A carbonate carbon isotope analysis device

Abstract

The application relates to a carbonate carbon and oxygen isotope analysis device which comprises a rotating table and a measuring mechanism, a plurality of ablation cell cavities are arranged on the rotating table along the circumference of the rotating table, the ablation cell cavities are provided with gas inlets and outlets; components of the measuring mechanism are sequentially arranged along the ablation cell cavities, and the measuring mechanism comprises a laser system, an exhaust unit, a purification sampling unit and a gas isotope mass spectrometer; the laser system is located above the ablation cell cavities and is provided with a laser action area, the laser action area is located on the movement path of the ablation cell cavities; the exhaust unit is used for being connected with the gas inlets and outlets to replace air in the ablation cell cavities with helium; the purification sampling unit is used for being connected with the gas inlets and outlets to sample; and the gas isotope mass spectrometer is connected with the purification sampling unit. The ablation cell cavities are arranged on the rotating table, and the measuring mechanism is matched, so that different samples can be independently and continuously subjected to exhaust, ablation reaction and purification test, and the test efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of isotope analysis of rock minerals, in particular to a carbonate carbon and oxygen isotope analysis device. BACKGROUND

[0002] In recent years, micro-area in-situ technology has been increasingly applied in the fields of geology, archaeology, biology, etc. However, the related instruments developed are mainly secondary ion sampling systems (such as SIMS) or laser ablation inductively coupled systems (such as LA-ICP-MS), and the development of micro-area in-situ analysis technology in the field of gas stable isotope analysis is extremely limited.

[0003] Gas stable isotope refers to the nuclides of H, C, N, O, S and other elements that can form stable gas forms. This kind of gas is analyzed by a special instrument system to obtain the highest accuracy: that is, by connecting various external devices for sample preparation and continuous flow analysis through a gas stable isotope gas mass spectrometer (IRMS), the common external devices are elemental analyzer EA, gas chromatograph GC, liquid chromatograph LC, gas pre-concentration system (such as PreCon), multifunctional gas preparation and introduction device (GasBench), etc. However, these external devices can only process the whole sample and then send it into the external device to be converted into the corresponding stable gas form, and then send it into the gas isotope mass spectrometer for analysis, which fails to realize micro-area in-situ gas stable isotope high-precision analysis.

[0004] The existing carbonate mineral carbon and oxygen isotope analysis technology using laser ablation is as follows: a laser and a modified microscopic optical device are coaxially installed, a high-energy laser beam is focused on the sample surface through an optical system, the chemical bonds of the sample are destroyed by generating extremely high temperature, the carbonate sample is decomposed to produce CO2, the vacuum purified CO2 is collected offline, and then the collected CO2 is sent into the sample introduction system of the gas stable isotope gas mass spectrometer for testing. This method is offline and can only manually test one sample at a time. At present, there is no laser ablation system applied to the online analysis device of the gas stable isotope gas mass spectrometer for carbonate carbon and oxygen isotope. SUMMARY

[0005] The embodiment of the present application provides a carbonate carbon and oxygen isotope analysis device to solve the problem of low test efficiency that only one sample can be tested at a time in the related art.

[0006] To achieve the above object, the present application provides the following technical scheme: a carbonate carbon and oxygen isotope analysis device, comprising: a rotating table, a measuring mechanism, a plurality of ablation cell cavities are arranged on the rotating table along the circumference thereof, and the ablation cell cavities have gas inlets and outlets; components of the measuring mechanism are sequentially distributed along the ablation cell cavities, and the measuring mechanism comprises: a laser system, an exhaust unit, a purification sampling unit and a gas isotope mass spectrometer; the laser system is located above the ablation cell cavities and has a laser action area, and the laser action area is located on a movement path of the ablation cell cavities; the exhaust unit is used for docking with the gas inlets and outlets to replace air in the ablation cell cavities with helium; the purification sampling unit is used for docking with the gas inlets and outlets to sample; the gas isotope mass spectrometer is connected with the purification sampling unit; and on the movement path, the distance between the laser action areas of two adjacent laser systems is a positive integer multiple of the distance between two adjacent ablation cell cavities.

[0007] The exhaust unit comprises: a first double-needle, which is used for docking with the gas inlets and outlets, and the first double-needle comprises two gas paths, one of which is used for gas transmission, and the other of which is used for discharging gas in the ablation cell cavities to exclude impurity air.

[0008] The exhaust unit further comprises: a first air cylinder, the moving shaft of which is connected with the first double-needle.

[0009] The rotating table is provided with a driving device at the bottom end, the rotating output end of the driving device is fixedly connected with the rotating table; and the ablation cell cavity upper cover is provided with a cell cover in which a window sheet is embedded.

[0010] The window sheet seals the cell cover through a flange and a rubber ring.

[0011] The gas inlets and outlets comprise: a through pipe, a side cover and a gasket, the through pipe is in communication with the ablation cell cavities and extends out of the surface of the rotating table at one end; the side cover is threadedly connected to one end of the through pipe, a through hole is formed in the middle of the side cover; the gasket is arranged on the side cover and seals the through hole, and the gasket is movably connected with the first double-needle.

[0012] When the laser action area works, the laser action area is located at the center position of the ablation cell cavities.

[0013] The purification sampling unit comprises a second double-path needle, a six-way valve, a first cold trap, a second cold trap and a pipeline. The second double-path needle is arranged on one side of the gas inlet and outlet and is connected with the gas inlet and outlet. The second double-path needle comprises two gas paths, one of which is used for gas transmission, and the other of which is used for discharging gas in the ablation cell for sampling. The first cold trap is arranged upstream of the six-way valve along the gas flow direction. The second cold trap is arranged downstream of the six-way valve along the gas flow direction. The pipeline is used for connecting the second double-path needle, the six-way valve, the first cold trap, the second cold trap and the glass tube. The six-way valve is numbered counterclockwise as 1, 2, 3, 4, 5 and 6. The first cold trap is connected with the No. 1 connector. The second cold trap inlet is connected with the No. 2 connector. The No. 3 connector is connected with low-speed helium. The No. 4 connector is connected with the glass tube. The No. 5 connector is connected with the second cold trap outlet. The No. 6 connector is connected with the air.

[0014] The purification sampling unit further comprises a second cylinder and a third cylinder. The second cylinder is connected with the second double-path needle through a movable shaft. The third cylinder is arranged on one side of the second cold trap and is connected with the second cold trap through a movable shaft.

[0015] The gas isotope mass spectrometer is connected with the glass tube.

[0016] The technical scheme provided by the application has the following beneficial effects:

[0017] The carbon and oxygen isotope analysis device provided by the application comprises a plurality of ablation cell cavities arranged on a rotating table and a measuring mechanism. When the carbon and oxygen isotope of the carbonate is analyzed, the positions of the distribution and exhaust unit, the laser ablation unit and the purification sampling unit relative to the cavities are adjusted, so that the laser ablation of some samples and the isotope analysis of other samples can be performed simultaneously. The device can make different samples independently and continuously perform exhaust, ablation reaction and purification test, solves the problem that the carbon and oxygen laser micro-area analysis of the carbonate cannot be tested on line and continuously, and improves the test efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical scheme in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Fig. 1 The overall device front view structure diagram provided by the embodiment of the application is shown in the figure.

[0020] Fig. 2 The laser system and the rotating table top view provided by the embodiment of the application are shown in the figure.

[0021] In the figure: 1, rotating table; 100, ablation cell cavity; 101, cell cover; 102, window sheet; 103, through pipe; 104, side cover; 105, gasket; 11, driving device;

[0022] 2, laser system;

[0023] 3, purification sampling unit; 30, second cylinder; 31, second double-way needle; 32, pipeline; 33, first cold trap; 34, second cold trap; 35, six-way valve; 36, glass tube; 37, third cylinder;

[0024] 4, gas isotope mass spectrometer;

[0025] 5, exhaust unit; 50, first cylinder; 51, first double-way needle. DETAILED DESCRIPTION

[0026] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0027] Referring to Figs. 1-2 , the embodiments of the present application provide a carbonate carbon and oxygen isotope analysis device, which comprises a rotating table 1 and a measuring mechanism. A plurality of ablation cell cavities 100 are arranged along the circumference of the rotating table 1, and the ablation cell cavities 100 have gas inlets and outlets. The components of the measuring mechanism are sequentially distributed along the ablation cell cavities 100. The measuring mechanism comprises a laser system 2, an exhaust unit 5, a purification sampling unit 3 and a gas isotope mass spectrometer 4. The laser system 2 is located above the ablation cell cavities 100 and has a laser action area. The laser action area is located on the movement path of the ablation cell cavities 100. The exhaust unit 5 is used to be connected with the gas inlets and outlets to replace the air in the ablation cell cavities 100 with helium. The purification sampling unit 3 is used to be connected with the gas inlets and outlets to take samples. The gas isotope mass spectrometer 4 is connected with the purification sampling unit 3. In addition, the distance between the laser action areas of two adjacent laser systems 2 on the movement path is an integer multiple of the distance between two adjacent ablation cell cavities 100.

[0028] A plurality of ablation cell cavities 100 are arranged on the rotating table 1, and the exhaust unit 5 and the purification sampling unit 3 are sequentially arranged. When performing carbonate carbon and oxygen isotope analysis, laser ablation of some samples and isotope analysis of other samples can be performed simultaneously. The device can make different samples independently and continuously perform exhaust, enrichment and testing, and can improve the efficiency of testing.

[0029] When the carbon and oxygen isotope analysis of carbonate is carried out, first, the sample is pretreated, the carbonate sample is cut to a size not greater than the size of the ablation cell 100, heated at 700℃ to remove water vapor and surface organic matter, and then each sample is placed in a different ablation cell 100 and sealed;

[0030] Then, the air in the ablation cell 100 is discharged, the He gas switch is opened, and the air in the ablation cell 100 is completely replaced with He gas;

[0031] Next, the sample surface is ablated, the rotating table 1 is rotated by a certain angle, the ablation cell 100 in which the air is discharged is placed under the laser system 2, the laser action area is located at the center position of the ablation cell 100 when the laser action area is working, the size of the laser spot is adjusted, and the position to be analyzed is aligned, and the laser is turned on to ablate the sample surface, and the high-temperature decomposition of calcium carbonate produces CO2;

[0032] Then, CO2 enrichment is carried out, in the enrichment mode, the CO2 gas in the ablation cell 100 is discharged, the discharged gas passes through the purification sampling unit 3, the CO2 gas produced by ablation is frozen, and other possible low-boiling-point impurity gases are discharged to the atmosphere;

[0033] Finally, the frozen CO2 is quickly sublimed and sent into the gas isotope mass spectrometer 4 by a low-flow-rate He gas (flow rate 0.5-3 mL / min) for carbon and oxygen isotope testing.

[0034] The air exhaust unit 5 comprises a first double-needle 51, the first double-needle 51 is connected with the gas inlet and outlet, the first double-needle 51 comprises two gas paths, one of which is used for gas transmission, and the other of which is used for discharging the gas in the ablation cell 100 to remove impurity air; the air exhaust unit 5 further comprises a first air cylinder 50, the movable shaft of the first air cylinder 50 is connected with the first double-needle 51.

[0035] The bottom end of the rotating table 1 is provided with a driving device 11, the rotating output end of the driving device 11 is fixedly connected with the rotating table 1; the upper cover of the ablation cell 100 is provided with a cell cover 101 in which a window piece 102 is embedded, the gas inlet and outlet comprises a through pipe 103, a side cover 104 and a gasket 105, the through pipe 103 is in communication with the ablation cell 100 and extends out of the surface of the rotating table 1 at one end; the side cover 104 is threadedly connected to one end of the through pipe 103, a through hole is formed in the middle of the side cover 104; the gasket 105 is arranged on the side cover 104 and seals the through hole, and the gasket 105 is movably connected with the first double-needle 51.

[0036] The driving device 11 is a stepping turntable, and the driving rotating table 1 rotates by a certain angle, so that the ablation cell cavity 100 is placed below the laser system 2. After a plurality of samples are respectively placed in different ablation cell cavities 100, the window sheet 102 is covered, the window sheet 102 seals the cell cover 101 through the flange and the rubber ring, the rubber ring is a fluorine rubber O-shaped ring, which is used to close the flange joint on the cell cover 101, the first double-needle 51 has two gas paths, one of which is connected to He gas, and the other of which is connected to air. When the air in the ablation cell cavity 100 is discharged, the He gas switch is opened, and the first double-needle 51 is pierced through the gasket 105 by the first cylinder 50. The gasket 105 is made of butyl rubber. After a few minutes (depending on the He gas flow rate and the size of the cavity), the air in the ablation cell cavity 100 can be completely replaced by He gas. Then the first double-needle 51 is pulled out by the first cylinder 50.

[0037] The purified sampling unit 3 includes a second double-needle 31, a six-way valve 35, a first cold trap 33, a second cold trap 34, and a pipeline 32. The second double-needle 31 is arranged on one side of the gas inlet and outlet and is connected to the gas inlet and outlet. The second double-needle 31 includes two gas paths, one of which is used for gas transmission, and the other of which is used for discharging the gas in the ablation cell cavity 100 for sampling. The first cold trap 33 is arranged upstream of the six-way valve 35 along the gas flow direction. The second cold trap 34 is arranged downstream of the six-way valve 35 along the gas flow direction. The pipeline 32 is used to connect the second double-needle 31, the six-way valve 35, the first cold trap 33, the second cold trap 34, and the glass tube 36. The six-way valve 35 is numbered counterclockwise as 1, 2, 3, 4, 5, and 6. The No. 1 connector is connected to the first cold trap 33. The No. 2 connector is connected to the inlet of the second cold trap 34. The No. 3 connector is connected to low-speed helium. The No. 4 connector is connected to the glass tube 36. The No. 5 connector is connected to the outlet of the second cold trap 34. The No. 6 connector is connected to air. The purified sampling unit 3 further includes a second cylinder 30 and a third cylinder 37. The second cylinder 30 is connected to the second double-needle 31 through the movable shaft. The third cylinder 37 is arranged on one side of the second cold trap 34, and the movable shaft of the third cylinder 37 is connected to the second cold trap 34.

[0038] The gas isotope mass spectrometer 4 is connected to the glass tube 36 in an open form.

[0039] Specifically, the gas from the second cold trap 34 enters the glass tube 36, the other end of the glass tube 36 is open, and is inserted into two pipelines, which are a helium pipeline and a gas isotope mass spectrometer 4 pipeline. Since the gas isotope mass spectrometer 4 is in a vacuum environment, the gas isotope mass spectrometer 4 pipeline sucks the gas from the glass tube 36, and the helium pipeline continuously introduces helium into the glass tube 36 without entering air.

[0040] In the enrichment mode, the second cylinder 30 is pierced by the second double-needle 31, and the He gas (flow rate 10-30 mL / min) removes the CO2 gas in the inside of the erosion cell 100. The removed gas is first frozen in the first cold trap 33 at -70℃, and then enters the second cold trap 34 through the six-way valve 35, and the CO2 gas produced in the erosion is frozen in the second cold trap 34, and other possible N2 and other low-boiling-point impurity gases are discharged to the atmosphere.

[0041] When the sample is injected into the gas isotope mass spectrometer 4, the six-way valve 35 is switched to the injection mode, the second cold trap 34 is removed from the liquid nitrogen, the frozen CO2 is quickly sublimated, and is sent into the glass tube 36 by the low-flow-rate He gas (flow rate 0.5-3 mL / min) and then enters the gas isotope mass spectrometer 4 for carbon and oxygen isotope testing.

[0042] In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", and "connection" should be broadly understood, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] It should be noted that in the present application, relational terms such as "first" and "second" and the like are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0044] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A carbonate carbon-oxygen isotope analysis device, characterized by, It comprises: A rotating table (1) is provided with a plurality of ablation pool cavities (100) along its circumference, and the ablation pool cavities (100) have gas inlets and outlets; A measuring mechanism, each component of which is sequentially distributed along the ablation pool cavities (100), comprises: A laser system (2) located above the ablation pool cavities (100) and having a laser action area located on the movement path of the ablation pool cavities (100); An exhaust unit (5) used for interfacing with the gas inlets and outlets to replace the air in the ablation pool cavities (100) with helium; A purified sampling unit (3) used for interfacing with the gas inlets and outlets to sample; A gas isotope mass spectrometer (4) connected with the purified sampling unit (3); And the distance between the laser action areas of two adjacent laser systems (2) on the movement path is a positive integer multiple of the distance between two adjacent ablation pool cavities (100). The exhaust unit (5) comprises: A first double-needle (51) interfacing with the gas inlets and outlets, the first double-needle (51) comprising two gas paths, one of which is used for gas transmission, and the other of which is used for discharging the gas in the ablation pool cavities (100) to remove impurity air.

2. The carbonate carbonate-oxygen isotope analysis device of claim 1, wherein: The exhaust unit (5) further comprises: A first air cylinder (50) with a movable shaft connected with the first double-needle (51).

3. The carbonate carbonate oxygen isotope analyzer of claim 1, wherein: The rotating table (1) is provided at the bottom end with a driving device (11) with a rotating output end fixedly connected with the rotating table (1); The ablation pool cavities (100) are provided with pool covers (101) inlaid with window sheets (102).

4. The carbonate carbonate oxygen isotope analyzer of claim 3, wherein: The window sheets (102) seal the pool covers (101) through flanges and rubber rings.

5. The carbonate carbonate oxygen isotope analysis device of claim 1, wherein: The gas inlets and outlets comprise: A through pipe (103) in communication with the ablation pool cavities (100) and extending out of the surface of the rotating table (1) at one end; A side cover (104) threadedly connected to one end of the through pipe (103) and provided with a through hole in the middle; A gasket (105) provided on the side cover (104) and sealing the through hole, the gasket (105) being movably connected with the first double-needle (51).

6. The carbonate carbonate oxygen isotope analysis device of claim 1, wherein: When the laser action area is working, the laser action area is located at the center of the ablation pool cavities (100).

7. The carbonate carbonate oxygen isotope analyzer of claim 1, wherein: The purified sampling unit (3) comprises: A second double-needle (31) provided on one side of the gas inlets and outlets and interfacing with the gas inlets and outlets, the second double-needle (31) comprising two gas paths, one of which is used for gas transmission, and the other of which is used for discharging the gas in the ablation pool cavities (100) to sample; A six-way valve (35); A first cold trap (33) provided upstream of the six-way valve (35) along the gas flow direction; A second cold trap (34) provided downstream of the six-way valve (35) along the gas flow direction; A pipeline (32) is used to connect the second double-path needle (31), the six-way valve (35), the first cold trap (33), the second cold trap (34) and the glass tube (36); The six-way valve (35) is numbered counterclockwise as 1, 2, 3, 4, 5 and 6, the first cold trap (33) is connected to the No. 1 joint, the second cold trap (34) inlet is connected to the No. 2 joint, the low-speed helium is connected to the No. 3 joint, the glass tube (36) is connected to the No. 4 joint, the second cold trap (34) outlet is connected to the No. 5 joint, and the No. 6 joint is connected to the air.

8. The carbonate carbonate oxygen isotope analyzer of claim 7, wherein: The purification sampling unit (3) further comprises: A second cylinder (30) is connected to the second double-path needle (31) through a movable shaft; A third cylinder (37) is arranged on one side of the second cold trap (34), and the movable shaft of the third cylinder (37) is connected to the second cold trap (34).

9. The carbonate carbonate oxygen isotope analyzer of claim 7, wherein: The gas isotope mass spectrometer (4) is connected to the glass tube (36).

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