Multi-mode mass spectrometer

Abstract

This invention belongs to the field of mass spectrometry technology, specifically providing a multi-mode mass spectrometer, including an ion source with a first inlet, an ion funnel including multiple electrodes, multiple isolators and a heating element, wherein the isolators are disposed between adjacent electrodes of the ion funnel and are insulated from adjacent electrodes, and the heating element is disposed on the isolators; a second inlet is disposed between the ion source and the ion funnel. This invention has advantages such as strong detection capability, strong anti-contamination capability, and high ion transmission efficiency.

Description

Technical Field

[0001] This utility model relates to mass spectrometry technology, and in particular to a multimode mass spectrometer. Background Technology

[0002] Mass spectrometers, as core tools of modern analytical chemistry, play an irreplaceable role in fields such as environmental monitoring, biomedicine, drug development, and food safety. Their performance directly determines the sensitivity, resolution, and stability of detection, which are closely related to the design of the ion source. The ion source is a key component of a mass spectrometer, responsible for converting sample molecules into gaseous ions and guiding them into the mass analyzer. With the diversification and complexity of analytical needs, the requirements for mass spectrometers are becoming increasingly stringent, especially in the analysis of complex samples (such as high-salt biological samples or samples from high-matrix environments). In these cases, the ion source needs a wide detection range to detect unknown substances. Furthermore, a high-performance transmission system is required to improve transmission efficiency while also possessing excellent anti-contamination properties.

[0003] Currently, most mass spectrometers on the market are typically equipped with only a single ion source, which makes it difficult to meet the analytical needs of multiple types of samples and lacks the ability to quickly switch between different ionization modes.

[0004] If the ion source needs to be replaced, mechanical disassembly or complex adjustments are required, which not only affects experimental efficiency but may also lead to a decrease in the stability of ion transport.

[0005] Furthermore, existing ion transport systems are prone to accumulating contaminants during long-term operation, which affects ion transport efficiency and mass spectrometry sensitivity, leading to signal drift and decreased sensitivity, and affecting the long-term stability of the mass spectrometer. Summary of the Invention

[0006] To address the shortcomings of the existing technical solutions, this utility model provides a multi-mode mass spectrometer.

[0007] The objective of this utility model is achieved through the following technical solution:

[0008] A multimode mass spectrometer includes an ion source and an ion funnel, the ion source having a first opening, and the ion funnel including multiple electrodes; the ion funnel further includes:

[0009] Multiple isolators and heating elements are provided, wherein the isolators are disposed between adjacent electrodes of the ion funnel and are insulated from the adjacent electrodes, and the heating elements are disposed on the isolators;

[0010] A second opening is provided between the ion source and the ion funnel.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0012] 1. It realizes multi-mode operation of a single ion source, expanding the range of detectable substances. In addition to detecting VOCs with a proton affinity greater than that of water, it can also detect other substances with a proton affinity less than that of water, inorganic substances, or substances that cannot be detected due to low mass discrimination.

[0013] 2. By utilizing the heating function on the isolator, the heating ion funnel evaporates the residual sample through temperature control, significantly reducing the memory effect, and is especially suitable for continuous detection of high-boiling-point or viscous samples;

[0014] The insulating component uses an aluminum substrate, which provides better heat dissipation uniformity than traditional stainless steel structures, thus avoiding ion fragmentation caused by localized overheating.

[0015] The heating function increases the kinetic energy of ions, and combined with the focusing effect of the closed funnel, the ion transport efficiency is improved. Attached Figure Description

[0016] The disclosure of this utility model will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are merely illustrative of the technical solutions of this utility model and are not intended to limit the scope of protection of this utility model. In the drawings:

[0017] Figure 1 This is a schematic diagram of the mass spectrometer of this utility model;

[0018] Figure 2 This is a diagram comparing transmission efficiency;

[0019] Figure 3 This is a diagram comparing pollution resistance capabilities. Detailed Implementation

[0020] Figures 1-3 The following description illustrates optional embodiments of the present invention to teach those skilled in the art how to implement and reproduce it. For the purpose of teaching the technical solutions of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art should understand that variations or substitutions derived from these embodiments will be within the scope of the present invention. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the present invention. Therefore, the present invention is not limited to the following optional embodiments, but is defined only by the claims and their equivalents.

[0021] Example 1

[0022] The multi-mode mass spectrometer of Embodiment 1 of this utility model, such as Figure 1 As shown, the mass spectrometer includes:

[0023] The ion source consists of five stainless steel electrodes. The first electrode 1 is a disc with a length of 2-4 mm. The second electrode 2 is cylindrical with a length of 8-20 mm and a thickness of 2-3 mm. The third electrode 3 is also a disc with a length of 2-4 mm, but with a central aperture that increases in size from 1-2 mm to 6-8 mm along the ion transport direction. The fourth electrode 4 is identical to the second electrode 2. The fifth electrode 5 is a skimmer structure with a length of 5-8 mm and an opening angle of 50°-80°. All five electrodes are coaxial and have the same radius of 15-20 mm, with a spacing of 8-12 mm between them. A positive voltage ranging from 100V to 200V is applied to the first, third, fourth, and fifth electrodes, decreasing progressively, while a negative voltage ranging from -350V to -450V is applied to the second electrode 2. The first opening 9 is positioned between the first and second electrodes.

[0024] The ion funnel includes multiple electrodes 6, separators 7, and a heating element. Each electrode 6 has a thickness of 1-2 mm. The separators 7, also 1-2 mm thick, are positioned between adjacent electrodes 6 and are insulated from each other, with an insulating layer between them. The heating element is mounted on the separators 7 and is insulated from the electrodes 6. The heating element uses copper wire with a resistance between 0.5 Ω and 2 Ω. It heats up when energized, thus enabling the ion funnel to be sealed and heated, reducing interference from external airflow. Simultaneously, the heated ion funnel provides kinetic energy to the ions, improving transport efficiency and making them more active, preventing residual contamination on the ion funnel.

[0025] Along the ion transport direction, the ion funnel includes a portion with a constant inner diameter and a portion with a reduced inner diameter, each consisting of multiple electrodes 6 and spacers 7.

[0026] The second opening 10 is located between the fifth electrode 5 and the portion with a constant inner diameter. The solenoid valve is connected to the second opening 10, so that when the solenoid valve is closed, the second opening 10 is closed, and when the solenoid valve is open, the analyte enters the mass spectrometer through the second opening 10.

[0027] A skimmer lens 8 is used to connect the end of the ion funnel to the ion trap mass spectrometer. The skimmer lens has an opening angle of 50° to 80° and a total length of 4 to 6 mm. This lens structure can improve the focusing effect of ions. A third opening 11 is set between the end of the ion funnel and the lens 8 to introduce a buffer gas, such as nitrogen, helium, argon or air.

[0028] The ion source has two operating modes:

[0029] Mode 1: Water vapor is introduced through the first opening 9, sample gas is introduced through the second opening 10, and buffer gas is introduced through the third opening 11. VOCs with a proton affinity greater than that of water can be detected in this mode. However, some substances may not be detectable due to their proton affinity being less than that of water, their classification as inorganic substances, or low-mass discrimination. In such cases, the mode can be switched to Mode 2.

[0030] Mode 2: No water vapor is introduced through the first opening 9. The sample is introduced through the first opening 9, the second opening 10 is closed, and a buffer gas is introduced through the third opening 11. This mode can detect substances that cannot be detected due to their proton affinity being less than that of water, their inorganic nature, or low mass discrimination, but the detection performance is poor.

[0031] Example 2

[0032] Application example of the multi-mode mass spectrometer according to Embodiment 1 of this utility model.

[0033] In this application example, such as Figure 1 As shown, in the ion source, the first electrode 1 is a disk with a length of 3 mm. The second electrode 2 is cylindrical with a length of 12 mm and a radial thickness of 2 mm. The third electrode 3 is a disk with a length of 3 mm, but with a circular through-hole in the center whose diameter increases from 2 mm to 8 mm along the ion transport direction. The fourth electrode 4 is identical to the second electrode 2. The fifth electrode 5 is a second ion lens, using a skimmer structure, with a length of 6 mm and an opening angle of 70°. The five electrodes are coaxial, have the same radius of 20 mm, and are spaced 10 mm apart.

[0034] The first electrode 1 is applied with a positive voltage of 160V, the second electrode 2 is applied with a negative voltage of 400V, the third electrode 3 is applied with a positive voltage of 150V, the fourth electrode 4 is applied with a positive voltage of 140V, and the fifth electrode 5 is applied with a positive voltage of 130V.

[0035] A switching module, such as a three-way solenoid valve, is connected at the first opening 9 to selectively allow water vapor and the gas to be tested to enter through the first opening 9.

[0036] The ion funnel consists of 27 PCB electrodes 6, each 1mm thick. The first 6 electrodes 6 have an aperture of 16mm, while the aperture of the remaining 21 electrodes gradually decreases to 3.5mm. Adjacent electrodes 6 are separated by spacers 7, which are made of a metal substrate, such as an aluminum substrate, and are 1.2mm thick. The spacers 7 have the same size as the electrodes 6, with an aperture of 17mm. Heating wires, such as copper wires, are distributed on the aluminum substrates, controlling the total resistance to 1Ω. The side with the copper wires should be in contact with the side of the electrode without components to prevent interference from heating. Each aluminum substrate is connected by jumpers, and heating is achieved when energized using a 24V power supply. This enables the ion funnel to be sealed and heated, reducing interference from external airflow. The heated ion funnel provides kinetic energy to the ions, improving transport efficiency and making the ions more active, thus preventing residual contamination on the ion funnel.

[0037] The end of the ion funnel is connected to the ion trap mass spectrometer using a first ion lens, such as a skimmer lens 8, with an opening angle of 70° and a width of 6 mm.

[0038] For the detection of positional samples, the mass spectrometer operates in the following modes:

[0039] First, use mode 1 for detection. Water vapor is introduced through the first opening 9, the gas to be tested is introduced through the second opening 10, and the buffer gas nitrogen is introduced through the third opening 11.

[0040] If the mass-to-charge ratio can be obtained from the mass spectrum, the substance can be analyzed. If no substance can be detected, switch to mode 2. Before switching, remove any excess water vapor from the instrument.

[0041] In Mode 2, water vapor is not introduced through the first opening 9; instead, the gas sample to be tested is introduced. The second opening 10 is closed, while the third opening 11 still introduces the buffer gas, nitrogen. Formaldehyde, which is undetectable due to low-quality discrimination, can be detected in this mode.

[0042] Comparative example:

[0043] The sample to be tested was determined to be 100 ppbv acetone. Mode 1 was used for detection. Water vapor was introduced through the first opening (opening 9), and acetone was introduced through the second opening (opening 10). While keeping other conditions constant, a conventional ion funnel and a closed, heatable ion funnel were used to transfer the substance. The comparison results are as follows: Figure 2 As shown, the heatable ion funnel of this patent improves the transmission efficiency by 20%.

[0044] Anti-contamination capability was tested by continuously injecting acetone samples for 1 hour at a flow rate of 10 ml / min, followed by rinsing the mass spectrometer with carrier gas for 5 hours. Then, the mass spectrometer was turned on without introducing any sample, and the residual acetone signal was observed. The comparison results are as follows: Figure 3 As shown, the closed, heatable ion funnel of the present invention has five times the anti-fouling ability of a traditional ion funnel.

Claims

1. A multi-modal mass spectrometer comprising an ion source having a first opening and an ion funnel comprising a plurality of electrodes; characterised in that, The ion funnel also includes: Multiple isolators and heating elements are provided, wherein the isolators are disposed between adjacent electrodes of the ion funnel and are insulated from the adjacent electrodes, and the heating elements are disposed on the isolators; A second opening is provided between the ion source and the ion funnel.

2. The multimode mass spectrometer according to claim 1, characterized in that, The insulating component is made of a metal substrate, and the heating component is made of a heating wire.

3. The multimode mass spectrometer according to claim 2, characterized in that, An insulating layer is provided between the isolator and the adjacent electrode.

4. The multimode mass spectrometer according to claim 1, characterized in that, The mass spectrometer also includes: A switching module is used to selectively connect water vapor and the analyte to the first opening.

5. The multimode mass spectrometer according to claim 1, characterized in that, The mass spectrometer also includes: A first ion lens is disposed downstream of the ion funnel, and a third opening is provided between the ion funnel and the first ion lens.

6. The multimode mass spectrometer according to claim 5, characterized in that, The ion source includes a first electrode, a second electrode, a third electrode, a fourth electrode, and a fifth electrode arranged sequentially. The first and third electrodes are disc-shaped, the third electrode has a through hole that allows ions to pass through, the second and fourth electrodes are cylindrical, and the fifth electrode is a second ion lens. The first opening is disposed between the first electrode and the second electrode, and the second opening is disposed between the fifth electrode and the ion funnel.

7. The multimode mass spectrometer according to claim 6, characterized in that, The first or second ion lens adopts a skimmer structure.

8. The multimode mass spectrometer according to claim 6, characterized in that, The power supply applies a positive voltage to the first, third, fourth, and fifth electrodes, and a negative voltage to the second electrode.

9. The multimode mass spectrometer according to claim 1, characterized in that, The ion funnel includes a portion with a constant inner diameter and a portion with a reduced inner diameter arranged sequentially along the ion transport direction.

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