Real-time direct analysis mass spectrum ion source device
By introducing normal ballast gas into the glass cavity and establishing a potential difference, metastable substances are generated to achieve sample ionization, the cost of existing DART ion source devices is solved, and low-cost and efficient sample ionization is achieved.
Patent Information
- Application Number
- CN202411468306.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-03-04
AI Technical Summary
The existing DART ion source devices are expensive, increasing scientific research costs and hindering their application in more fields.
An economical and simple real-time direct analysis mass spectrometry ion source device is designed. By introducing normal ballast gas into the glass cavity and establishing potential difference, a neutral excited substance in metastable state is generated, and the interaction between carrier gas and reaction gas is used to generate ionized derivatives to achieve ionization of the sample.
Low-cost ionization of samples under normal temperature and pressure is achieved, reducing the production and use costs of the device, simplifying the process, and improving the durability and reliability of the device.
Smart Images
Figure CN119560369A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an economical and simple real-time direct analysis mass spectrometer ion source device, belonging to the technical field of ion sources. Background Art
[0002] Mass spectrometry is an analytical method with fast detection speed, small sample amount and high sensitivity. It is increasingly widely used in chemical engineering, clinical analysis, and subject research. In order to better meet the needs of modern society for mass spectrometry, the development and design of ion sources with advantages such as wide application range, high durability, and simple operation has become one of the focuses of mass spectrometry research. The successful development of the direct analysis in real time (DART) ion source makes up for the shortcomings of conventional atmospheric pressure ionization technologies such as electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI), which require sample dissolution and desalination, as well as sample and matrix mixing and co-crystallization, making it difficult to achieve rapid and large-scale analysis and screening of substances, making direct analysis without sample preparation possible. With its own advantages, the DART ion source has played a significant role in biological detection, drug detection, environmental analysis, and other fields. However, the price of the DART ion source currently available on the market is relatively expensive, which increases the research cost of scientific research and hinders the application of the DART ion source in more fields. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide an economical and simple real-time direct analysis mass spectrometry ion source device, which can realize the ionization of samples at room temperature and pressure at a relatively low cost.
[0004] The principle of the method implemented by the present invention is: introducing a normal pressure carrier gas into a glass cavity, and establishing a potential difference in the cavity, thereby generating a metastable neutral excited state substance. The carrier gas and the metastable substance are conducted from the cavity to the reaction gas at atmospheric pressure, wherein the metastable substance interacts with the reaction gas to produce an ionized derivative of the reaction gas. The carrier gas, the reactant gas, and the ionized derivative mixture are guided to contact the analyte under normal pressure and temperature conditions to form analyte ions, analyte fragment ions, and analyte adduct ions. The carrier gas can be composed of one or more of nitrogen and rare gases, and the carrier gas needs to have a metastable state with sufficiently high energy to achieve ionization of the reactant gas. The chamber described in the present invention includes a high-voltage electrode and a ground electrode, and there should be a potential between the high-voltage electrode and the ground electrode that can induce carrier gas discharge.
[0005] Based on the above description, the technical solution adopted by a real-time direct analysis mass spectrometry ion source device provided by the present invention is, including a glass cavity, a high-voltage electrode, a gas inlet, a ground electrode, a filter electrode, and a clamping device. The front end of the glass cavity is an exit for atoms or molecules in a tip excited state. At the tail of the glass cavity, a high-voltage electrode is inserted and fixed, which is connected to a DC power supply through a high-voltage wire. A DC voltage is passed during operation, and an additional resistor is connected to limit the working current. Near the tail position, it is a gas inlet, and high-purity helium with a fixed flow rate is connected during operation. Below the gas inlet is a ground electrode, which is connected to the ground wire by a wire during operation. The side of the ground electrode away from the tail is a filter electrode, which adds a DC voltage or is grounded according to the actual working situation. During operation, discharge will occur between the high-voltage electrode and the ground electrode to produce metastable substances.
[0006] The glass cavity described in the present device is drawn from borosilicate glass, has a length of 110 mm, a diameter of 2 mm at the tip gas outlet, and then uniformly widens to 12.7 mm and maintains this diameter to the tail. The glass cavity as a whole is a fully transparent structure, and the gas ionization during operation can be directly observed, and whether there is a gas leak can be determined by color changes to allow air to mix in.
[0007] After all electrodes described in the device are inserted into the corresponding entrances of the glass cavity, the glass is melted until it is completely fitted with the electrodes, and then cooled and shaped to achieve the purpose of fixing the electrodes, and the electrodes are insulated by insulating tape.
[0008] The gas inlet in the glass cavity of the device has an outer diameter of 4mm and an inner diameter of 2mm. The gas inlet is connected to a polytetrafluoroethylene hose, and the other end of the polytetrafluoroethylene hose is connected to a helium cylinder with a purity of 99.995%. A gas flow meter is connected in front of the gas inlet to control the gas flow rate at 1.5L / min.
[0009] The high-voltage electrode described in this device is a tungsten needle electrode with a diameter of 1mm and a length of 20mm. When in use, it is connected to a DC high-voltage power supply with an input voltage of 1.5-2.5kV. At the same time, a protective resistor with a resistance value of 10MΩ is connected to control the current at 0.1-0.2mA.
[0010] The grounding electrode described in this device is a tungsten needle electrode with a diameter of 1mm and a length of 20mm. It is connected to the ground wire when in use. When the high-voltage electrode is connected to high voltage, glow discharge will be stimulated between the high-voltage electrode and the grounding electrode, causing the gaseous helium atoms to become excited, forming a plasma of ions, electrons and excited gas in the glass cavity.
[0011] The filter electrode described in the device is located between the ground electrode and the gas outlet. The filter electrode is a tungsten needle electrode with a diameter of 1 mm and a length of 20 mm. The filter electrode selectively filters ions with opposite polarity to the target by adding voltage, and prevents ion-ion and ion-electron recombination, allowing only long-lived electron excited state atoms or molecules to enter the next cavity and be emitted from the gas outlet to the sample surface.
[0012] The clamping device described in the device is composed of a three-claw clamp and an iron frame. The glass cavity is clamped by the three-claw clamp, and the three-claw clamp is fixed on the iron frame. By adjusting the angle of the three-claw clamp, the glass cavity is 45° with the horizontal direction. By adjusting the relative position of the three-claw clamp and the glass cavity, the distance between the sample and the tip outlet and the mass spectrometer injection port is no more than 5 mm.
[0013] Compared with other DART devices, this device has the following features:
[0014] The device has a low manufacturing cost and has great advantages over the DART ion source on the market. The manufacturing process of the device is simple and can be quickly mass-produced. There are no technical difficulties in the use of the device, which reduces the threshold for experimental personnel to learn and master the technology and has wide commercial value. The device is small in size, light in weight, easy to carry and easy to keep. In addition, the device is an integrated structure, which can directly analyze the mass spectrometry ion source in real time, is not prone to failure, has a low loss rate, and can be used for a long time. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a schematic diagram of an economical and simple real-time direct analysis mass spectrometry ion source device.
[0016] In the figure: 1. Glass cavity; 2. Gas inlet; 3. High voltage electrode; 4. Ground electrode; 5. Filter electrode; 6. Gas outlet. DETAILED DESCRIPTION
[0017] An economical and simple real-time direct analysis mass spectrometry ion source device is further described in detail below in conjunction with the accompanying drawings.
[0018] Figure 1The following components of an economical and simple real-time direct analysis mass spectrometry ion source device are shown: a glass cavity 1, a gas inlet 2, a high-voltage electrode 3, a ground electrode 4, a filter electrode 5, and a gas outlet 6. The glass cavity 1 is made of borosilicate glass, with a smooth and transparent appearance and a total length of 110 mm. Near the tail is the gas inlet 2, which has an outer diameter of 4 mm and an inner diameter of 2 mm. It is connected to an external gas path, and the gas is passed into the glass cavity 1. The gas composition is 99.995% helium, and the flow rate is 1.5 L / min. After the gas fills the glass cavity 1, the high-voltage electrode 3 is connected to the DC power supply through a high-voltage wire, and a DC voltage of 1.5-2.5 kV is input. A 10 MΩ resistor is connected in series between the high-voltage power supply and the high-voltage electrode 3 through a wire, and the working current is controlled at 0.1-0.2 mA. When voltage is applied, the electric field between the high-voltage electrode 3 and the ground electrode 4 causes the helium to glow discharge, and the metastable substances such as electron ions formed by the discharge will flow toward the gas outlet 6 of the glass cavity 1 along with the airflow. The filter electrode 5 is located between the gas outlet 6 and the ground electrode 4, and its purpose is to filter out short-lived ions. The voltage of the filter electrode 5 can be 0V (i.e. grounded) or a voltage of several hundred volts with the opposite polarity to that of the high-voltage electrode can be applied as needed. The metastable molecules filtered by the filter electrode 5 flow toward the gas outlet 6 under the action of air pressure. The diameter at the gas outlet 6 is 2mm, and then the diameter is uniformly widened to 12.7mm, and the diameter is maintained to the tail.
[0019] The clamping device of the present invention is composed of a common three-claw clamp and an iron frame, and the glass cavity (1) is clamped by the three-claw clamp, and the three-claw clamp is fixed on the iron frame. The position of the glass cavity 1 is adjusted by adjusting the angle of the three-claw clamp, and the angle between the gas outlet 6 and the sample is controlled to be about 45°, and the distance between the sample and the mass spectrometer injection port and the gas outlet 6 is about 5 mm, and fine-tuning is continuously performed until a stable mass spectrometer signal is collected.
[0020] After the high-voltage electrode of the present invention is connected to high-voltage electricity, glow discharge will be stimulated between the high-voltage electrode and the ground electrode to produce metastable substances, which will be filtered by the filter electrode and then ejected from the front end of the glass cavity to the sample surface to achieve ionization of the sample. This device has the advantages of low cost, small size and easy operation. It should be further explained that the above content is an example of an economical and simple real-time direct analysis mass spectrometry ion source device. Technicians in the technical field to which the device belongs can make various modifications, supplements or substitutions within the scope described above, which should all fall within the protection scope of the present invention.
Claims
1. A real-time direct analysis mass spectrometry ion source device, characterized in that: The device comprises a glass cavity (1), a high-voltage electrode (3), a gas inlet (2), a grounding electrode (4), a filter electrode (5), and a clamping device. A high-voltage electrode (3) is inserted and fixed at the tail of the glass cavity (1), connected to a DC power supply via a high-voltage wire, a DC voltage is passed during operation, and a resistor is additionally connected to limit the operating current. The gas inlet (2) is located near the tail, and high-purity helium gas with a fixed flow rate is connected during operation. The grounding electrode (4) is located below the gas inlet (2), and is connected to a ground wire via a wire during operation. The side of the grounding electrode (4) away from the tail is a filter electrode (5), which is added with a DC voltage or grounded for use according to the actual working conditions. During operation, discharge occurs between the high-voltage electrode (3) and the grounding electrode (4) to generate metastable substances of excited helium gas.
2. A real-time direct analysis mass spectrometry ion source device according to claim 1, characterized in that: The glass cavity (1) is drawn from borosilicate glass and has a length of 110 mm. The diameter at the tip gas outlet (6) is 2 mm, and then the diameter uniformly widens to 12.7 mm and maintains this diameter to the tail. The glass cavity (1) is a fully transparent structure as a whole, and the gas ionization during operation can be directly observed. Whether there is a gas leak can be determined by color changes to allow air to mix in.
3. A real-time direct analysis mass spectrometry ion source device according to claim 1, characterized in that: After all electrodes are inserted into the corresponding entrances of the glass cavity (1), the glass is melted until it is completely fitted with the electrodes, and then cooled and shaped to achieve the purpose of fixing the electrodes, and the electrodes are insulated using insulating tape.
4. The real-time direct analysis mass spectrometry ion source device according to claim 1, characterized in that: The gas inlet (2) has an outer diameter of 4 mm and an inner diameter of 2 mm. The gas inlet (2) is connected to a polytetrafluoroethylene hose, and the other end is connected to a helium cylinder with a purity of 99.995%. A gas flow meter is connected in front of the gas inlet (2) to control the gas flow rate at 1.5 L / min.
5. The real-time direct analysis mass spectrometry ion source device according to claim 1, characterized in that: The high-voltage electrode (3) is a tungsten needle electrode with a diameter of 1.59 mm and a length of 20 mm. When in use, it is connected to a DC high-voltage power supply with an input voltage of 1.5-2.5 kV. At the same time, a protective resistor with a resistance value of 10 MΩ is connected to control the current to 0.1-0.2 mA.
6. The real-time direct analysis mass spectrometry ion source device according to claim 1, characterized in that: The grounding electrode (4) is a tungsten needle electrode with a diameter of 1 mm and a length of 20 mm. It is connected to the ground wire when in use. When the high-voltage electrode (3) is connected to high voltage electricity, glow discharge is stimulated between the high-voltage electrode (3) and the grounding electrode (4), causing gaseous helium atoms to become excited, and forming a plasma of ions, electrons and excited gas in the glass cavity (1).
7. The real-time direct analysis mass spectrometry ion source device according to claim 1, characterized in that: The filter electrode (5) is located between the ground electrode (4) and the gas outlet (6). The filter electrode (5) is a tungsten needle electrode with a diameter of 1 mm and a length of 20 mm. The filter electrode (5) selectively filters ions with opposite polarity to the target by applying voltage, and prevents ion-ion and ion-electron recombination, allowing only long-lived electron excited state atoms or molecules to enter the next cavity and be emitted from the gas outlet (6) to the sample surface.
8. The real-time direct analysis mass spectrometry ion source device according to claim 1, characterized in that: The clamping device consists of a three-claw clamp and an iron frame. The glass cavity (1) is clamped by the three-claw clamp, and the three-claw clamp is fixed on the iron frame. By adjusting the angle of the three-claw clamp, the glass cavity (1) is made to be 45 degrees with the horizontal direction. By adjusting the relative position of the three-claw clamp and the glass outer tube, the distance between the sample and the tip outlet and the mass spectrometer injection port is no more than 5 mm.