Multifunctional mass spectrometry device and method

Abstract

The invention belongs to the field of mass spectrometry, and particularly relates to a multifunctional mass spectrometry device and method, and an ion trap of the mass spectrometry device comprises a first group of electrodes and a second group of electrodes which are arranged left and right, and each electrode is provided with a through hole allowing ions to pass through; the third group of electrodes comprises a plurality of electrodes which are respectively arranged on the upper side and the lower side of the first group of electrodes and the second group of electrodes and are arranged left and right; the fourth group of electrodes includes a plurality of electrodes provided on the front and rear sides of the first and second groups of electrodes, respectively, the plurality of electrodes having slits extending in the left-right direction and allowing ions to pass therethrough; the radio-frequency power supply is used for providing radio-frequency voltage for the third group of electrodes and the fourth group of electrodes, and the direct-current power supply is used for providing direct-current voltage for the first group of electrodes and the second group of electrodes; and the controller is used for adjusting the output voltage of the radio frequency power supply and the direct current power supply. The mass spectrometer has the advantages of small size, multiple functions and the like, and can be applied to mass spectrometry.

Description

Technical Field

[0001] The present invention relates to mass spectrometry technology, and in particular to a multifunctional mass spectrometry device and method. Background Art

[0002] The mass spectrometer is one of the advanced high-end analytical scientific instruments and represents the future development direction of analytical instruments. In many current mass spectrometry fields, ion transmission, storage and mass detection are designed for multiple structures and act independently. The complex structure leads to considerable limitations in the installation, maintenance, manufacturing cost and miniaturization of the mass spectrometer.

[0003] The linear electrostatic trap mass spectrometer in the patent US5880466 of Benner et al. is only used for mass measurement of single highly charged molecular ions generated by electrospray. The independent linear electrostatic trap mass spectrometer has a simple structure, but the mass resolution is only a few hundred, and even the conventional resolution is only a few dozen.

[0004] Scott et al. introduced a linear ion trap system that combines quadrupole curved ion trap, linear quadrupole ion trap, electrostatic linear ion trap and plasma transmission components such as multiple lens electrodes in the article Analytical Chemistry 2013, 85, 5226-5232. The mass resolution of this mass spectrometry system is only about 1000, and the ion optical system is complex and difficult to install and debug. Summary of the invention

[0005] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a multifunctional mass spectrometer.

[0006] The objective of the present invention is achieved through the following technical solutions: A multifunctional mass spectrometer comprises an ion trap and a cooling gas supply unit; the ion trap comprises: A first group of electrodes and a second group of electrodes, each of the first group of electrodes and the second group of electrodes arranged on the left and right has a through hole allowing ions to pass through; the cooling air providing unit provides cooling air for the area between the first group of electrodes and the second group of electrodes; A third group of electrodes, the third group of electrodes comprising a plurality of electrodes respectively arranged on the upper side and the lower side of the first group of electrodes and the second group of electrodes; A fourth group of electrodes, the fourth group of electrodes comprising a plurality of electrodes respectively arranged at the front side and the rear side of the first group of electrodes and the second group of electrodes, the plurality of electrodes respectively having a slit extending in the left-right direction for allowing ions to pass through; A radio frequency power supply and a direct current power supply, wherein the radio frequency power supply is used to provide radio frequency voltage to the third group of electrodes and the fourth group of electrodes, and the direct current power supply is used to provide direct current voltage to the first group of electrodes and the second group of electrodes; A controller is used to adjust the output voltages of the RF power supply and the DC power supply.

[0007] The object of the present invention is also to provide a working method of the multifunctional mass spectrometer, which is achieved by the following technical solutions: A working method of a multifunctional mass spectrometer, the working method comprising: In the ion analysis mode, the radio frequency power supply applies radio frequency voltage to the third group of electrodes and the fourth group of electrodes, and the direct current power supply applies different direct current voltages to the first group of electrodes and the second group of electrodes, and ions entering the area between the first group of electrodes and the second group of electrodes collide with the cooling gas to be decelerated and confined in the area; When the frequency of the alternating voltage applied by the radio frequency power supply to the fourth group of electrodes is the same as the movement frequency of the ions, the ions in the area are emitted from the slits of the fourth group of electrodes.

[0008] Compared with the prior art, the present invention has the following beneficial effects: By integrating multiple functions of ion storage, transmission and mass detection into one device, ions can be analyzed and detected in multiple modes such as ion transmission, ion trap analysis, Fourier transform mass analysis and hybrid analysis. It is an ion trap and ion mass analysis device with high integration, complete performance and miniaturization potential.

[0009] It has a larger ion storage capacity than traditional three-dimensional ion trap devices. It has more diverse ion transmission, storage and detection functions than simple linear ion traps, and has a smaller device size and more diverse application scenarios than Fourier transform ion cyclotron resonance mass spectrometry. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings: Figure 1 It is a schematic structural diagram of the multifunctional mass spectrometer of the present invention.

[0011] In the drawings, 11 is a first group of electrodes, 12 is a second group of electrodes, 100 is a through hole, 21 is a third group of electrodes, 31 is a fourth group of electrodes, and 311 is a slit. DETAILED DESCRIPTION

[0012] Figure 1The following description describes optional specific embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these specific embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional specific embodiments, but is only limited by the claims and their equivalents. Example

[0013] A multifunctional mass spectrometer according to an embodiment of the present invention includes an ion trap, such as Figure 1 As shown, the ion trap includes: A first set of electrodes 11 and a second set of electrodes 12, each of which has a through hole 100 allowing ions to pass through; a cooling air providing unit provides cooling air for the area between the first set of electrodes 11 and the second set of electrodes 12; A third group of electrodes 21, the third group of electrodes 21 includes a plurality of electrodes disposed on the upper side and the lower side of the first group of electrodes 11 and the second group of electrodes 12, respectively; A fourth group of electrodes 31, the fourth group of electrodes 31 comprises a plurality of electrodes respectively arranged at the front side and the rear side of the first group of electrodes 11 and the second group of electrodes 12, the plurality of electrodes respectively having a slit 311 extending along the left-right direction for allowing ions to pass through; A radio frequency power supply and a direct current power supply, wherein the radio frequency power supply is used to provide radio frequency voltage to the third group of electrodes 21 and the fourth group of electrodes 31, and the direct current power supply is used to provide direct current voltage to the first group of electrodes 11 and the second group of electrodes 12; A controller is used to adjust the output voltages of the RF power supply and the DC power supply.

[0014] Furthermore, each electrode of the first group of electrodes 11 and the second group of electrodes 12 is connected in series with a resistor, and the resistor provides voltage division.

[0015] Furthermore, the first group of electrodes 11 and the second group of electrodes 12 are electrode plates, and the third group of electrodes 21 and the fourth group of electrodes 31 are electrode sheets.

[0016] Furthermore, the third group of electrodes 21 and the fourth group of electrodes 31 surround a cylindrical region, the first group of electrodes 11 are arranged at the inlet of the cylindrical region, and the second group of electrodes 12 are arranged at the outlet of the cylindrical region.

[0017] In order to confine ions, further, the first set of electrodes 11 and the second set of electrodes 12 are axially symmetrical.

[0018] In order to realize the Fourier transform mass analysis mode, further, the multifunctional mass spectrometer device also includes: A charge amplifier, the charge amplifier is used to detect the current signal on the third group of electrodes 21; A processing unit is used to perform Fourier transform on the current signal to obtain spectrum and mass spectrum data.

[0019] The working method of the multifunctional mass spectrometer of this embodiment is as follows: In the ion analysis mode, the RF power supply applies RF voltage to the third electrode group 21 and the fourth electrode group 31, and the DC power supply applies different DC voltages to the first electrode group 11 and the second electrode group 12, so that the ions entering the area between the first electrode group 11 and the second electrode group 12 collide with the cooling gas to be decelerated and confined in the area; When the frequency of the alternating voltage applied by the radio frequency power supply to the fourth group of electrodes 31 is the same as the movement frequency of the ions, the ions in the area are emitted from the slits 311 of the fourth group of electrodes 31 .

[0020] In order to realize the Fourier transform mass analysis mode, further, in the Fourier transform mass analysis mode, the RF voltage applied to the third group of electrodes 21 and the fourth group of electrodes 31 is 0, the controller adjusts the output voltage of the DC power supply, and the DC power supply applies unequal DC voltages to the first group of electrodes 11 and the second group of electrodes 12, and the ions are confined in the region and make reciprocating motion in the left and right directions; The charge amplifier detects the image current signal on the third group of electrodes 21; The processing unit performs Fourier transform on the current signal to obtain spectrum and mass spectrum data.

[0021] In order to realize the mixed analysis mode, the Fourier transform mass analysis mode and the ion analysis mode are further performed in sequence.

[0022] In order to confine ions, further, in the ion analysis mode, the same DC voltage is applied to the two axially symmetrical electrodes in the first electrode group 11 and the second electrode group 12 . Example

[0023] An application example of the multifunctional mass spectrometry device and method in Example 1 of the present invention.

[0024] In this application example, Figure 1As shown, the first electrode group 11 and the second electrode group 12 respectively use 5 vertically arranged electrode sheets, the diameter of the through holes on the electrode sheets is 2 mm, the central axes of the 10 through holes are collinear, and the spacing between the electrode sheets is 5 mm. The spacing between adjacent electrodes of the first electrode group 11 and the second electrode group 12 is 50 mm. The electrode sheets of the first electrode group 11 and the electrode sheets of the second electrode group 12 are axially symmetrically distributed, and each electrode sheet is connected in series with a resistor.

[0025] The third group of electrodes 21 includes two isolated horizontal electrode sheets arranged on the upper side of the first group of electrodes 11 and the second group of electrodes 12 and arranged along the left-right direction, and two isolated horizontal electrode sheets arranged on the lower side of the first group of electrodes 11 and the second group of electrodes 12 and arranged along the left-right direction.

[0026] The fourth electrode group 31 includes an electrode sheet disposed vertically behind the first electrode group 11 and the second electrode group 12, and an electrode sheet disposed vertically in front of the first electrode group 11 and the second electrode group 12. Both electrode sheets of the fourth electrode group 31 have slits extending in the left-right direction.

[0027] The third group of electrodes 21 and the fourth group of electrodes 31 surround a cylindrical area. The first group of electrodes 11 are arranged at the inlet of the cylindrical area, and the second group of electrodes 12 are arranged at the outlet of the cylindrical area.

[0028] The radio frequency power supply is used to provide radio frequency voltage to the third group of electrodes 21 and the fourth group of electrodes 31 , and the direct current power supply is used to provide direct current voltage to the first group of electrodes 11 and the second group of electrodes 12 .

[0029] A controller is used to adjust the output voltages of the radio frequency power supply and the direct current power supply so that the ion trap is in different working modes.

[0030] The charge amplifier is used to detect the current signal on the third group of electrodes 21. The processing unit performs Fourier transform on the current signal to obtain spectrum and mass spectrum data.

[0031] The working method of the multifunctional mass spectrometer of this embodiment is as follows: 1. Ion focusing confinement mode.

[0032] For positive ions, the DC voltages of the five electrode sheets of the first electrode group 11 and the second electrode group 12 from the edge to the center of the ion trap are 10V, 7V, 2V, -1V, and 1V, respectively, forming a potential well structure with a symmetrical center low potential. The electric field strength distribution range is 0.4~20V / mm.

[0033] The voltage on the third electrode 21 and the fourth electrode group 31 is 0, so that the first electrode group 11 and the second electrode group 12 are axially symmetrical structures, and the voltage applied to these two groups of electrodes puts the ions in the focusing confinement mode of the ion trap.

[0034] After binding a certain amount of ions, for example, according to the size of the front-end ion flux, it is determined that after 10ms, the output voltage of the DC power supply is adjusted by the controller so that the voltages on each electrode sheet in the second group of electrodes 12 are 0V, -1V, -2V, -3V, -6V, and -7V respectively.

[0035] The ion trap is in the focusing transmission mode, which can control the ions with the required momentum dispersion and optimize the spatial momentum dispersion angle of the ions to be less than 0.05 rad. In this potential distribution structure with a gradient distribution but non-uniform electric field, the electric field with the potential structure first guides the axially injected ions by the gradient field of the first set of electrodes 11. Due to the constraint of the electric field, the ions have a focusing constraint effect in the electric field formed by the first set of electrodes 11 and the second set of electrodes 12, and will have a smaller beam diameter when passing through the second set of electrodes 12.

[0036] Without applying an external magnetic field or an excitation electric field, the spatial focusing of the injected ion beam is achieved by changing the potentials of different electrode sheets in the first group of electrodes 11 and the second group of electrodes 12, thereby reducing the position dispersion and improving the momentum dispersion of the ion beam. At the same time, the energy of the ion beam is regulated to achieve extraction with a target kinetic energy.

[0037] 2. Ion trap mass analysis mode.

[0038] For positive ions, the DC voltages applied to the five electrode sheets from the edge to the center of the ion trap in the first group of electrodes 11 and the second group of electrodes 12 are 10V, 7V, 2V, -1V, and 1V, respectively, forming a symmetrical central low-potential potential well structure, and the electric field strength distribution range is 0.4~20V / mm.

[0039] A radio frequency electric field is simultaneously applied to the electrode sheets of the third electrode group 21 and the fourth electrode group 31 to constrain the injected ions. A collision bath gas is provided in the trap region through a collision cooling gas supply assembly. The bath gas pressure is preferably 0.5 mtorr, so that the ions are decelerated to the lowest point of the potential well and confined in the center of the trap region to achieve ion storage and compression. After the injection time of 3-15 ms, the ion beam is decelerated and converged in the area between the first electrode group 11 and the second electrode group 12 by increasing the voltage on the first electrode group 11. The electric field of the second electrode group 12 reversely decelerates and optimizes the position dispersion of the ion beam after focusing in the trap region. The voltage between the first electrode group 11 and the second electrode group 12 is gradually increased so that the potential well depth reaches 200 eV for single-charged ions, thereby increasing the ion beam density in the storage ion region.

[0040] The resonant emission AC voltage provided by the RF power supply is applied to the fourth set of electrodes 31 to simulate the ion motion frequency in the direction (lateral) of the ion detection system. When the AC frequency applied to the fourth set of electrodes 31 is the same as the motion frequency of the captured ions (depending on their mass number), the ions gain kinetic energy increment. If the applied voltage is high enough or the ions are given enough time, the ions will be ejected from the slit 311. The ion beam is ejected laterally through the slit 311 to the ion beam detection device outside the electrode sheet, such as a continuous channel electron multiplier, to detect the beam intensity of the ion beam of a specific mass number.

[0041] 3. Fourier transform mass analysis mode.

[0042] The third group of electrodes 21 and the fourth group of electrodes 31 do not apply a radio frequency electric field to constrain the injected ions. The controller regulates the DC voltage applied by the DC power supply to the electrode sheets of the first group of electrodes 11 and the second group of electrodes 12 to confine the ions to perform axial reciprocating motion in the axial region of the first group of electrodes 11 and the second group of electrodes 12.

[0043] The image current signals generated on the third group of electrodes 21 during the ion cyclotron motion are collected by a low-noise charge sensitive amplifier connected to the third group of electrodes 21 .

[0044] The data processing system performs Fourier transform and other data processing to obtain spectrum and mass spectrum data.

[0045] Using this working mode for non-destructive testing, the resolution of a single quality inspection can reach 100,000.

[0046] 4. Hybrid analysis mode.

[0047] First, the above-mentioned ion trap mass analysis mode is performed to analyze ions of different masses to determine the relative number of ions of the target mass number injected into the ion trap per unit time, and then the ion injection time is controlled by changing the voltage pulse interval time of the first group of electrodes 11 and the second group of electrodes 12 to constrain the ion beam current within the expected ion injection time.

[0048] The ions are then subjected to Fourier transform mass analysis to specifically detect an adjustable number of ion beams.

Claims

1. A multifunctional mass spectrometer, comprising an ion trap and a cooling gas supply unit; characterized in that: The ion trap comprises: A first group of electrodes and a second group of electrodes, each of the first group of electrodes and the second group of electrodes arranged on the left and right has a through hole allowing ions to pass through; the cooling air providing unit provides cooling air for the area between the first group of electrodes and the second group of electrodes; A third group of electrodes, the third group of electrodes comprising a plurality of electrodes respectively arranged on the upper side and the lower side of the first group of electrodes and the second group of electrodes; A fourth group of electrodes, the fourth group of electrodes comprising a plurality of electrodes respectively arranged at the front side and the rear side of the first group of electrodes and the second group of electrodes, the plurality of electrodes respectively having a slit extending in the left-right direction for allowing ions to pass through; A radio frequency power supply and a direct current power supply, wherein the radio frequency power supply is used to provide radio frequency voltage to the third group of electrodes and the fourth group of electrodes, and the direct current power supply is used to provide direct current voltage to the first group of electrodes and the second group of electrodes; A controller is used to adjust the output voltages of the RF power supply and the DC power supply.

2. The multifunctional mass spectrometer according to claim 1, characterized in that: Each electrode of the first group of electrodes and the second group of electrodes is connected in series with a resistor.

3. The multifunctional mass spectrometer according to claim 1, characterized in that: The first group of electrodes and the second group of electrodes are electrode plates, and the third group of electrodes and the fourth group of electrodes are electrode sheets.

4. The multifunctional mass spectrometer according to claim 1, characterized in that: The third group of electrodes and the fourth group of electrodes surround a cylindrical region, the first group of electrodes is arranged at the inlet of the cylindrical region, and the second group of electrodes is arranged at the outlet of the cylindrical region.

5. The multifunctional mass spectrometer according to claim 1, characterized in that: The first group of electrodes and the second group of electrodes are axially symmetric.

6. The multifunctional mass spectrometer according to claim 1, characterized in that: The multifunctional mass spectrometer also includes: A charge amplifier, the charge amplifier is used to detect the current signal on the third group of electrodes; A processing unit is used to perform Fourier transform on the current signal to obtain spectrum and mass spectrum data.

7. The working method of the multifunctional mass spectrometer according to claim 1, wherein the working method comprises: In the ion trap mass analysis mode, the RF power supply applies RF voltage to the third group of electrodes and the fourth group of electrodes, and the DC power supply applies different DC voltages to the first group of electrodes and the second group of electrodes, so that ions entering the area between the first group of electrodes and the second group of electrodes collide with the cooling gas to be decelerated and confined in the area; When the frequency of the alternating voltage applied by the radio frequency power supply to the fourth group of electrodes is the same as the movement frequency of the ions, the ions in the area are emitted from the slits of the fourth group of electrodes.

8. The working method according to claim 7, characterized in that: In the Fourier transform mass analysis mode, the RF voltage applied to the third and fourth electrodes is 0, the controller adjusts the output voltage of the DC power supply, and the DC power supply applies unequal DC voltages to the first and second electrodes, and the ions are confined in the region and make reciprocating motion in the left and right directions; The charge amplifier detects the image current signal on the third group of electrodes; The processing unit performs Fourier transform on the current signal to obtain spectrum and mass spectrum data.

9. The working method according to claim 8, characterized in that: The ion trap mass analysis mode and the Fourier transform mass analysis mode were performed sequentially.

10. The working method according to claim 7, characterized in that: In the ion analysis mode, the DC voltage applied to the two axially symmetrical electrodes in the first and second electrode groups is the same.

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