A mass spectrometry ion source device and a mass spectrometer comprising the same

Abstract

The application belongs to the technical field of mass spectrometry instruments, and particularly relates to a mass spectrometry ion source device and a mass spectrometer comprising the same. The mass spectrometry ion source device comprises: a sample inlet device, a plasma ion source and a gas curtain, the sample inlet device is communicated with a structure for generating plasma in the interior of the plasma ion source through a first sample inlet channel, the sample inlet device is connected with the gas curtain through a second sample inlet channel, a high-temperature plasma flame outlet is arranged at the tail of the plasma ion source, and the direction in which the high-temperature plasma flame outlet sprays high-temperature plasma flame and the direction in which the gas curtain sprays gas are arranged to intersect each other. The application further provides a mass spectrometer with the above mass spectrometry ion source device. The mass spectrometry ion source device can simultaneously perform elementization high-energy ionization and organic matter ionization on a sample, so as to achieve the purpose of simultaneously detecting inorganic elements and organic elements in the sample by using mass spectrometry, and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of mass spectrometry instrument technology, specifically relating to a mass spectrometry ion source device and a mass spectrometer including the device. Background Technology

[0002] The development of analytical instruments is one of the important foundations and driving forces of modern scientific, economic, and social development. Among them, elemental analysis instruments and organic matter analysis instruments each play their respective roles in environmental monitoring, food safety, geological exploration, scientific research, industrial production, clinical diagnosis, and biomedicine, playing a vital role in national science and technology, economy, defense, people's livelihood, and social development. Elemental analysis instruments mainly focus on the analysis and detection of metals and metalloids, while organic matter analysis instruments focus on the qualitative and quantitative analysis of organic compounds; few instruments can be used for the simultaneous analysis of elements and organic compounds.

[0003] In practical applications, there are scenarios that require the simultaneous detection of inorganic elements and organic matter in samples. For example, in environmental monitoring, the monitoring of heavy metals and organic pollution in the atmosphere, water, and soil; and in food safety, the measurement of heavy metals and pesticides in grains, meat, and vegetables. These often require cumbersome sample collection and pretreatment processes, followed by independent analysis of heavy metals and organic matter on different instruments. This undoubtedly increases the cost of analytical instruments, the workload of operators, and reduces the timeliness and accuracy of the detection data. Therefore, developing an instrument that can simultaneously detect organic matter and metal elements is of great significance.

[0004] Mass spectrometry instruments began to be commercialized in the 1950s and were widely used for the structural analysis of various organic compounds, gradually becoming an important instrument for organic compound analysis. As is well known, the ion source is considered the "heart" of a mass spectrometer, a key component determining the instrument's analytical range, sensitivity, and spectral specificity. Early mass spectrometers mostly used simple electron impact sources (EI). In the 1990s, due to the needs of bioanalysis, some new ionization methods were rapidly developed, such as electro-jet ionization (ESI), chemical ionization (CI), atmospheric pressure chemical ionization (APCI), and matrix-assisted laser desorption / sorption ionization (MALDI). In 2004, Cooks et al. used desorbed electro-jet ionization (DESI) technology for mass spectrometry analysis, first proposing the concept of open-source mass spectrometry. Subsequently, over 20 atmospheric pressure ionization techniques with varying performances, such as Direct Real-Time Analytical Ionization (DART), Flowing Atmospheric Pressure Afterglow (FAPA), and Miniature Glow Discharge Plasma Ionization (MFGDP), were developed, propelling mass spectrometry into a new era of online, high-throughput detection of actual samples at atmospheric pressure without sample pretreatment. However, none of these organic mass spectrometry ionization sources are well-suited for elemental detection, primarily because their low energy levels make it difficult to meet the conditions required for elemental ionization. Therefore, currently, there are no instruments for organic mass spectrometry that can simultaneously monitor elements and organic compounds.

[0005] Compared to organic matter detection techniques, elemental detection techniques require high-temperature environments or high-energy-density excitation sources. Representative inorganic mass spectrometry techniques include inductively coupled plasma mass spectrometry (ICP-MS) and microwave plasma mass spectrometry (MWP-MS). Compared to other organic mass spectrometry ionization techniques (such as electro-jet ionization sources, matrix-assisted laser desorption / ionization sources, atmospheric pressure chemical ionization sources, and atmospheric pressure photoionization sources), ICP cannot be used for the detection of organic compounds because the high temperatures generated by the plasma (sensor temperature as high as 8000-10000K, and central channel temperature of 5000-7000K) cause organic molecules to completely fragment, leaving only detectable atomic components, namely metals, metalloids, or heteroatoms. In recent years, although the covalent labeling of biomacromolecules with elements such as Hg or I has enabled the detection of organic compounds using ICP-MS, the successful application of these methods heavily relies on the supplementation of molecular-specific detection techniques. For many small organic molecules that cannot be labeled, ICP-MS remains ineffective. MWP-MS is an inorganic mass spectrometry technique developed in the 1980s. The ion source for MWP-MS primarily uses the TM010 resonant cavity or a modified version thereof. Like ICP, the high temperature generated by the plasma (ranging from 2500-5000 K depending on the discharge gas and power) causes organic molecules to completely fragment, leaving only detectable atomic components, namely metals, metalloids, or heteroatoms. Therefore, existing MWP-MS designs cannot be directly used for the detection of organic compounds.

[0006] In summary, due to the significant differences in ionization conditions between metallic elements and organic compounds, conventional mass spectrometry ionization sources cannot efficiently ionize both simultaneously. Therefore, mass spectrometers used for elemental analysis cannot be used for the direct detection of organic compounds; and organic mass spectrometry ion sources cannot achieve elemental ionization, even when coupled with inorganic mass spectrometry. Currently, there is still a lack of mass spectrometry techniques capable of simultaneously analyzing organic compounds and elements. Summary of the Invention

[0007] To address the problems of the prior art, the present invention aims to provide a mass spectrometry ion source device for simultaneous analysis of organic and inorganic elements, and a mass spectrometer comprising the device.

[0008] A mass spectrometry ion source device for simultaneous analysis of organic and inorganic elements includes: a sample introduction device, a plasma ion source, and a gas curtain. The sample introduction device is connected to the plasma generation structure inside the plasma ion source through a first sample introduction path, and the sample introduction device is connected to the gas curtain through a second sample introduction path. A high-temperature plasma flame outlet is provided at the tail of the plasma ion source, and the direction of the high-temperature plasma flame ejected from the high-temperature plasma flame outlet is intersected with the direction of the gas ejected from the gas curtain.

[0009] Preferably, the plasma ion source includes a shell, inside which is a ceramic tube for ionizing carrier gas and sample. The first sample inlet passage and the high-temperature plasma flame outlet are respectively connected to the two ends of the ceramic tube. The side of the ceramic tube is also connected to a carrier gas inlet and a microwave power feed interface.

[0010] Preferably, the air curtain is a disc-shaped cavity with a through hole at the center, the side of the through hole is the air outlet of the air curtain, and the cross-sectional shape of the disc-shaped cavity in the radial direction is conical, wherein the narrow end of the cone faces the air outlet.

[0011] Preferably, the high-temperature plasma flame outlet is coaxially arranged with the through hole of the air curtain.

[0012] Preferably, the distance between the high-temperature plasma flame outlet and the air curtain is 0-50mm.

[0013] Preferably, the air curtain is equipped with a circulating water cooling device.

[0014] Preferably, the end of the air curtain is connected to a three-cone sampling interface, the three-cone sampling interface and the high-temperature plasma flame outlet are respectively located on both sides of the air curtain, and the three-cone sampling interface and the high-temperature plasma flame outlet are coaxially arranged.

[0015] Preferably, the three-cone sampling interface includes a sampling cone, a truncating cone, and a secondary truncating cone arranged coaxially in sequence.

[0016] Preferably, the sampling device includes a liquid sampling device, a sampling gas pump, and a drying tube, wherein the liquid sampling device is connected to an nebulizer;

[0017] One end of the drying tube is connected to the nebulizer and the sampling gas pump respectively, and the other end of the drying tube is connected to a three-way solenoid valve, which is connected to the first injection passage and the second injection passage respectively.

[0018] The present invention also provides a mass spectrometer for simultaneous analysis of organic and inorganic elements, wherein the ion source of the mass spectrometer adopts the above-mentioned ion source device.

[0019] Preferably, the mass spectrometer includes the aforementioned ion source device, cooling collision cell, and mass analyzer connected in sequence.

[0020] This invention integrates two sample introduction and ionization methods, utilizing the same plasma source to ionize samples under two different environments. This achieves high-energy ionization of elements and ionization of organic matter, enabling the simultaneous detection of organic and inorganic elements in samples using a mass spectrometer. The compact instrument structure simplifies the operation of methods for the simultaneous detection of organic and inorganic elements, reducing related detection costs and time consumption, and shows great promise for future applications.

[0021] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0022] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the ion source device and mass spectrometer of the present invention;

[0024] Figure 2 This is a schematic diagram of the sample introduction system of the present invention.

[0025] The components are: 1-sample introduction system, 101-three-way solenoid valve, 102-drying tube, 103-nebulizer, 104-liquid sample introduction device, 105-sampling gas pump, 2-first sample introduction path, 3-second sample introduction path, 4-carrier gas inlet, 5-microwave plasma ion source, 6-microwave power feed interface, 7-high temperature plasma flame outlet, 8-gas curtain, 9-sampling cone, 10-selection cone, 11-secondary selection cone, 12-cooling collision cell, 13-ion extraction electrode, 14-lens group, 15-mass analyzer. Detailed Implementation

[0026] Example 1: Mass spectrometry ion source device for simultaneous analysis of organic and inorganic elements

[0027] The mass spectrometry ion source device in this embodiment is as follows: Figure 1 , 2As shown, the system includes: a sample introduction device 1, a plasma ion source 5, and an air curtain 8. The sample introduction device 1 includes a liquid sample introduction device 104, a sampling gas pump 105, and a drying tube 102. The liquid sample introduction device 104 is connected to an nebulizer 103. One end of the drying tube 102 is connected to the nebulizer 103 and the sampling gas pump 105, respectively, and the other end of the drying tube 102 is connected to a three-way solenoid valve 101. The three-way solenoid valve 101 is connected to the first sample introduction passage 2 and the second sample introduction passage 3, respectively.

[0028] The sample introduction device 1 is connected to the plasma generation structure inside the plasma ion source 5 through the first sample introduction passage 2, and the sample introduction device 1 is connected to the air curtain 8 through the second sample introduction passage 3.

[0029] The plasma ion source 5 is equipped with a high-temperature plasma flame outlet 7 at its tail. The direction of the high-temperature plasma flame ejected from the high-temperature plasma flame outlet 7 is intersected with the direction of the gas ejected from the gas curtain 8. The high-temperature plasma flame outlet 7 and the gas curtain 8 do not contact each other, and both can be set to operate under normal pressure. During operation, the sample enters the plasma ion source 5 through the first sample inlet passage 2. The plasma ion source 5 generates high-temperature plasma, simultaneously elementalizing and ionizing the sample. The plasma flame carrying the elemental ions is then ejected from the high-temperature plasma flame outlet 7. Simultaneously, the sample is fed into the gas curtain 8 through the second sample inlet passage 3 and ejected from the gas outlet of the gas curtain 8. After the high-temperature plasma flame (containing ionized sample elements) ejected from the high-temperature plasma flame outlet 7 mixes and comes into contact with the sample gas ejected from the gas outlet of the gas curtain 8, the organic matter in the sample is ionized and carried forward by the plasma. The distance between the high-temperature plasma flame outlet 7 and the gas curtain 8 is preferably 0-50 mm, within which the high-temperature plasma flame can fully contact the gas sample. At this point, the plasma contains both ions of the sample elements and ions of organic matter, and analysis of it can simultaneously provide information on both inorganic elements and organic matter.

[0030] The plasma ion source 5 includes a shell, inside which is a ceramic tube for ionizing carrier gas and samples. The first sample inlet 2 and the high-temperature plasma flame outlet 7 are respectively connected to both ends of the ceramic tube. The side of the ceramic tube is also connected to a carrier gas inlet 4 and a microwave power feed interface 6. The carrier gas (helium or argon) enters through the carrier gas inlet 4, and the microwave power (frequency 2.45 GHz) is generated by a solid-state microwave power generator and fed into the ion source resonant cavity through the N-type connector of the microwave power feed interface 6 and the antenna.

[0031] The air curtain 8 is a disc-shaped cavity with a central through-hole. The side of the through-hole serves as the air outlet of the air curtain 8. The cross-sectional shape of the disc-shaped cavity in the radial direction is conical, with the narrow end of the cone facing the air outlet. The high-temperature plasma flame outlet 7 is coaxially arranged with the through-hole of the air curtain 8. In this air curtain 8 structure, after a gaseous sample is introduced into the air curtain 8, it can gather at the center of the through-hole in a 360-degree direction and collide with chemically active substances in the plasma afterglow, thereby improving the ionization efficiency of organic matter. In addition, the air curtain 8 is equipped with a circulating water cooling device, which can reduce the risk of organic molecules being broken down by high temperature and the rapid aging of components due to high temperature.

[0032] The end of the gas curtain 8 is connected to other structures of the mass spectrometer. In this embodiment, a three-cone sampling interface for sampling plasma containing sample element ions and organic ions is provided at the rear end of the gas curtain 8. The use of the three-cone sampling interface can effectively improve the sensitivity of the instrument. The three-cone sampling interface and the high-temperature plasma flame outlet 7 are respectively located on both sides of the gas curtain 8, and the three-cone sampling interface and the high-temperature plasma flame outlet 7 are coaxially arranged. The three-cone sampling interface includes a sampling cone 9, a truncating cone 10, and a secondary truncating cone 11 arranged coaxially in sequence.

[0033] Example 2: Mass spectrometer for simultaneous analysis of organic and inorganic elements

[0034] The mass spectrometer in this embodiment is as follows: Figure 1 , 2 As shown, the device includes, in sequence, the ion source apparatus of Embodiment 1, a cooled collision cell 12, an ion extraction electrode 13, a lens group 14, and a mass analyzer 15. The cooled collision cell 12 can be a quadrupole, hexapole, or octupole. The mass analyzer 15 can be an existing analyzer such as a quadrupole mass analyzer or a time-of-flight mass analyzer, designed using the orthogonal acceleration principle. A high-voltage double-pulse is used in the pulse acceleration region to improve the pulse voltage and signal-to-noise ratio, while effectively reducing interference from the high-voltage field in the acceleration region. Reflective second-order focusing can effectively improve the flight path and simultaneously achieve second-order focusing.

[0035] After the sample is ionized into elemental ions and organic ions in the ion source device, it enters the cooled collision cell 12 through the three-cone sampling interface, and then passes through the ion extraction electrode 13 and the lens group 14 before entering the mass analyzer 15 for mass spectrometry analysis. This enables simultaneous quantitative analysis of inorganic elements and organic matter in the sample.

Claims

1. A mass spectrometry ion source device for simultaneous analysis of organic and inorganic elements, characterized in that: include: The sample introduction device (1), plasma ion source (5), and gas curtain (8) are provided. The sample introduction device (1) is connected to the plasma generating structure inside the plasma ion source (5) through the first sample introduction passage (2). The sample introduction device (1) is connected to the gas curtain (8) through the second sample introduction passage (3). The tail of the plasma ion source (5) is provided with a high-temperature plasma flame outlet (7). The direction of the high-temperature plasma flame ejected from the high-temperature plasma flame outlet (7) is intersected with the direction of the gas ejected from the gas curtain (8).

2. The mass spectrometry ion source device according to claim 1, characterized in that: The plasma ion source (5) includes a shell, inside which is a ceramic tube for ionizing carrier gas and sample. The first sample inlet (2) and the high-temperature plasma flame outlet (7) are respectively connected to the two ends of the ceramic tube. The side of the ceramic tube is also connected to a carrier gas inlet (4) and a microwave power feed interface (6).

3. The mass spectrometry ion source device according to claim 1, characterized in that: The air curtain (8) is a disc-shaped cavity with a through hole in the center. The side of the through hole is the air outlet of the air curtain (8). The cross-sectional shape of the disc-shaped cavity in the radial direction is conical, and the narrow end of the cone faces the air outlet.

4. The mass spectrometry ion source device according to claim 3, characterized in that: The high-temperature plasma flame outlet (7) is coaxially arranged with the through hole of the air curtain (8).

5. The mass spectrometry ion source device according to claim 1, 3 or 4, characterized in that: The distance between the high-temperature plasma flame outlet (7) and the air curtain (8) is 0-50 mm.

6. The mass spectrometry ion source device according to claim 1, 3 or 4, characterized in that: The air curtain (8) is equipped with a circulating water cooling device.

7. The mass spectrometry ion source device according to claim 1, characterized in that: The end of the air curtain (8) is connected to a three-cone sampling interface. The three-cone sampling interface and the high-temperature plasma flame outlet (7) are located on opposite sides of the air curtain (8). The three-cone sampling interface and the high-temperature plasma flame outlet (7) are coaxially arranged.

8. The mass spectrometry ion source device according to claim 7, characterized in that: The three-cone sampling interface includes a sampling cone (9), a truncating cone (10), and a secondary truncating cone (11) arranged coaxially in sequence.

9. A mass spectrometer for simultaneous analysis of organic and inorganic elements, characterized in that: The ion source of the mass spectrometer is the ion source device according to any one of claims 1-8.

10. The mass spectrometer according to claim 9, characterized in that: The mass spectrometer includes an ion source device, a cooled collision cell (12), and a mass analyzer (15) as described in any one of claims 1-8, connected in sequence.

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