method is remarkably improved, and direct determination of mercury isotope composition in a water sample with the concentration of 10 ng L <-1 > is met.

The invention discloses a fluid inclusion standard sample for in-situ isotope analysis as well as preparation and application of the fluid inclusion standard sample. The preparation method comprises the following steps: obtaining silicate glass powder with uniform components, carrying out high-temperature and high-pressure reaction on the glass powder and a fluid salt solution with the same mass in a closed Cu-Au tube, taking out a reaction product after the reaction, and drying to obtain the fluid inclusion standard sample for isotope analysis. According to the method, the silicate glass with uniform components can rapidly capture the fluid inclusion, and the Cu isotope in the fluid inclusion is accurately measured and controlled according to the fractionation degree of the Cu isotope between the acid salt melt and the fluid.

The invention discloses a device and a detection method for online oxidation-enrichment-reduction determination of nanogram-level nitrogen isotopes in a solid, and belongs to the technical field of nitrogen isotope analysis. The device comprises an oxidation system, a nitrogen oxide enrichment system, a nitrogen reduction system, a mass spectrum interface system, a stable isotope ratio mass spectrometer and pipelines for connecting all parts of the device. The device provided by the invention greatly reduces the quantitation limit of the nitrogen isotope in the solid sample, can realize high-precision determination of the nanogram-level nitrogen isotope in the solid sample, and has the advantages of simplicity and convenience in operation, high accuracy and the like.

The invention belongs to the technical field of isotope analysis, and particularly relates to a data correction method for measuring hydrogen and oxygen isotope components of plant water. The data correction method for measuring the hydrogen and oxygen isotope components of the plant water comprises the following steps: performing isotope spectrum measurement on the plant water to be measured to obtain delta18O plant water, delta2H plant water and residual R plant water; obtaining the corrected delta18O plant water in the to-be-detected plant water according to the correction curve formula 1; obtaining the corrected delta2H plant water in the plant water to be detected according to the correction curve formula 2; delta < 18 > O plant water correction = delta < 18 > O plant water-Y1 formula 1; delta 2H plant water correction = delta 2H plant water-Y2 formula 2. The correction method provided by the invention is simple to use, is widely applicable to the process of measuring the hydrogen and oxygen isotope component in the plant water by an isotope spectrometer, and can greatly improve the accuracy of a measurement result.

The invention discloses a coal mine natural fire prediction and alarm method based on a CO isotope database, and relates to the technical field of coal mine fireproof safety. S1, sample collection; s2, temperature programming; s3, isotope analysis; s4, constructing a database; and S5, real-time monitoring. Gas samples at specific positions under a coal mine are collected in real time, CO isotope composition of the gas samples is analyzed, data are input into an established database model, the occurrence probability and the development trend of the natural fire of the coal mine are rapidly and accurately predicted through comparative analysis, and an alarm signal is sent out in time when a preset danger threshold value is reached. Scientific basis and sufficient response time are provided for coal mine disaster prevention and control.

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 belongs to the technical field of chemical detection, and particularly relates to a Raman-LIBS-mass spectrometry combined analysis device and analysis method.The Raman-LIBS-mass spectrometry combined analysis device comprises a multiple reflection time-of-flight mass spectrometer, an LIBS spectrometer, a Raman spectrometer and a common module; the common module comprises a first incident light path system, a second incident light path system, a high-definition observation system, a vacuum sample bin, a vacuum system and a control system; the first incident light path system is used for generating a femtosecond laser beam and performing three-dimensional denudation on a sample; and the second incident light path system is used for combining the tunable laser into a resonant ionization light path. Compared with the prior art, in-situ micro-area ultrahigh-resolution element and isotope analysis and imaging can be achieved, ultra-trace element and isotope analysis and isotope ratio analysis under strong matrix interference are achieved, and meanwhile high-resolution molecular structure and composition analysis and Raman scattering imaging can be conducted.

The invention discloses a method for accurately measuring a nano ion probe olivine Mg isotope micro-region and applying a moon sample, particularly relates to application of a nano ion probe (SIMS) technology in magnesium isotope analysis, and particularly relates to a method for carrying out high-resolution and high-precision magnesium isotope analysis and on-line matrix effect correction by utilizing a nano ion probe (NanoSIMS). The method comprises the following steps: (1) synthesizing an olivine reference substance with a coverage Fo value (magnesium-iron ratio) range of 0-90 by using a high-temperature and high-pressure experimental method, and verifying composition uniformity and isotope stability of the olivine reference substance through an electron probe (EMPA) and a multi-receiving inductively coupled plasma mass spectrometry (MC-ICP-MS); (2) optimizing NanoSIMS instrument parameters, and realizing synchronous detection of 24Mg < + >, 26Mg < + >, 28Si < + > and 56Fe < + > through a static multi-collection mode; (3) based on the ratio of 24Mg / (24Mg + 56Fe), proposing a biphase Hill equation to correct the matrix effect, and realizing online correction; and (4) analyzing the geological sample by using the method, and revealing the chemical and isotope change characteristics of the micron scale. The method has high resolution (1 [mu] m) and high precision (0.4 per thousand to 0.6 per thousand), and is suitable for micro-area isotope analysis in the fields of planetary science and geochemistry.

The invention relates to a synthetic standard sample suitable for in-situ pyrrhotite Fe-S isotope analysis and a preparation method and application thereof, and belongs to the technical field of geological analysis and material analysis. The particle size of the synthesized standard sample is 100-150 microns, and the interior of the particle is compact and free of holes; delta 34S is equal to-1.16 + / -0.22 per mill, and delta 56Fe is equal to 0.39 + / -0.03 per mill; the delta 34S in the synthesized standard sample is detected by SIMS, and the standard deviation 2SD of the delta 34S is 0.53%. The delta 56Fe in the synthesized standard sample is detected by LA-MC-ICPMS, and the standard deviation 2SD of the delta 56Fe is equal to 0.47 per mill. The method has the advantages that the pyrrhotite is synthesized in a laboratory, the reproducibility of the synthesized standard sample is realized, and the problems that the original in-situ pyrrhotite Fe-S isotope standard sample is natural in source, very few in available quantity and non-reproducible are solved.

The application belongs to the technical field of chemical detection, and particularly relates to a Raman-LIBS-mass spectrometry combined analysis device and analysis method. The Raman-LIBS-mass spectrometry combined analysis device comprises a multiple-reflection time-of-flight mass spectrometer, a LIBS spectrometer, a Raman spectrometer and a shared module. The shared module comprises a first incident light path system, a second incident light path system, a high-definition observation system, a vacuum sample bin, a vacuum system and a control system. The first incident light path system is used for generating a femtosecond laser beam and performing three-dimensional ablation on a sample. The second incident light path system is used for combining tunable lasers into a resonance ionization light path. Compared with the prior art, the application can realize in-situ micro-area ultra-high resolution element and isotope analysis and imaging, realize ultra-trace element, isotope analysis and isotope ratio analysis under strong matrix interference, and can also perform high-resolution molecular structure and composition analysis and Raman scattering imaging.

Collection and separation systems, collection and separation methods, isotope analysis systems, methods of processing samples to analyze 15N, 13C, and 34S, and the like are provided. A system that includes a collection system in gaseous communication with a first device, wherein the collection system is configured to isolate two or more gases of a gaseous sample and configured to introduce each to a second device independently of one another is provided.

The present invention discloses a nitrogen isotope determination method for nitrogen in a gas sample, and relates to the technical field of isotope analysis, the method comprises: instrument performance pretreatment: before sample determination, determining that an instrument is in a stable working state by checking the vacuum degree, detecting the interference peak, tuning an ion source, and testing the stability and linearity of reference gas; according to the method, a glass sample bottle is adopted to collect a gas sample, and before collection, a bidirectional inert gas replacement-vacuumizing coupling sampling process is adopted to treat the sample bottle. Residual air in the sample bottle and air attached to the bottle wall are effectively removed, and the sample pollution risk is remarkably reduced; the CO2 adsorption trap adopts a gradient filling structure and is matched with a constant-temperature heating sleeve, so that the contact time of CO2 and an adsorption material is prolonged, meanwhile, the influence of adsorption heat release on the adsorption efficiency is avoided, and the CO2 removal rate is improved.

The present application relates to a kind of groundwater organic pollution tracing analysis method and system based on isotope, the method comprises: collecting the pollutant parameter of monitoring point in multiple time intervals;Build target monitoring point set;Its coverage area is called target area;Based on typical time interval, the pollutant parameter of each monitoring point in analysis target monitoring point set is found to obtain the contour line corresponding to pollutant parameter type;The area in the contour line of each pollutant type high pollutant parameter is regarded as suspected area;Determine target pollution source in suspected area based on isotope parameter.The present application fully utilizes big data monitoring resources from space and time, combines pollutant parameter itself and optimally uses isotope analysis resources, and the tracking of pollution source is guided to provide efficient multi-source burst differentiating pollutant tracing.

The invention discloses a method for evaluating reservoir quality evolution after sandstone is filled with deep-source CO2, and belongs to the technical field of petroleum exploration. According to the method, the sandstone in the CO2 filling area is selected as a research object, the sandstone in the undisturbed area adjacent to the CO2 filling area is selected as a reference object, the porosity, permeability and pore structure difference of the sandstone reservoirs in the CO2 filling area and the undisturbed area are compared and analyzed, the diagenesis stages, symbiotic sequences and lithologic characteristics of the sandstone in the CO2 filling area and the undisturbed area are determined, and the sandstone in the CO2 filling area and the undisturbed area is determined. Carbon and oxygen isotope analysis is carried out on the carbonate cement, diagenesis fluid evolution characteristics and differences of the sandstone reservoirs in the CO2 filling area and the undisturbed area are compared and analyzed, and finally the reservoir quality evolution process after the sandstone is filled with the CO2 is clarified. According to the evaluation method, the deep CO2 source and the filling time are determined, the change of the mineral composition and the structure of the reservoir caused by CO2 filling is revealed, the mechanism of changing the reservoir quality by CO2 filling is clarified, and the problem that the time sequence of CO2 filling and organic hydrocarbon filling is not clear is solved.

The invention provides a shallow carbon source in-situ biological gasification detection method, which comprises the following steps: analyzing the composition of a gas product of biological gasification, and carrying out isotope characteristic analysis on part of components in the gas product; regularly extracting gas products of biological gasification and carrying out methane cluster isotope analysis; according to the characteristic change of the gas product, the progress condition of shallow carbon source biological gasification and the breeding condition of microbial flora are analyzed. According to the method, the composition and isotope characteristics of gas products in the shallow carbon source biological gasification process are analyzed on line, methane cluster isotope off-line analysis is carried out regularly, and the characteristic change of the biological gasification products is monitored, so that the progress condition of biological gasification is judged, and the active condition of microbial flora is judged; efficient operation of biological gasification is promoted by adjusting environmental conditions; the method is simple, convenient and rapid to operate, real and reliable in judgment result and suitable for research of multiple types of shallow carbon enrichment areas, and a basis is provided for exploration and exploitation.

The present application belongs to the technical field of material testing and analysis, and specifically relates to a system for separating nitrite and nitrate in water samples and a method for determining nitrogen and oxygen isotopes. The separation system includes a connected hanging bottle, a three-way head, a flow rate controller, a resin glass column, a peristaltic tube, a bottle stopper piercer, a headspace bottle, and a water ring vacuum pump, wherein an ion exchange resin is precipitated inside the resin glass column, and after the water sample to be tested flows through the resin glass column, the nitrite and nitrate therein are completely exchanged with the chloride ions in the resin glass column, and then, the KCl solution flows through the resin glass column to achieve elution and separation of nitrite and nitrate. The system for separating nitrite and nitrate in water samples of the present application can completely separate nitrate and nitrite in water samples, and its separation degree, full process blank and recovery rate meet the accuracy requirements of isotope analysis, thereby improving the accuracy of the nitrogen and oxygen isotope values ​​of nitrate and nitrite determined by bacterial denitrification.

This invention discloses a quantitative method and system for the contribution of river nitrous oxide sources and fate processes, relating to the field of biotechnology. The method includes: collecting surface water and groundwater samples; determining the physicochemical properties of the water samples, including calculating and quantifying the water-to-groundwater exchange ratio; extracting dissolved nitrous oxide from the water samples after determining the physicochemical properties and performing isotope analysis on the nitrous oxide to generate isotope test results; conducting indoor culture experiments on the water samples after completing the isotope analysis to determine whether there are abiotic sources of nitrous oxide in the water samples, generating indoor culture results; and quantifying the contribution of river nitrous oxide sources based on the results of the water-to-groundwater exchange ratio, the isotope test results, and the indoor culture results. This invention effectively analyzes the sources and fate processes of nitrous oxide in rivers and accurately quantifies the contributions of different sources.

This invention relates to the field of mineral deposit exploration technology, specifically disclosing a method for determining the extension of magmatic hydrothermal deposits using fluid inclusions. The method involves collecting mineral samples containing fluid inclusions from the target deposit and its surrounding area using a systematic grid. Physicochemical parameters are obtained through petrography, microthermometry, and isotope analysis, and a spatial database is established. Multiple initial hydrothermal centers are identified. A multi-dimensional spatial constraint field is constructed, incorporating temperature-salinity-isotope gradients, mineralization depth, and magma-water mixing ratio. Using the initial centers as seed points, a neighborhood search is performed along the gradient synthesis direction. Sub-hydrothermal centers are generated and continuously grow when preset conditions are met, until an overlap threshold is reached, at which point iteration stops. All hydrothermal centers and growth paths are integrated to construct a spatial extension model. High-potential areas are screened using a target area evaluation index, and the extension direction and potential mineralization target areas are determined by combining the mineralization depth. This significantly improves the accuracy of concealed ore body prediction and the efficiency of mineral exploration.

This invention provides an apparatus, system, and method for analyzing altered carbonate carbon isotopes. The apparatus includes: an enrichment component comprising at least one enrichment tube having an enrichment section; and a freezing component comprising a container filled with a refrigerant. The enrichment section is completely immersed in the refrigerant to freeze the target gas generated by sample decomposition within the enrichment section to a target concentration. Based on the technical solution of this invention, analysis of low-content altered carbonate carbon isotopes can be achieved; it can also simultaneously acquire multiple sets of samples required for altered carbonate carbon isotope analysis, saving time for detecting large quantities of altered carbonate carbon isotopes. Furthermore, the operation is simple, reducing analytical costs and providing a reliable technical means for the application of geochemical exploration technology.

The invention discloses a river nitrogen pollution source analysis method based on process simulation and isotopic tracing, particularly relates to the technical field of river sewage treatment, and comprises hydrological simulation, nitrogen isotope analysis, nitrogen source analysis, model analysis and data processing and analysis. According to the method, the source and flux of nitrate nitrogen in a river system are simulated by utilizing a hydrological model, when long-term hydrogeological chemical data of a river are fully measured, a standard verification and simulation method is adopted, and for the river without measurement data, the emission amount of a field sample and nitrate nitrogen concentration data are used for helping to verify the hydrological model, so that the accuracy of the verification is improved. According to the method, a hydrological model is used for simulating river runoff and nitrate nitrogen flux so as to improve simulation accuracy, on the contrary, the hydrological model simulates river runoff and nitrate nitrogen flux so as to support calculation of isotope source flux, meanwhile, the hydrological model can also be used for verifying isotope-based results, and simulation results of the hydrological model and the isotope model are systematically integrated so as to realize reliable nitrate nitrogen space-time source tracking.

The invention relates to a river water quality influence evaluation method based on strontium isotope analysis and a radon model. Precise traceability is realized through a strontium isotope model technical method, and meanwhile, the influence of underground water of an irrigation area along a river on river water quality is quantified by applying a radon mass balance model. Specifically, by taking water quality analysis of the Yellow River irrigation area as an example, the method can accurately locate sources of complex pollutants such as carbonate rock weathering, soil mineral decomposition, chemical fertilizer loss and sewage leakage in underground water along the Yellow River irrigation area, solves the problem of confusion of natural and artificial pollution contributions, and fills the blank of underground water-surface water interaction influence quantification.

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 invention discloses a laser freezing denudation device and method for a non-solid sample, and relates to the technical field of laser denudation-inductively coupled plasma mass spectrometry detection, the laser freezing denudation device comprises a sample cell main body, a heat dissipation end, a temperature sensing line, a liquid inlet liquid nitrogen pipeline, a silver objective table, a sample moving device and a multifunctional sample groove; wherein the heat dissipation end, the temperature sensing line and the liquid nitrogen inlet pipeline are sequentially arranged outside the sample cell main body side by side; the silver objective table and the multifunctional sample tank are arranged in the sample cell main body; a rotatable part of the sample moving device is arranged outside the sample cell main body; and the silver objective table is connected with the heat dissipation end, the temperature sensing line and the liquid nitrogen inlet pipeline. The device can effectively control the sample temperature, improve the data quality of fluid inclusion and biological sample test, provide an efficient and direct detection means without pretreatment for formation water and trace solution element-isotope analysis, and has the advantages of low instrument equipment and experiment cost, and strong economical efficiency and operability.

The embodiment of the invention provides a cassiterite high-precision tin isotope determination method which comprises the following steps: selecting a cassiterite sample, grinding, and weighing the ground cassiterite sample; adding the weighed cassiterite sample into a sample dissolving tube, slowly adding high-purity hydrobromic acid into the sample dissolving tube, and heating and sealing the sample dissolving tube to completely dissolve cassiterite; taking out the dissolved sample, and diluting the dissolved sample to a constant volume; sequentially carrying out evaporation acid removal and redissolution on the diluted and constant-volume sample to obtain a sample to be measured; establishing a cup structure for Sn isotope static determination; and performing high-precision Sn isotope measurement on the to-be-measured sample according to the cup structure. According to the method, complete dissolution of cassiterite can be achieved, the extremely high tin recovery rate is ensured, the problem of extra isotope fractionation caused by solution volatilization in the processes of tin recovery incompleteness, dissolution and evaporation drying to medium conversion can be effectively solved, and therefore the accuracy and reliability of Sn isotope analysis are ensured.