36 results about "Isotope-ratio mass spectrometry" patented technology

The invention discloses a fluid inclusion water hydrogen isotope analysis system. The fluid inclusion water hydrogen isotope analysis system comprises a water sample collection instrument and a TC / EA-IRMS combination instrument; the water sample collection instrument comprises a vacuum communication pipeline, a sample cracking device and a water sample collection device; the water sample collection device comprises a quartz collection tube, and a capillary tube part is formed on the lower end of the quartz collection tube; the TC / EA-IRMS combination instrument comprises a high-temperature splitting / element analyzer (TC / EA) and an isotope ratio mass spectrometry (IRMS), and the high-temperature splitting / element analyzer comprises a high-temperature reaction tube and a gas chromatographic column; by adopting the capillary tube part and a solid feeding way, the relatively small sample amount is needed, and the sample amount of the fluid inclusion can be effectively reduced.

The invention provides a method for determining the cadmium isotope ratio in rice by multi-receiver inductively coupled plasma mass spectrometry. The total cadmium content of the rice sample is obtained to obtain the separation and purification rate; step 3 is to perform microwave digestion on the rice sample to be tested to separate and purify the test liquid; step 4 uses multi-receiver inductively coupled plasma mass spectrometry to determine the cadmium isotope ratio in the test liquid; wherein, The separation and purification are specifically as follows: a, the nitric acid medium of the digestion solution is converted into a hydrochloric acid medium; b, the digestion solution of the hydrochloric acid medium is first rinsed with hydrochloric acid 5 times, and then washed twice with Milli-Q water to obtain an eluent; c to The eluent is eluted and collected; d, the eluent is changed from a hydrochloric acid medium to a nitric acid medium. The invention solves the technical problem of separation and purification of cadmium in rice samples with low cadmium content, can quickly and accurately restore the source of cadmium pollution, and has good application value.

The invention discloses a method for simultaneously measuring the composition of natural nitrate and nitrite nitrogen and oxygen isotopes, quantitatively converting nitrate and nitrite into corresponding organic esters and nitro compounds, and then adopting gas chromatography / pyrolysis / Simultaneous Determination of Nitric Acid and Nitrite δ by Gas Chromatography / Isotope Ratio Mass Spectrometry 18 O and delta 15 N determination. The method for simultaneously measuring the nitrogen and oxygen isotope composition of natural nitrate and nitrite of the present invention requires less sample consumption and does not cause loss, gain, exchange and fractionation of nitrogen and oxygen.

A mass spectrometry method comprising steps of generating an ion beam from an ion source; directing the ion beam into a collision cell; introducing into the collision cell through a gas inlet on the collision cell a charge-neutral analyte gas or reaction gas; ionizing the analyte gas or reaction gas in the collision cell by means of collisions between the analyte gas or reaction gas and the ion beam; transmitting ions from the ionized analyte gas or reaction gas from the collision cell into a mass analyzer; and mass analyzing the transmitted ions of the ionized analyte or reaction gas. The methods can be applied in isotope ratio mass spectrometry to determine the isotope abundance or isotope ratio of a reaction gas used in mass shift reactions between the gas and sample ions, to determine a corrected isotope abundance or ratio of the sample ions.

The present application relates to methods and apparatus for isotope ratio mass spectrometry. Isotope ratio mass spectrometry comprising: flowing through a separation device a liquid mobile phase containing a sample comprising at least one molecular species having an isotope ratio to be determined; Set or reduce the flow rate of the liquid mobile phase flowing through the separation device over time to achieve the desired isotope ratio accuracy; at least for the at least one molecular species that has emerged from the separation device while setting or reducing the flow rate performing mass analysis; determining at least one isotope ratio of said at least one molecular species from mass peak intensities of at least two isotopologues of said at least one molecular species according to said mass analysis, said mass analysis passing being sufficiently high to resolve between The mass resolution of the two most abundant mass peaks of the nominal mass of at least one of the isotopologues is performed.

The invention relates to a method for detecting a potato addition amount in a staple food product. The method for detecting the potato addition amount in the staple food product mainly comprises the following steps: (1) preparing a sample; (2) performing pretreatment on the sample; (3) using the isotope ratio mass spectrometry for detecting to obtain a stable isotope relative ratio of carbon, nitrogen, hydrogen and oxygen; and (4) performing qualitative and quantitative analysis by means of a chemometric method, determining whether the potato is added or not by means of discriminant analysis,and determining the amount of addition by means of a multiple linear regression equation. Compared with the prior art, the method for detecting the potato addition amount in the staple food product has the advantages of simple operation, convenient and rapid, high detection efficiency, high accuracy, good stability and reproducibility; no method for detecting the potato content in potato productsexists in the current national standard; and the invention not only can qualitatively determine whether the product adds the mashed potato or not, but also can quantitatively analyze the addition amount of the mashed potato, which has a good market application prospect.

The invention provides a calibration method for measuring trace elements in a sample by isotope dilution mass spectrometry, belonging to the field of isotope dilution mass spectrometry. When the isotope dilution mass spectrometry is used to determine the trace elements in the sample to be tested, when the isotope abundance ratios of the measured elements in the standard substance solution and the sample solution to be tested are not equal due to the interference of the matrix, the trace elements in the standard substance solution are determined respectively. The isotopic abundance ratio of the measured element and the isotopic abundance ratio of the measured element in the sample solution to be measured, and then calculate the correction coefficient K according to the correction method of the present invention; then use the K value to correct the measured value related to the sample to be measured , and finally realize the accurate determination of the content of trace elements in the sample to be tested by isotope dilution mass spectrometry. The method solves the influence of matrix interference of the sample to be tested on the determination accuracy when the content of trace elements in the sample to be tested is determined by isotope dilution mass spectrometry.

The invention discloses a method for measuring the nitrogen concentration based on a trace-gas preconcentration device-isotope ratio mass spectrometer (PreCon-IRMS). The method includes the steps that an isotope ratio mass spectrum serves as a nitrogen detector, the m / z 28 ion current intensity of a to-be-detected nitrogen sample is directly measured through the PreCon-IRMS, and then the concentration of the to-be-detected nitrogen sample is calculated according to the linear relationship between the m / z 28 ion current intensity of a standard nitrogen sample and the concentration. The method is easy to operate and short in measuring time.