Flow tube photoionization mass spectrometer device with constant temperature sample introduction environment

Abstract

The utility model discloses a kind of flow tube photoionization mass spectrometry devices that can maintain constant-temperature sampling environment, including reaction cabin inside being equipped with reaction chamber, the outlet of quartz flow tube is connected with the reaction chamber import of reaction cabin, the import of mass spectrometry mechanism is connected with the reaction chamber export of reaction cabin, the import of quartz flow tube is equipped with sealed tee, the outlet of sealed tee is connected with the import of quartz flow tube, the import of sealed tee one place is equipped with quartz sampling boat, the import of sealed tee second place is connected with gas pipe for target gas is inhaled, quartz flow tube is close to the outside of one side of reaction cabin and is equipped with special-shaped quartz tube, the outside of one side of special-shaped quartz tube close to reaction cabin is equipped with heating wire.The utility model can solve the problem of unstable solid sample sampling concentration during experiment, and help mass spectrometry to detect free radicals and intermediates formed in reaction process.

Description

Technical Field

[0001] This utility model relates to the field of mass spectrometry analysis technology, and in particular to a flow tube photoionization mass spectrometer that can maintain a constant temperature sample introduction environment. Background Technology

[0002] Photoionization mass spectrometry (PMS) is a powerful experimental method for detecting the original odor of gaseous products, characterized by high sensitivity, fast analysis speed, broad applicability, and high accuracy. Therefore, this technique can obtain molecular structure information of organic substances, enabling qualitative and quantitative analysis, and is widely used in materials chemistry, biomedicine, combustion chemistry, and other fields. Sample sampling and detection are crucial, and PMS can achieve this through vacuum ultraviolet photoionization, for example, in combination with synchrotron radiation. Utilizing the high brightness, wide energy range, and continuously adjustable characteristics of synchrotron radiation, the sample being detected is subjected to "soft" ionization.

[0003] The pyrolysis reaction of solid samples involves a large number of stable and unstable products and transient intermediates. Photoionization mass spectrometry (PMS) can accurately detect these species, which is of great significance for studying the pyrolysis process and detailed reaction kinetics. However, current solid sample mass spectrometry analysis mainly relies on two sample introduction methods, both of which have fundamental technical bottlenecks:

[0004] Combustion furnace pretreatment: Solid samples are burned into a gaseous state in a combustion furnace at high temperatures, and then the samples are injected through a capillary tube and the reaction products are detected by mass spectrometry. This method has the problem of losing key reaction information. The combustion process completely destroys the chemical form of the sample, and short-lived intermediates such as free radicals cannot be captured by mass spectrometry.

[0005] Flow tube injection method: This method can be divided into two modes: one is to add a container outside the flow tube and inject the sample by heating the container; the other is to place the sample inside the flow tube for injection. Both modes have key problems: In the first mode, the external container causes sample condensation inside the injection tube, resulting in a low injection volume and difficulty in controlling the injection rate; in the second mode, thermodynamic runaway occurs in experiments involving injection within the flow tube. Temperature changes in the reaction zone (room temperature - 1150℃) cause fluctuations in sample temperature through heat conduction and radiation, leading to fluctuations in the actual injection volume, making it impossible to control the injection volume and presenting difficulties for low-pressure experiments. Both of these injection methods negatively impact the accuracy of experimental data. Utility Model Content

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a flow tube photoionization mass spectrometer that can maintain a constant-temperature sample introduction environment, thereby solving the problem of unstable solid sample concentration during experiments and helping mass spectrometry detect free radicals and intermediates formed during the reaction process. Simultaneously, the experimental environment can be adjusted according to experimental requirements to ensure experimental accuracy.

[0007] According to this utility model, a flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment includes a quartz flow tube, a reaction chamber, and a mass spectrometry analysis mechanism. The reaction chamber contains a reaction chamber. The outlet of the quartz flow tube is connected to the inlet of the reaction chamber of the reaction chamber. The inlet of the mass spectrometry analysis mechanism is connected to the outlet of the reaction chamber of the reaction chamber. A sealing tee is provided at the inlet of the quartz flow tube, and the outlet of the sealing tee is connected to the inlet of the quartz flow tube. A quartz sample boat is provided at one inlet of the sealing tee, and a gas tube for introducing a target gas is connected at the other two inlets of the sealing tee. A shaped quartz tube is fitted onto the outside of the quartz flow tube near the reaction chamber. A heating wire is provided on the outside of the shaped quartz tube near the reaction chamber, and the front wall of the reaction chamber is located outside the heating wire.

[0008] Preferably, a quartz bath is provided on the outside of the quartz flow tube near the sealing tee. The inlet of the quartz bath is connected to an external circulation thermostatic bath via a guide pipe and a liquid pump. The outlet of the quartz bath is connected to the interior of the external circulation thermostatic bath via a circulation pipe.

[0009] Preferably, a vacuum gauge for detecting the vacuum level inside the reaction chamber is installed on the side wall of the reaction chamber.

[0010] Preferably, an air extraction port is provided on the side wall of the reaction chamber, and a pump extraction pipe driven by a gas pump is connected to the air extraction port through a pump group butterfly valve. The signal output terminal of the vacuum gauge is connected to a pressure controller, and the signal output terminal of the pressure controller is connected to the signal input terminal of the pump group butterfly valve.

[0011] Preferably, a temperature-controlled thermocouple is provided near the heating wire in the irregularly shaped quartz tube, and the signal output terminal of the temperature-controlled thermocouple is connected to a temperature controller, the signal output terminal of the temperature controller being connected to the signal input terminal of the heating wire.

[0012] Preferably, the handle of the quartz sample boat has a mounting groove, and a thermocouple for detecting the internal temperature of the quartz sample boat is provided inside the mounting groove.

[0013] Preferably, the quartz flow tube is provided with a quartz screen inside, and the quartz screen is located behind the quartz sample boat.

[0014] Preferably, a sealed connection is provided between the end of the irregularly shaped quartz tube away from the reaction chamber and the quartz flow tube.

[0015] Preferably, the front wall of the reaction chamber is provided with a mullite insulation layer on the side near the heating wire.

[0016] Preferably, a foam insulation layer is provided on the outside of the guide pipe.

[0017] The beneficial effects of this utility model are:

[0018] A complete flow tube photoionization mass spectrometry (FMS) system capable of maintaining a constant-temperature sample introduction environment is provided. The system introduces the sample via a quartz sample boat, and the reaction chamber is connected to the differential chamber of the photoionization time-of-flight mass spectrometer (POFS). During the experiment, the pressure in the reaction chamber can be adjusted according to specific experimental requirements. The pressure difference between the reaction chamber and the differential chamber of the PFS allows stable products and short-lived intermediates generated during the reaction to pass through the differential chamber and the ionization chamber into the mass spectrometer for detection. This solves the problem of loss of critical reaction information encountered with samples with low melting (boiling) points and low saturated vapor pressures in experiments using traditional FFS systems.

[0019] Using a uniformly flowing isothermal liquid suppresses the high-temperature convection, conduction, and radiation from the reaction zone to the reaction sample, reducing the temperature fluctuation range of the sample area to within ±1.5℃. This solves the thermodynamic runaway problems encountered by samples with low melting (boiling) points and low saturated vapor pressures in experiments using traditional photoionization mass spectrometry devices.

[0020] A quartz flow tube is equipped with a quartz sieve, allowing a catalyst to be added before the sieve to study the reaction of samples within the quartz sample boat under the action of the catalyst. Furthermore, quartz flow tubes with quartz sieves at different positions can be fabricated to meet specific experimental requirements.

[0021] Using an external circulation thermostatic bath to achieve a constant liquid flow rate and circulate the liquid helps maintain a stable circulating liquid temperature while effectively saving the amount of circulating liquid used. Attached Figure Description

[0022] In the attached diagram: Figure 1 This is a schematic diagram of the flow tube photoionization mass spectrometer that can maintain a constant temperature sample introduction environment, as proposed in this utility model.

[0023] Figure 2 This is a three-dimensional diagram of the flow tube photoionization mass spectrometer that can maintain a constant temperature sample introduction environment proposed in this utility model.

[0024] Figure 3 This is a cross-sectional view of the flow tube photoionization mass spectrometer that can maintain a constant temperature sample introduction environment proposed in this utility model.

[0025] Figure 4 This is a cross-sectional view of the quartz screen inside the quartz flow tube proposed in this utility model.

[0026] Figure 5 The temperature inside the quartz sample boat under different conditions was measured using the thermocouple proposed in this utility model.

[0027] Figure 6 The mass spectrum (CF3) of the perfluorobutanesulfonamide pyrolysis system proposed in this invention. (Free radical generation).

[0028] Figure 7 The mass spectrum (C2F5) of the perfluorobutyramide pyrolysis system proposed in this invention. (Free radical generation).

[0029] In the diagram: 1-Thermocouple, 2-Quartz sample boat, 3-Quartz bath, 4-Flow guide tube, 5-Foam insulation layer, 6-External circulation thermostatic bath, 7-Flow controller, 8-Quartz flow tube, 9-Quartz sieve, 10-Irregular quartz tube, 11-Thermocouple, 12-Mullite insulation layer, 13-Front wall of reaction chamber, 14-Heating wire, 15-Temperature controller, 16-Vacuum gauge, 17-Pump group butterfly valve, 18-Pump group exhaust pipe, 19-Pressure controller, 20-Reaction chamber, 21-Sealed tee, 22-Sealed adapter. Detailed Implementation

[0030] Reference Figure 1 , Figure 2 and Figure 3 A flow tube photoionization mass spectrometry device capable of maintaining a constant temperature sample introduction environment includes a quartz flow tube 8, a reaction chamber 20, and a mass spectrometry analysis mechanism. The reaction chamber 20 is equipped with a reaction chamber. The outlet of the quartz flow tube 8 is connected to the inlet of the reaction chamber of the reaction chamber 20. The inlet of the mass spectrometry analysis mechanism is connected to the outlet of the reaction chamber of the reaction chamber 20. A sealing tee 21 is provided at the inlet of the quartz flow tube 8. The outlet of the sealing tee 21 is connected to the inlet of the quartz flow tube 8. A quartz sample boat 2 is provided at one inlet of the sealing tee 21. A gas tube for introducing the target gas is connected at the other two inlets of the sealing tee 21. A shaped quartz tube 10 is sleeved on the outside of the quartz flow tube 8 near the reaction chamber 20. A heating wire 14 is provided on the outside of the shaped quartz tube 10 near the reaction chamber 20. A front chamber wall 13 of the reaction chamber is provided on the outside of the heating wire 14.

[0031] Obviously, based on the above: the solid sample is introduced into the quartz flow tube 8 through the quartz sample boat 2, and the target gas is introduced through the two inlets of the sealed tee 21. The temperature inside the quartz flow tube 8 is heated to the target temperature by the heating wire 14. After the reaction is completed, the product is introduced into the mass spectrometry analysis mechanism through the reaction chamber to realize photoionization mass spectrometry detection.

[0032] It should be noted that the mass spectrometry analysis mechanism used in this device is a photoionization time-of-flight mass spectrometer, which is a mature product already in use on the market and does not involve structural improvements, so it will not be described in detail here.

[0033] Specifically, the gas pipe has a flow controller 7 for controlling the flow rate of the incoming gas. The model of the flow controller 7 is MKS Instruments 647C.

[0034] Obviously, based on the above: the target gas is introduced into the quartz flow tube (8) through the gas pipe from the target gas storage tank, and the flow rate of the target gas is adjustable through the flow controller 7.

[0035] In this embodiment: a quartz bath 3 is provided on the outside of the quartz flow tube 8 near the sealing tee 21. The inlet of the quartz bath 3 is connected to an external circulation thermostatic bath 6 through a guide pipe 4 and a liquid pump. The outlet of the quartz bath 3 is connected to the interior of the external circulation thermostatic bath 6 through a circulation pipe.

[0036] Obviously, based on the above, the temperature of the sample in the quartz sample boat 2 is controlled by the quartz bath 3 at the front end of the quartz flow tube 8. This effectively reduces the heat transfer effect on the sample in the quartz sample boat 2 caused by the temperature change of the heating wire 14 in the reaction zone during the experiment, ensuring a stable sample injection volume during the experiment.

[0037] Specifically, the quartz bath 3 is designed so that the constant temperature liquid carries the heat radiated from the heating wire 14, ensuring the temperature of the sample area. At the same time, if the sample injection volume is insufficient, the temperature of the liquid can be increased to help the sample evaporate and increase the injection volume.

[0038] Specifically, a foam insulation layer 5 is also provided on the outside of the guide pipe 4 to reduce heat loss during the transportation process.

[0039] In this embodiment, a vacuum gauge 16 for detecting the vacuum level inside the reaction chamber is installed on the side wall of the reaction chamber 20.

[0040] Obviously, based on the above, the setting of vacuum gauge 16 makes it easier for operators to monitor the vacuum level in the reaction chamber in real time.

[0041] In this embodiment: an exhaust port is provided on the side wall of the reaction chamber 20. The exhaust port is connected to a pump group exhaust pipe 18 driven by a gas pump through a pump group butterfly valve 17. The signal output terminal of the vacuum gauge 16 is connected to a pressure controller 19. The pressure controller is an MKS 600 series pressure controller. The signal output terminal of the pressure controller 19 is connected to the signal input terminal of the pump group butterfly valve 17.

[0042] Obviously, based on the above: by controlling the opening of the pump group butterfly valve 17 through the pressure controller 19, the pressure in the reaction chamber can be adjusted so that the pressure in the reaction chamber meets the experimental requirements.

[0043] In this embodiment: a temperature-controlled thermocouple 11 is provided near the heating wire 14 in the irregular quartz tube 10. The signal output terminal of the temperature-controlled thermocouple 11 is connected to a temperature controller 15, the model of which is 15CKW-3100. The signal output terminal of the temperature controller 15 is connected to the signal input terminal of the heating wire 14.

[0044] Obviously, based on the above: by detecting the temperature at the heating wire 14 through the thermocouple 11, and controlling the heating temperature of the heating wire 14 through the temperature controller 15, the temperature inside the quartz flow tube 8 meets the experimental requirements.

[0045] In this embodiment: the handle of the quartz sample boat 2 is provided with a mounting groove, and a thermocouple 1 for detecting the internal temperature of the quartz sample boat 2 is provided inside the mounting groove.

[0046] Obviously, based on the above, it is convenient for operators to monitor the sample temperature inside the quartz sample boat 2 in real time, and by adjusting the temperature of the external circulation constant temperature bath 6, it is beneficial to suppress the high temperature in the reaction zone from heat convection, heat conduction and heat radiation to the reaction sample.

[0047] In this embodiment: Refer to Figure 4 The quartz flow tube 8 is equipped with a quartz sieve 9 inside. The diameter of a single sieve hole in the quartz sieve 9 is 0.5 mm. The quartz sieve 9 is located behind the quartz sample boat.

[0048] Obviously, based on the above, a catalyst can be added in front of the quartz sieve 9 to study the reaction of the sample in the quartz sample boat under the action of the catalyst.

[0049] In this embodiment, a sealed transition 22 is provided between the end of the irregular quartz tube 10 away from the reaction chamber 20 and the quartz flow tube 8.

[0050] Obviously, based on the above, the sealing adapter 22 can further enhance the overall sealing performance of the device.

[0051] In this embodiment, a mullite insulation layer 12 is provided on the side of the front wall 13 of the reaction chamber near the heating wire 14.

[0052] Obviously, based on the above, the mullite insulation layer 12 can prevent heat loss from the quartz flow tube 8, which would lead to an unstable temperature environment and enhance the insulation effect.

[0053] To more clearly illustrate the implementation plan and its effects, we will use the attached diagram as an example:

[0054] Taking the pyrolysis experiment of perfluorobutyrate (C4F9SO2NH2) as an example, the solid reactant perfluorobutyrate is first placed in a quartz sample boat 2. A constant-temperature water bath at 35°C is introduced into the quartz bath 3 using an external circulation constant-temperature bath 6. Ar is then introduced into a quartz flow tube 8 with an inner diameter of 7.0 mm, and its flow rate is controlled by an MKS flow controller 7. The reactants pass through a 200 mm thermal radiation zone in the quartz flow tube 8. During the reaction, the reactor temperature in the quartz flow tube 8 is maintained below 1000°C for an extended period thanks to the heating wire 14 and the mullite insulation layer 12. The pressure inside the tube is controlled by a pump group butterfly valve 17 to maintain a pressure of 30 Torr, thereby reducing molecular collisions and preserving reactive free radicals. The gaseous reactants and reaction products enter the photoionization chamber of the mass spectrometry analysis unit. After photoionization, they are transmitted to the mass spectrometry chamber for detection by a time-of-flight mass spectrometer.

[0055] The ionization source is synchrotron radiation drawn from the burning beamline of the Hefei Synchrotron Radiation Facility, with an energy range of 5.0-24.5 eV.

[0056] like Figure 5 As shown, the temperature inside the quartz bath 3 can be kept relatively stable by the action of the constant temperature liquid inside the quartz sample boat 2 (the area where the sample is located) at different temperatures.

[0057] Experimental results are as follows Figure 6 , Figure 7 As shown, CF3 can be clearly observed in the pyrolysis system of perfluorobutyrate. and C2F5 The generation of free radicals. The experimental results above demonstrate that this device can ensure the smooth progress of solid sample pyrolysis experiments.

[0058] In summary:

[0059] (1) A complete flow tube photoionization mass spectrometry device capable of maintaining a constant temperature sample introduction environment is provided. The device introduces the sample through a quartz sample boat 2, and the reaction chamber is connected to the differential chamber of the photoionization time-of-flight mass spectrometer. The pressure in the reaction zone can be adjusted according to specific experimental requirements, such as 760 torr, 30 torr, or 5 torr. The differential chamber pressure of the photoionization time-of-flight mass spectrometer is generally around 1... 10 -4 Pa~5 10 -3 Within the Pa range, such a large pressure difference allows stable products and short-lived intermediates generated during the reaction to pass through the differential chamber and ionization chamber into the mass spectrometer for detection. This solves the problem of loss of key reaction information encountered in experiments with samples with low melting and boiling points and low saturated vapor pressures using traditional photoionization mass spectrometry devices.

[0060] (2) Using a uniformly flowing isothermal liquid to suppress the high-temperature convection, heat conduction, and heat radiation from the reaction zone to the reaction sample, reducing the temperature fluctuation range of the reaction sample area to within ±1.5℃. This solves the problem of thermodynamic runaway encountered by samples with low melting and boiling points and low saturated vapor pressure in experiments using traditional photoionization mass spectrometry devices;

[0061] (3) A quartz sieve is installed inside the quartz flow tube, and a catalyst can be added in front of the quartz sieve to study the reaction of the sample in the quartz sample boat under the action of the catalyst. In addition, quartz flow tubes with quartz sieves at different positions can be processed according to specific experimental needs to meet the experimental requirements;

[0062] (4) Using an external circulation thermostatic bath to achieve constant liquid flow rate and circulation is beneficial to maintaining stable circulating liquid temperature while effectively saving the amount of circulating liquid used.

Claims

1. A flow tube photoionization mass spectrometer capable of maintaining a constant-temperature sample introduction environment, characterized in that: The system includes a quartz flow tube (8), a reaction chamber (20), and a mass spectrometry analysis mechanism. The reaction chamber (20) has a reaction chamber inside. The outlet of the quartz flow tube (8) is connected to the inlet of the reaction chamber of the reaction chamber (20). The inlet of the mass spectrometry analysis mechanism is connected to the outlet of the reaction chamber of the reaction chamber (20). A sealing tee (21) is provided at the inlet of the quartz flow tube (8). The outlet of the sealing tee (21) is connected to the inlet of the quartz flow tube (8). A quartz sample boat (2) is provided at one inlet of the sealing tee (21). A gas pipe for introducing the target gas is connected at the other two inlets of the sealing tee (21). A shaped quartz tube (10) is sleeved on the side of the quartz flow tube (8) near the reaction chamber (20). A heating wire (14) is provided on the side of the shaped quartz tube (10) near the reaction chamber (20). The front chamber wall (13) of the reaction chamber is provided on the outside of the heating wire (14).

2. The flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 1, characterized in that: The quartz flow tube (8) is provided with a quartz bath (3) on the side near the sealing tee (21). The inlet of the quartz bath (3) is connected to an external circulation constant temperature bath (6) through a guide pipe (4) and a liquid pump. The outlet of the quartz bath (3) is connected to the interior of the external circulation constant temperature bath (6) through a circulation pipe.

3. The flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 1, characterized in that: A vacuum gauge (16) for detecting the vacuum level inside the reaction chamber is installed on the side wall of the reaction chamber (20).

4. The flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 3, characterized in that: The reaction chamber (20) has an air extraction port on its side wall. The air extraction port is connected to a pump group extraction pipe (18) driven by a gas pump through a pump group butterfly valve (17). The signal output terminal of the vacuum gauge (16) is connected to a pressure controller (19). The signal output terminal of the pressure controller (19) is connected to the signal input terminal of the pump group butterfly valve (17).

5. The flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 1, characterized in that: The irregular quartz tube (10) is provided with a temperature control thermocouple (11) near the heating wire (14). The signal output end of the temperature control thermocouple (11) is connected to a temperature controller (15). The signal output end of the temperature controller (15) is connected to the signal input end of the heating wire (14).

6. The flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 1, characterized in that: The handle of the quartz sample boat (2) has an installation groove, and a thermocouple (1) for detecting the internal temperature of the quartz sample boat (2) is provided inside the installation groove.

7. The flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 1, characterized in that: The quartz flow tube (8) is equipped with a quartz screen (9) inside, and the quartz screen (9) is located behind the quartz sample boat.

8. The flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 1, characterized in that: A sealed connector (22) is provided between the end of the irregular quartz tube (10) away from the reaction chamber (20) and the quartz flow tube (8).

9. A flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 1, characterized in that: The front wall (13) of the reaction chamber is provided with a mullite insulation layer (12) on the side near the heating wire (14).

10. A flow tube photoionization mass spectrometer capable of maintaining a constant temperature sample introduction environment according to claim 2, characterized in that: The outer side of the guide pipe (4) is covered with a foam insulation layer (5).

Images