Device for sample introduction ionization of mass spectrometer and mass spectrum detection system

Abstract

According to the device for sample introduction ionization of the mass spectrometer and the mass spectrometry detection system, a sample introduction pipeline is connected with an ionization tube through a sealing coupling piece, an inner electrode is arranged in the ionization tube, an outer electrode is wound on the outer surface of the ionization tube, high-voltage alternating current is connected between the inner electrode and the outer electrode, and a vacuum sealing piece is connected between the ionization tube and the sample introduction end of the mass spectrometer. One part of the sample is ionized through a plasma area generated in the ionization tube, the other sample is secondarily ionized with electrons, ions, metastable state particles and the like drifting from the plasma area at the vacuum sealing element, and the sample ions are more efficiently transmitted into a mass spectrometer for detection in a low-pressure environment generated by the vacuum sealing element. The device can effectively improve the ionization efficiency of a to-be-detected sample, prevent interference of impurities in the environment and improve the transmission efficiency of the sample and ions, so that the detection signal strength is improved, the detection limit is reduced, and the stability is improved; and the self-absorption sample injection can be realized by utilizing the air pressure difference without other auxiliary modes.

Description

Technical Field

[0001] The invention relates to the field of analytical instruments, and in particular to a device for sample injection and ionization of a mass spectrometer and a mass spectrometry detection system. Background Art

[0002] Mass spectrometry is one of the most widely used analytical techniques, with the characteristics of high sensitivity, high accuracy, fast analysis speed and strong qualitative ability. Ionization system and injection system are both important technologies in material detection and important components of mass spectrometry analysis. The ionization effect of the ionization system directly affects the types of sample ions that can be detected and their yields, while the design of the injection and ionization system directly affects whether the sample ions can be efficiently transmitted, thereby affecting the detection limit, sensitivity, signal-to-noise ratio, etc. of the detection instrument.

[0003] At present, in the process of mass spectrometry detection, the ionization system often uses inert rare gases such as helium or argon as the ionized gas. However, inert rare gases are expensive on the one hand, and on the other hand, they are mostly stored in gas cylinders, which are not convenient for transportation and carrying. The breakdown voltage of air at normal pressure is as high as 30kV / cm, which is easy to produce arcs and filamentary discharges during dielectric barrier discharge, making it difficult to produce stable plasma, resulting in low ionization efficiency. In addition, since the sample will be disturbed by the air background and impurities in the environment under normal pressure air environment, the transmission efficiency of ions is not high, and the noise level of the instrument is high in a complex air environment. Therefore, it is necessary to study a sample injection ionization method that can not only produce stable plasma under air conditions but also avoid the large loss of sample ions during transmission, so as to improve the efficiency of sample injection and ionization. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a device for ionization injection of a mass spectrometer so that the sample to be tested can be efficiently ionized and smoothly enter the mass spectrometer for detection, thereby solving the problems of low ionization efficiency, low ion transmission efficiency, high noise level, etc. caused by the traditional ionization injection method, and improving the efficiency of ionization and injection.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A device for mass spectrometer sample injection ionization comprises a sample injection pipeline, a high-voltage AC power supply, a sealing coupling, an outer electrode, an inner electrode, an ionization tube, and a vacuum seal. The sample injection pipeline is connected to the ionization tube through a sealing coupling. The inner electrode is placed in the ionization tube, preferably in the center of the ionization tube. The outer electrode surrounds the outside of the ionization tube. The high-voltage AC power supply is connected between the inner electrode and the outer electrode. One end of the vacuum seal is connected to the ionization tube, and the other end is connected to the mass spectrometer sample injection end. The sample injection pipeline is used to transport carrier gas or sample. The ionization system composed of the inner electrode, the outer electrode, the high-voltage AC power supply and the ionization tube is used to generate plasma. The sample enters the ionization tube, and a part of the sample passes through the plasma zone generated in the ionization tube to be ionized. The remaining sample is secondary ionized at the vacuum seal with electrons, ions, metastable particles, etc. drifting from the plasma zone, and the sample ions are more efficiently transmitted to the mass spectrometer for detection under the low-pressure environment generated by the vacuum seal.

[0007] Further: the inner electrode is a hollow thin-walled metal tube with an inner diameter of (1mm, 5mm], preferably, its inner diameter is 2mm; the inner diameter of the ionization tube is (2mm, 10mm], and the outer diameter is (3mm, 15mm], preferably, its inner diameter is 3mm, and the outer diameter is 5mm.

[0008] The distance between the outer surface of the inner electrode and the inner wall of the ionization tube is (0.1mm, 5mm], preferably, the distance is 1mm.

[0009] The cross-sectional shape of the ionization tube is a hollow circular ring, and the lengths of the inner electrode and the outer electrode are (0.5 mm, 200 mm]. The range and volume of the plasma zone can be regulated by controlling the overlap length of the inner electrode and the outer electrode in the axial direction of the ionization tube, thereby controlling the number of sample ions generated. Preferably, the overlap length is (50 mm, 200 mm).

[0010] The output voltage of the AC high-voltage power supply is (3kV, 20kV], preferably, its output voltage is 4kV; the output frequency of the AC high-voltage power supply is (10kHz, 100kHz], preferably, its output frequency is (20kHz, 25kHz].

[0011] The included angle between the sample injection pipeline and the ionization tube is (90°, 180°], preferably, the included angle is 180 degrees, and the included angle between the vacuum seal and the ionization tube is (90°, 180°], preferably, the included angle is 180 degrees.

[0012] The air pressure in the sealed cavity formed by the injection pipeline, the ionization tube and the vacuum seal is lower than a standard atmospheric pressure. The carrier gas or sample enters the ionization tube through a pump or enters the ionization tube by self-absorption using the air pressure difference. The sample ions to be entered into the mass spectrometer enter the mass spectrometer through the vacuum seal by self-absorption using the air pressure difference or driven by the airflow.

[0013] The ionization tube is a quartz glass tube or a ceramic tube, and the vacuum seal is made of polyetheretherketone (PEEK) or nylon material.

[0014] The carrier gas is air, helium, argon, nitrogen, etc. Preferably, it is air.

[0015] A device for mass spectrometer sample injection and ionization, comprising a sample injection pipeline, a high-voltage AC power supply, a sealing coupling, an outer electrode, an inner electrode, an ionization tube, and a vacuum seal. The sample injection pipeline is connected to the ionization tube through a seal. The inner electrode is placed in the ionization tube, preferably in the center of the ionization tube. The outer electrode surrounds the outside of the ionization tube. The high-voltage AC power supply is connected between the inner electrode and the outer electrode. One end of the vacuum seal is connected to the ionization tube, and the other end is connected to the mass spectrometer sample injection end. The sample injection pipeline is used to transport carrier gas or samples. The inner electrode, the ... The ionization system composed of the outer electrode, the high-voltage AC power supply and the ionization tube is used to generate plasma. The inner electrode is a hollow metal tube. The sample is introduced into the internal channel formed by the inner electrode, and the carrier gas is introduced into the external pipeline formed between the inner electrode and the ionization tube. The carrier gas is ionized when passing through the ionization tube area. The sample that only passes through the inner electrode is secondary ionized at the vacuum seal with electrons, ions, metastable particles, etc. drifting from the plasma area, and the sample ions are more efficiently transmitted to the mass spectrometer for detection under the low-pressure environment generated by the vacuum seal.

[0016] A mass spectrometry detection system comprises the device for sample injection and ionization on a mass spectrometer and a mass spectrometer used in conjunction with the device.

[0017] Beneficial technical effects of the present invention:

[0018] The present invention provides a device for ionization injection of a mass spectrometer, wherein the sample to be detected passes through the injection pipeline, enters the ionization tube, passes through the plasma zone to be ionized or is secondary ionized in the vacuum seal, and finally enters the mass spectrometer for detection. The injection ionization device of the present invention can effectively prevent interference from impurities in the environment such as the air background, improve the transmission efficiency and ionization efficiency of the sample to be tested, and improve the transmission efficiency of ions through a simple and ingenious structural design, thereby increasing the detection signal intensity, reducing the detection limit, and improving stability. In addition, the device can realize self-priming injection by utilizing the air pressure difference without other auxiliary methods.

[0019] The present invention can realize the detection of carrier gas alone; it can also realize the detection of gas sample alone, and can detect carrier gas and gas sample simultaneously, thus providing a more effective sampling and ionization method for the analytical instrument field. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of a device for mass spectrometer sample injection ionization according to an embodiment of the present invention

[0021] Figure 2 The diagram is a schematic diagram of the structure of a mass spectrometry detection system composed of a device and a mass spectrometer according to an embodiment of the present invention.

[0022] Figure 3 It is a structural schematic diagram of a mass spectrometry detection system composed of a device and a mass spectrometer according to another embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following is a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0024] like Figure 1 and Figure 2 As shown, in one embodiment, a device for mass spectrometer sample injection and ionization includes a sample injection pipeline 1, a sealing coupling 2, a high-voltage AC power supply 3, an inner electrode 4, an outer electrode 5, an ionization tube 6, a vacuum seal 7, and a mass spectrometer 8. The sample injection pipeline 1 is connected to the ionization tube 6 through the sealing coupling 2, the inner electrode 4 is placed in the ionization tube 6, preferably located in the center of the ionization tube 6, the outer electrode ring 5 is wrapped around the outer surface of the ionization tube 6, the high-voltage AC power supply 3 is connected between the inner electrode 4 and the outer electrode 5, one end of the vacuum seal 7 is connected to the ionization tube 6, and the other end is connected to the sample injection port of the mass spectrometer 8. The sample inlet line 1 is used to transport carrier gas or sample, and the ionization system composed of the inner electrode 4, the outer electrode 5, the high-voltage AC power supply 3 and the ionization tube 6 is used to generate plasma. The sample enters the ionization tube 6, and a part of the sample passes through the plasma zone generated in the ionization tube 6 and is ionized, and the remaining sample reacts with electrons, ions, metastable particles, etc. drifting from the plasma zone at the vacuum seal 7 to generate secondary ionization. At the same time, the sample ions are more efficiently transmitted to the mass spectrometer 8 for detection under the low-pressure environment generated by the vacuum seal 7. Among them, the sample can be blown into the ionization tube 6 by the carrier gas, or the sample gas can be self-absorbed or pumped into the ionization tube 6, and the present invention does not limit this.

[0025] like Figure 3As shown, in another embodiment, different from the previous embodiment, in this embodiment, the sample is introduced into the internal channel formed by the inner electrode 4, and the carrier gas (such as helium, argon, nitrogen) is introduced into the external pipeline formed between the inner electrode 4 and the ionization tube 6. The carrier gas is ionized when passing through the ionization tube 6 area, and the sample that only passes through the inner electrode 4 is secondary ionized at the vacuum seal 7 with electrons, ions, metastable particles, etc. drifting from the plasma area, and the sample ions are more efficiently transmitted to the mass spectrometer 8 for detection under the low pressure environment generated by the vacuum seal 7.

[0026] In the device for sample injection and ionization of a mass spectrometer of the present invention, a vacuum seal is provided between the ionization tube and the injection port of the mass spectrometer. During operation, a portion of the sample can be ionized directly through the plasma region in the ionization tube, or the sample can be ionized only through the inner electrode. In both cases, the unionized sample will be secondary ionized at the vacuum seal with electrons, ions, metastable particles, etc. drifting from the plasma region, thereby further improving the ionization efficiency. In addition, the low-pressure environment generated by the vacuum seal helps the sample ions to be more efficiently transmitted to the mass spectrometer, reduces the loss and interference of ions during the transmission process, and improves the detection efficiency of ions.

[0027] Due to the above design, the device for mass spectrometer sample injection and ionization of the present invention can effectively improve the ionization efficiency of the sample to be tested, prevent interference from impurities in the environment, and improve the transmission efficiency of sample ions, thereby improving the detection signal intensity, reducing the detection limit, and improving stability; the device can also use the gas pressure difference to achieve self-priming injection without other auxiliary methods.

[0028] In a preferred embodiment, the inner electrode 4 is a hollow metal tube with an inner diameter of (1 mm, 5 mm], more preferably, its inner diameter is 2 mm; the inner diameter of the ionization tube 6 is (1 mm, 10 mm], and the outer diameter is (3 mm, 15 mm], more preferably, its inner diameter is 3 mm, and the outer diameter is 5 mm.

[0029] In a preferred embodiment, the distance between the outer surface of the inner electrode 4 and the inner wall of the ionization tube 6 is (0.1 mm, 5 mm], and more preferably, the distance is 1 mm.

[0030] In a preferred embodiment, the output voltage of the AC high-voltage power supply is (3 kV, 20 kV], more preferably, its output voltage is 4 kV; the output frequency of the AC high-voltage power supply is (10 kHz, 100 kHz], more preferably, its voltage is (20 kHz, 25 kHz].

[0031] In a preferred embodiment, the cross-sectional shape of the ionization tube 6 is a hollow circular ring, and the lengths of the inner electrode 4 and the outer electrode 5 are (0.5 mm, 200 mm]. The range and volume of the plasma zone can be regulated by controlling the overlap length of the inner electrode 4 and the outer electrode 5 in the axial direction of the ionization tube 6, thereby controlling the number and type of sample ions generated. Preferably, the overlap length is (50 mm, 200 mm).

[0032] In a preferred embodiment, the angle between the sample injection pipeline 1 and the ionization tube 6 is (90°, 180°], more preferably, the angle is 180 degrees, and the angle between the vacuum seal 7 and the ionization tube 6 is (90°, 180°], more preferably, the angle is 180 degrees.

[0033] In a preferred embodiment, the air pressure in the sealed cavity formed by the sample injection pipeline 1, the ionization tube 6, and the vacuum seal 7 is lower than a standard atmospheric pressure, the carrier gas and the sample enter the ionization tube 6 through a pump, or enter the ionization tube 6 by self-absorption using the pressure difference, and the sample ions to be entered into the mass spectrometer enter the mass spectrometer through the vacuum seal 7 by self-absorption using the pressure difference or driven by the airflow.

[0034] In a preferred embodiment, the ionization tube 6 is a quartz glass tube or a ceramic tube, and the vacuum seal 7 is made of polyetheretherketone (PEEK) or nylon material.

[0035] In a preferred embodiment, the carrier gas is air, helium, argon, nitrogen, etc., more preferably, it is air.

[0036] like Figure 2 As shown, in one embodiment, a mass spectrometry detection system includes the device for mass spectrometer sample injection ionization and a mass spectrometer 8 used in conjunction with the device. The mass spectrometer 8 can be an ion trap mass spectrometer or a quadrupole mass spectrometer. The mass spectrometer 8 can include a vacuum chamber 9, an ion trap mass analyzer 10, and a detector 11.

[0037] The specific embodiments of the present invention, its principles and advantages are further described below in conjunction with the accompanying drawings.

[0038] like Figure 2As shown, a device for mass spectrometer sample injection and ionization includes a sample injection pipeline 1, a sealing coupling 2, a high-voltage AC power supply 3, an inner electrode 4, an outer electrode 5, an ionization tube 6, a vacuum seal 7, and a mass spectrometer 8. The sample injection tube 1 is connected to the ionization tube 6 through the sealing coupling 2, the inner electrode 4 is placed in the center of the ionization tube 6, the outer electrode ring 5 is wrapped around the outer surface of the ionization tube 6, the high-voltage AC power supply 3 is connected between the inner electrode 4 and the outer electrode 5, one end of the vacuum seal 7 is connected to the ionization tube 6, and the other end is connected to the sample injection port of the mass spectrometer 8. The sample inlet line 1 is used to transport carrier gas or samples. The ionization system composed of the inner electrode 4, the outer electrode 5, the high-voltage AC power supply 3 and the ionization tube 6 can generate a non-equilibrium plasma for ionizing samples. The sample enters the ionization tube 6, and a part of the sample passes through the plasma zone generated in the ionization tube 6 and is ionized. The remaining sample reacts with electrons, ions, metastable particles, etc. drifting from the plasma zone at the vacuum seal 7 to generate secondary ionization. The sample ions are more efficiently transmitted to the mass spectrometer 8 for detection under the low-pressure environment generated by the vacuum seal 7. Figure 3 As shown, the sample can also be introduced into the internal channel formed by the inner electrode 4, the carrier gas is ionized through the ionization tube 6 area, and the sample that only passes through the inner electrode 4 is secondary ionized at the vacuum seal 7 with electrons, ions, metastable particles, etc. drifting from the plasma region.

[0039] Through the device, for the sample to be detected, the transmission efficiency of the sample and ions can be improved by controlling the sealing performance of the vacuum seal, so that more sample ions can enter the mass spectrometer, and the injection efficiency and detection efficiency can be improved; the isolation of the vacuum seal can prevent impurities in the ambient air from interfering with the experimental results; the range and volume of the generated plasma can be controlled by adjusting the overlap length of the inner and outer electrodes on the ionization tube, the volume density of electrons, ions, and metastable ions can be increased, and the possibility of sample ions being ionized can be increased, thereby improving the signal strength of the sample to be detected.

[0040] It is worth noting that the present invention does not limit the specific implementation and control method of this injection and ionization method.

[0041] Those skilled in the art will recognize that numerous variations to the above description are possible, and that the examples are intended only to describe one or more specific implementations.

[0042] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A device for mass spectrometer sample injection ionization, characterized in that, The invention comprises an injection pipeline, a high-voltage AC power supply, a sealing coupling, an outer electrode, an inner electrode, an ionization tube, and a vacuum seal. The injection pipeline is connected to the ionization tube through a seal. The inner electrode is placed in the ionization tube, preferably in the center of the ionization tube. The outer electrode surrounds the outside of the ionization tube. The high-voltage AC power supply is connected between the inner electrode and the outer electrode. One end of the vacuum seal is connected to the ionization tube, and the other end is connected to the mass spectrometer injection end. The injection pipeline is used to transport carrier gas or samples. The ionization system composed of the inner electrode, the outer electrode, the high-voltage AC power supply and the ionization tube is used to generate plasma. When the sample enters the ionization tube, a part of the sample passes through the plasma zone generated in the ionization tube and is ionized. The remaining sample is secondary ionized at the vacuum seal with electrons, ions, metastable particles, etc. drifting from the plasma zone. The sample ions are more efficiently transmitted to the mass spectrometer for detection under the low-pressure environment generated by the vacuum seal.

2. The device according to claim 1, characterized in that The inner electrode is a hollow metal tube with an inner diameter of (1mm, 5mm], preferably, its inner diameter is 2mm; the inner diameter of the ionization tube is (1mm, 10mm], and the outer diameter is (3mm, 15mm], preferably, its inner diameter is 3mm, and the outer diameter is 5mm; the distance between the outer surface of the inner electrode and the inner wall of the ionization tube is (0.1mm, 5mm], preferably, the distance is 1mm.

3. The device according to any one of claims 1 to 3, characterized in that The cross-sectional shape of the ionization tube is a hollow circular ring, the length of the inner electrode is (0.5 mm, 200 mm], and the length of the outer electrode is (0.5 mm, 200 mm]. The range and volume of the plasma zone can be regulated by controlling the overlap length of the inner electrode and the outer electrode in the axial direction of the ionization tube, thereby controlling the number of sample ions generated. Preferably, the overlap length is (50 mm, 200 mm].

4. The device according to any one of claims 1 to 4, characterized in that The output voltage of the AC high-voltage power supply is (3kV, 20kV], preferably, its output voltage is 4kV; the output frequency of the AC high-voltage power supply is (10kHz, 100kHz], preferably, its output frequency is (20kHz, 25kHz].

5. The device according to any one of claims 1 to 5, characterized in that The angle between the injection pipeline and the ionization tube is (90°, 180°], preferably, the angle is 180°, the angle between the vacuum seal and the ionization tube is (90°, 180°], preferably, the angle is 180°, and the three are in the same straight line with the central axis of the mass spectrometer injection port.

6. The device according to any one of claims 1 to 6, wherein the air pressure in the sealed cavity formed by the sample injection pipeline, the ionization tube, and the vacuum seal is lower than a standard atmospheric pressure, the carrier gas or sample enters the ionization tube through a pump, or enters the ionization tube by self-absorption using the pressure difference, and the sample ions to be entered into the mass spectrometer enter the mass spectrometer through the vacuum seal by self-absorption using the pressure difference or driven by the airflow.

7. The device according to any one of claims 1 to 7, characterized in that The ionization tube is a quartz glass tube or a ceramic tube, and the vacuum seal is made of polyetheretherketone (PEEK) or nylon material.

8. The device according to any one of claims 1 to 8, characterized in that The carrier gas is air, helium, argon, nitrogen, etc. Preferably, it is air.

9. A device for mass spectrometer sample injection ionization, characterized in that: The invention comprises an injection pipeline, a high-voltage AC power supply, a sealing coupling, an outer electrode, an inner electrode, an ionization tube, and a vacuum seal. The injection pipeline is connected to the ionization tube through a seal. The inner electrode is placed in the ionization tube, preferably in the center of the ionization tube. The outer electrode surrounds the outside of the ionization tube. The high-voltage AC power supply is connected between the inner electrode and the outer electrode. One end of the vacuum seal is connected to the ionization tube, and the other end is connected to the mass spectrometer injection end. The injection pipeline is used to transport carrier gas or samples. The inner electrode, the outer electrode, the high-voltage AC power supply are connected to the ionization tube, and the other end is connected to the mass spectrometer injection end. The ionization system composed of a high-voltage AC power supply and the ionization tube is used to generate plasma, the inner electrode is a hollow metal tube, the sample is introduced into the internal channel formed by the inner electrode, the carrier gas is introduced into the external pipeline formed between the inner electrode and the ionization tube, the carrier gas is ionized when passing through the ionization tube area, the sample that only passes through the inner electrode is secondary ionized at the vacuum seal with electrons, ions, metastable particles, etc. drifting from the plasma area, and the sample ions are more efficiently transmitted to the mass spectrometer for detection under the low-pressure environment generated by the vacuum seal.

10. A mass spectrometry detection system, characterized in that: The invention comprises a device for sample injection and ionization of a mass spectrometer as claimed in any one of claims 1 to 9 and a mass spectrometer used in conjunction with the device.

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