WO2021056394A1

WO2021056394A1 - Ion control apparatus

Info

Publication number: WO2021056394A1
Application number: PCT/CN2019/108460
Authority: WO
Inventors: 吴庆浩; 张融
Original assignee: 瑞湾科技（珠海）有限公司
Priority date: 2019-09-27
Filing date: 2019-09-27
Publication date: 2021-04-01
Also published as: CN110809813A

Abstract

Disclosed is an ion control apparatus, wherein same is an apparatus for ion generation, transmission and mass analysis. According to the present invention, ions can be directly generated in an ion trap, and a wire electrode arranged in a space is used to capture and trap the generated ions, and the ions are then directly transmitted to a mass analyzer at a very low loss. An electric field generated by different RF voltages on the wire electrode excites and emits ions with different masses, so as to obtain mass spectra of the ions having different masses. An end electrode blocks interference between wire electrodes of two ion control chambers, so that the sensitivity is further improved. The present invention is small in structure, convenient to move and carry, high in sensitivity and wide in application range.

Description

Ion control device

Technical field

The invention relates to an ion control device. In particular, it relates to a device for storing, transmitting and analyzing ions of different masses.

Background technique

Due to its fast speed, excellent recognition ability, high sensitivity and high resolution, mass spectrometers play an important role in modern analytical chemistry. However, the mass spectrometer is relatively large in size, and its shortcomings such as large weight, high power consumption, and complicated manufacturing and maintenance prevent the mass spectrometer from being more widely used. In the application fields of public safety, environmental protection, biochemical analysis and industrial process monitoring, people need small portable mass spectrometers with good performance. The miniature mass spectrometer is one of the best solutions for these applications, because it has the advantage of being able to be deployed in the field and excellent ability to identify unknown compounds. However, the current miniature mass spectrometry technology still cannot meet the requirements for detection sensitivity in these applications. For example, the current sensitivity of the micro-mass spectrometer to detect explosive compounds is at the ppb level, while the airport security inspection requirements need to reach the ppt level or better. The ion trap is one of the best solutions to realize miniaturization of mass spectrometers because of its compact size, relatively high working pressure, and unique ability to realize multi-stage tandem mass analysis (MSn).

According to the structure, ion traps include three-dimensional ion traps and two-dimensional linear ion traps. The three-dimensional ion trap consists of a pair of ring electrodes and two end cap electrodes with a hyperboloid shape. The three-dimensional ion trap was originally disclosed by Paul and Steinwedel in US Patent No. 2,939,952. A radio frequency voltage RF or a direct current voltage DC is added to the ring electrodes, and the upper and lower end cap electrodes are grounded. Gradually increase the highest value of the RF voltage, and the ions enter the unstable zone and are discharged from the small hole on the end cap. Therefore, when the highest value of the RF voltage gradually increases, ions with a mass-to-charge ratio from small to large are sequentially discharged and recorded to obtain a mass spectrum. In the three-dimensional ion trap, due to the limited space used, the space charge effect is obvious, and the storage capacity of ions is limited, which limits the resolution of the mass spectrometer and the linear range of ion detection, thereby affecting the sample analysis performance.

In order to solve these problems, US Patent No. 6,797,950 proposed a two-dimensional ion trap, also called a linear ion trap, which is very similar to a quadrupole mass spectrometer and consists of two sets of hyperbolic rods and two flat plates at both ends. Alternate RF voltages are applied to a set of diagonal hyperbolic rods, and an AC RF voltage with a phase difference of 180 degrees is applied to another set of diagonal hyperbolic rod electrodes. At the same time, by superimposing another weak alternating voltage with a phase difference of 180° on a set of diagonal hyperbolic rod electrodes, the dipole resonance auxiliary excitation mode can be realized. This mode greatly improves the ion emission efficiency and mass resolution of the ion trap.

In the electric field formed by the linear ion trap, in the direction X of ion excitation or ejection, the bound potential component function V(x)=Ax ² that the ions are subjected to is the quadratic field in this direction, or harmonic potential Trap function, the oscillation frequency of ion movement in this direction has nothing to do with the resonance amplitude.

The ideal secondary electric field is realized by the hyperboloid electrode system, but the precision machining and assembly of the hyperboloid electrode are quite difficult. In addition, in the actual manufacturing process, due to the existence of small holes or slits drawn on the hyperboloid electrode, the electrode cannot generate a perfect secondary field. In addition, the aperture on the hyperbolic rod is not large enough, which will block some of the ions from exiting, limiting the further increase in sensitivity. In order to overcome the shortcomings of the electric field, a variety of ion trap designs have been proposed. The more straightforward method is to modify the boundary structure of the ion trap confinement electrode. These methods make the confinement electrode of the ejection direction relatively protrude at the ion exit. For example, the solution proposed by River Rat in the US Patent No. 6,876,658, and the confinement of the ejection direction The method of extending the distance between electrodes relative to the boundary conditions of the ideal quadrupole field.

In order to overcome the above shortcomings, many efforts have been made to replace the hyperbolic rod electrodes with simplified electrodes and to pursue acceptable detection performance. US Patent 6,838,666 describes a system and method for a linear ion trap mass analyzer. The ion trap is formed by simple rectangular electrodes.

The improvement of the restraining electric field can also be realized by using multiple discrete electrode parts for the original restraining electrodes, and adding restraining voltages of different amplitudes to these electrode parts. For the linear ion trap, in Chinese patent CN1585081, Ding Chuanfan designed a linear ion trap surrounded by a printed circuit board. The structure includes a plurality of discrete and adjustable electrode strip patterns. The electrodes are adjusted by a voltage divider capacitor-resistance network. The bound RF voltage and bound DC voltage between patterns. A similar method, as pointed out in US Patent No. 7,755,040 by Li Gangqiang et al., can also be used to construct an axial secondary field electrostatic ion trap.

Wu Qinghao et al. used stainless steel electrodes to generate secondary fields and obtained better resolution (Anal.Chem.2016,88,7800-7806; J.Am.Soc.Mass Spectrom.(2017)). The conductive wire electrode ion trap has the characteristics of small capacitance, good resolution, easy processing, etc. It is of great value in the miniature ion trap. But there are still many problems. These problems include: 1. The conductive wire electrode electrode cannot be effectively stretched and fixed, which causes the metal wire to bend and affects the electric field. 2. Using a symmetrical field, the ions are emitted from two directions evenly when they are emitted. If only one detector is used, half of the ions will not be detected, thereby reducing the sensitivity. The use of two detectors will increase the cost, and there will be a series of problems such as signal merging. 3. The electrostatic field is used to transfer ions from the ion source of the VUV lamp to the ion trap, and the loss of ions is large, which affects the sensitivity.

Summary of the invention

The technical problem solved by the present invention is to meet the above-mentioned problems and requirements, improve ion detection sensitivity, reduce equipment weight and volume, and reduce operating power.

The technical solution adopted by the present invention is an ion control device, which includes at least two support cylinders, a perforated insulating plate, a lead electrode, a lead stretcher and an ion detector. Both ends of the support cylinder are sealed and matched with a perforated insulating plate to form one The cavity is provided with a set of wire electrodes, the center of the perforated insulating plate is provided with a central hole, and a surrounding hole is arranged around the center hole. The wire passes through the surrounding holes on the two front and rear perforated insulating plates to form wire electrodes. The cavity is communicated through the central hole of the perforated insulating plate, terminal electrodes are arranged between the two perforated insulating plates of two adjacent cavities, and an ion detector is connected to one of the supporting cylinders.

The perforated insulating plate is provided with at least four groups of surrounding holes, the wires pass through the surrounding holes for fixing, the wires fixed to the same group of surrounding holes constitute a wire electrode, and the wires of the same wire electrode are applied with the same electrical signal.

Each wire electrode is formed by the same metal wire reciprocally folded back through the corresponding surrounding holes of the front and rear perforated insulating plates.

The wire is a low-resistance resistance wire.

The perforated insulating plate is provided with a groove adapted to the ring-shaped terminal electrode.

The edge of the terminal electrode extends outward, and the extension area is equal to or exceeds the outer contour of the support cylinder.

The two adjacent perforated insulating plates are connected by bolts.

The opposite electrodes in one of the supporting cylinders are a pair of semicircular electrodes.

The cavity enclosed by the support cylinder can be used as an ion capture chamber, and the support cylinder of the ion capture chamber is provided with a sample inlet pipe, an ionization source and a buffer gas inlet pipe.

The perforated insulating plate is provided with a groove adapted to the support cylinder.

An ionization source is also connected to the support cylinder.

A circular or rectangular through hole is provided on the support cylinder, and the through hole is used for introducing ultraviolet light or extracting ions.

The beneficial effects of the present invention are that the ion transmission efficiency is improved, good resolution can be achieved, at the same time, the distributed capacitance is reduced, the tolerance to mechanical and assembly errors is high, and the weight and volume can be reduced.

The optimization of the electric field is essential for any ion trap design. We have made a lot of efforts to optimize the electric field by changing various geometric parameters. Computer simulation provides an effective method to test the impact of geometric parameter design changes, and can minimize labor and R&D costs. Usually we use the following two methods to predict the performance of the ion trap: 1) Calculate the high-order components of the electric field and compare it with the parameter values of the existing ion trap. However, due to the arbitrariness of the parameters, such as the boundary of the electric field and the degree of polynomial curve fitting, it is not ideal to use this method to optimize the geometry of the ion trap. 2) Use computer simulation to estimate the detection performance of the ion trap (for example, mass resolution, ion emission efficiency, etc.). This method provides a direct method to evaluate the geometric structure of the ion trap, so it can be used as an effective method for optimizing geometric parameters of the ion trap. The disadvantage of this method is the large amount of calculation. However, the tremendous advances in computing technology in recent years have basically overcome this obstacle. In the previous work [International Journal of Mass Spectrometry 393: 52-57. In ], the inventor of the present application demonstrated the use of a single-parameter optimization method to study the problem of misalignment in a dual-plate linear ion trap (LIT), and only one geometric parameter was optimized at a time. However, the geometry of the ion trap electrode should be changed in many ways, in this case, multi-parameter optimization is required.

We use computer simulation to optimize based on resolution and peak height as standards, that is, six parameters are optimized simultaneously in a linear ion trap. Then build a test system based on the optimized geometry, and use the experimental results to evaluate the stability map, resolution and sensitivity of the linear ion trap. In the following, we will discuss the advantages of the geometric structure proposed by the present invention, including improving ion transmission efficiency and achieving good resolution, at the same time, reducing distributed capacitance, high tolerance to mechanical and assembly errors, and reducing Weight, reduce volume.

Description of the drawings

Figure 1 is an embodiment of the wire electrode ion trap of the present invention.

Fig. 2 is a structural diagram of the insulating plate and the lead electrode in Fig. 1.

Figure 3 is a perspective view of a perforated insulating plate of the present invention.

Fig. 4 is another drilling method of the porous insulating plate of the present invention.

Fig. 5 shows the ion emission effect in the symmetrical surrounding hole structure of the present invention.

Fig. 6 shows the effect of ion emission in the asymmetric surrounding hole structure of the present invention.

Fig. 7 is a structural diagram of the wire electrode stretching device of the present invention.

Fig. 8 is another structural diagram of the ion control device of the present invention.

Fig. 9 is another structural diagram of the surrounding holes in the perforated insulating plate of the present invention.

Fig. 10 is a structural view of another ion control device of the present invention.

Fig. 11 is a structural diagram of another wire drawing device of the present invention.

Fig. 12 is a structural view of different embodiments of the wire drawing device of the present invention.

Fig. 13 is a structural diagram of the fourth embodiment of the present invention.

Figure 14 is an exploded view of the terminal electrode assembly relationship.

detailed description

The present invention will be further described in detail below in combination with schematic diagrams and specific implementation cases.

The VUV lamp is an ultraviolet lamp.

Example 1, as shown in Figures 1-7.

In the selected implementation case, as shown in Figure 1, three ion control devices are connected in series, and the entire device includes four perforated insulating plates. Among them, the first perforated insulating plate 101a, the second perforated insulating plate 101b and the supporting cylinder one 103a constitutes a perforated insulating plate, and the third perforated insulating plate 101c, the fourth perforated insulating plate 101d and the support cylinder 103c constitute another similar ion trap chamber. The second perforated insulating plate 101b, the third perforated insulating plate 101c and the second support tube 103b constitute an ion analysis chamber. It also includes a set of lead electrodes 102 surrounded by supporting cylinders, an ultraviolet lamp ionization device, that is, a VUV lamp, an electron gun ionization source 106, a buffer gas inlet pipe 107, a sample inlet pipe 108a and a sample inlet pipe 108c. Both ends of the device are also provided with wire electrode stretching devices 118a.

In operation, the wire electrodes in each ion trapping chamber and ion analysis chamber are composed of multiple parallel wire wires. Different electrical signals are applied to the wire electrodes of the ion trapping chamber and ion analysis chamber to form different ion traps, VUV Lamp one 105a, VUV lamp two 105c or electron gun ionization source 106 generates ions in the corresponding ion trap chamber. The generated ions are trapped in the ion trap chamber, and AC voltage is applied to the lead electrodes. When the voltage on the ring terminal electrode in the central hole of the perforated insulating plate is changed, the trapped ions pass through the central hole and are transferred to the ion analysis chamber between the second perforated insulating plate and the third perforated insulating plate, as shown in Figure 2. Shown in 211.

During the operation of the ion trap, the ionization source composed of VUV lamp 105a and VUV lamp 105c or electron gun ionization source 106 can generate ions in the ion trap chamber. There are three mechanisms for ionization sources to generate ions, electron ionization, photoionization and chemical ionization. The electron gun ionization source 106 includes a thermionic emission filament that generates electrons, and a 70V DC voltage is applied to the filament to accelerate the electrons to 70eV. The collision of these electrons with sample molecules will generate positive ions in the ion trapping chamber. The high-energy photons emitted by the VUV lamp of the photoionization source can directly cause the soft ionization of the sample molecules, and can also generate electrons on the surface of the metal cylinder constituting the ion trap chamber through the photoelectric effect, and can also softly ionize the sample molecules after being accelerated by the electric field . In the first embodiment, the photon energy generated by the VUV lamp 105a may be the same as or different from the photon energy of the VUV lamp 105c. If the energies of photons from the two lamps are different, the compounds with different ionization energies can be distinguished by comparing the difference between the ions produced by the two VUV lamps, and the detection and comparison efficiency of the sample is higher. Chemical ionization uses auxiliary chemical reagent molecules in the ion trap, such as gaseous molecules such as acetone and xylene, to generate electrons and positive ions through photoionization. Because the pressure in the ion trap chamber can reach tens of Pa, there is enough time for ideal The ionic molecules react to generate the corresponding positive and negative ions for the analysis sample. The ionization methods that can be used include tip discharges, such as glow discharge or corona discharge, and hot cathode electron emission sources. In the present invention, the VUV lamp is preferred as the ionization source, and the soft ionization effect is good. At the same time, since the lead electrode is composed of several extremely thin metal wires, its shielding of ultraviolet light can be almost ignored, and the ionization effect on the sample gas is very good.

Once ions are generated in the ion trap cavity, they are captured by an electric field generated by a set of wire electrodes (102) applied with an alternating voltage. The structure of the lead electrode is shown in Figure 2. The trapped ions are cooled after multiple collisions with the buffer gas. After a short period of time, the ions are transferred to the analysis chamber by the pulse voltage applied to the terminal electrode two 218b or the terminal electrode three 218c located on the center hole two 211b or the center hole three 211c. Under the containment of the AC electric field, the loss of ions in the process of transmission and transfer is very small, which significantly improves the detection sensitivity of the system. Since the loss is reduced by an order of magnitude, the demand for samples has been reduced a lot, and the detection can be achieved when the sample volume is too small to be detected, which greatly increases the scope of detectable applications. There is no need to consume a lot of power to generate a large amount of ions like existing equipment, get rid of the huge ion generation and capture device, and the ion transmission is also very efficient. The process of ion generation, capture and transmission is all in an integrated device. Completed in a vacuum environment, the power consumption of the entire device is greatly reduced, the volume is very small, it is very easy to carry to the site for testing, no need to collect and transfer samples, more efficient in time, more flexible in space.

Every time the ion control device runs for a period of time, it must be cleaned to remove the attachments on the electrode, otherwise it will affect the detection accuracy. This requires taking the device out of the vacuum environment, disassembling the device shell, and cleaning the leaking electrode, which delays the running time of the device, and repeated disassembly and assembly also affect the firmness and service life of the device. In order to avoid this work, the wire can be made of a resistance wire with a certain low resistance value, which will generate heat during operation, so that the attachment will fall off automatically, and it will not affect the electric field of the ion trap. Improve use efficiency and device life. When one wire electrode is composed of one wire, the resistance value of each wire electrode is only 0.1-10 ohms.

As shown in Figure 1, each insulating plate is provided with four positioning and

calibration holes

120a, 120b, 120c, and 120d, which can easily determine the positions of the perforated insulating

plates

101a, 101b, 101c, and 101d. When assembling, the position of the perforated insulating plate can be accurately determined and maintained by the rigid rod passing through the calibration hole for position calibration.

As shown in FIG. 1, the buffer gas is introduced into the ion analysis chamber through the buffer gas inlet pipe 107, and the sample gas is introduced into the two ion trap trap chambers from the first sample inlet pipe 108a and the second sample inlet pipe 108c. The separate introduction of these two gases overcomes the problem of pressure imbalance in the original design Anal.Chem. 2016,88,7800-7806; J.Am.Soc.Mass Spectrum. 2017. This method can increase the sample gas flow, thereby improving the sensitivity of the system. The slit 121 on the side wall of the square sleeve of the ion analysis chamber is used to emit ions, and the emitted ions can be detected by the ion detector 109.

One or more groups of VUV lamp ionization devices are respectively installed on both sides of the supporting tube 103a and the supporting tube 103c. The photons emitted by the VUV lamp pass through the window 112 and radiate into the support cylinder to ionize the sample molecules. Multiple sets of VUV lamp ionization devices improve the ionization efficiency, thereby increasing the sensitivity of the system. In the implementation process, VUV lamps of different wavelengths can also be used to obtain distinguishable mass spectra. For example, shorter-wavelength VUV lamps can ionize most organic compounds. The use of a VUV lamp with a slightly longer wavelength can only effectively ionize compounds with lower ionization energy. By comparing the two sets of mass spectra, it is possible to distinguish the differences in the ionization energy of the compounds in the sample gas, thereby obtaining information on the types of compounds.

Fig. 2 shows the structure of the perforated insulating plate and the lead electrode in Fig. 1. The supporting cylinder 103a, the supporting cylinder 103b, and the supporting cylinder 103c are removed in the figure for better display. Four perforated insulating plates, one perforated insulating plate 201a, two perforated insulating plates 201b, three perforated insulating plates 201c and four perforated insulating plates 201d are connected by three sets of front and rear metal wires. The three sets of metal wires respectively constitute the front wire electrode 202a, The lead electrode 202b, the rear lead electrode 202c, and the lead electrodes of each group have the same distribution and can be connected to each other before and after. Among them, the perforated insulating plate is distributed with a central hole and multiple sets of surrounding

holes

212a, 212b, 212c, 212d around the central hole, and each set of surrounding holes is fixed with a metal wire belonging to the same wire electrode. The

central holes

211a, 211b, 211c, and 211d of each perforated insulating plate are fixed with metal rings to form

terminal electrodes

218a, 218b, 218c, 218d. A voltage is applied to the terminal electrodes to control the transmission of ions along the symmetry axis 221. Applying an AC voltage signal to the wire electrode can form an ion trap electric field. The ions are trapped in the trap area formed by wire electrode one 202a, wire electrode two 202b, wire electrode three 202c, terminal electrode two 218b, and terminal electrode three 218c. The wire electrodes before and after the perforated insulating plates in the figure may not be connected to each other. At the same time, the ion trap electric field formed by the wire electrodes in the front and back support cylinder cavities can be different, which can be used for multiple detection and comparison methods. . The connection method of the lead electrodes between the perforated insulating plates is shown in Figure 3. A series of positioning and

calibration holes

220a, 220b, 220c, and 220d are used to confirm the positions of the perforated insulating

plates

201a, 201b, 201c, and 201d.

The support cylinder is inserted into the

grooves

214b, 214c, 214d on the perforated insulating

plates

201a, 201b, 201c, and 201d, one of the grooves is blocked and is not visible in FIG. 2. The width of the groove is slightly larger than the wall thickness of the support cylinder, so that the support cylinder can be tightly fixed, and at the same time it has a sealing effect. Since the entire device is placed in a vacuum environment, the sealing of the support cylinder and the perforated insulating plate is combined with the surrounding holes, center holes, ion exit holes, etc. of very small sizes, which can ensure that there is an order of magnitude between the inside and outside of the ion trap cavity The pressure difference. In order to achieve better resolution, the optimal pressure inside the ion trap is about 0.1 to 0.5 Pa, and the pressure outside the ion trap is about 0.01 Pa. In order to maintain this pressure difference, the sealing design of the present invention can meet this requirement. In addition, better sealing will reduce the consumption of buffer gas and reduce operating costs. The grooves on the perforated insulating plate one 201a and the perforated insulating plate four 201d at both ends of the device are made on one side, and the grooves on the perforated insulating plate two 201b and the perforated insulating plate three 201d in the middle of the device need to be made on both sides .

Figure 3 shows the hole structure on the perforated insulating board, including three types of holes. The first type of hole is the central hole 311, which is located in the central area of the perforated insulating plate and is used to pass ions. A metal ring is installed on the central hole 311, and a voltage is applied to the metal ring to form a terminal electrode. Appropriate DC voltage applied to the metal ring can control ion transmission along the central axis parallel to the wire electrode. The second type of hole is a surrounding hole, a total of 16 holes, the surrounding hole diameter is very small, used to allow the wire electrode to pass through and fix the position of the wire. Considering the simulation of the electromagnetic field and the control of the voltage applied to the wire electrode, the surrounding holes can be grouped, four surrounding holes form a group, the wires passing through the same group of surrounding holes are connected to each other, the same AC voltage is applied, and the voltage amplitude is 10V To 10000V, it becomes a wire electrode. There are four groups of surrounding holes, the first surrounding hole 312a, the second surrounding hole 312b, the third surrounding hole 312c and the fourth surrounding hole 312d, respectively corresponding to the four wire electrodes. The position of the surrounding hole may be symmetrical or asymmetrical with respect to the center position. The third type of holes are the calibration holes 320 used to calibrate the positions of the perforated insulating plates, and the calibration holes are symmetrical with the center of the plate.

The position of the surrounding hole can be determined by calculation by simulation software. On a two-dimensional plane, the position of each hole has two position parameters. For symmetrical structures, the position of the symmetrical hole can be determined by symmetry. In the simulation software, thousands of ion operations are simulated in the device to obtain mass spectra, and the positions of these small holes are optimized according to the resolution and sensitivity of the obtained mass spectra. Based on these standards, the location of these small holes can be completely determined. For example, in a symmetrical implementation case using 16 holes, as shown in Figure 3, the positions of the four holes are (6.7,0.7), (6.8,3), (1.5,7), (4.5,7), The center of the central hole is set to (0,0), and the positions of the remaining surrounding holes are determined according to the principle of center symmetry. For an asymmetric structure, as shown in Figure 4, the positions of all these surrounding holes need to be calculated separately. According to actual needs, the size of the ion trap can be easily scaled. The metal wire wire passes through the surrounding hole to form a wire electrode through multiple turns. The machining accuracy of the surrounding hole is only 0.1mm. However, the machining accuracy of the existing quadruple rod needs to reach the micron level, which is difficult and costly. It is extremely high and cannot be changed after processing and forming. The lead electrode can be flexibly replaced with the perforated insulating plate, and different surrounding hole distributions are used to form different ion traps, which is more industrially practical.

In FIG. 3, the same high-voltage alternating electrical signal AV is applied to the two sets of metal wire wire electrodes, such as the second wire electrode 316b and the fourth wire electrode 316d. On the other opposite two groups, for example, the first wire electrode 316a and the third wire electrode 316c, the high-voltage alternating electrical signal AV with a phase difference of 180° is applied to the wire electrode. This alternating high-voltage electrical signal AV provides a trapping electric field for trapping ions. The amplitude of the high-voltage alternating electrical signal is between 50V and 10000V. In addition, an alternating AV signal with a signal amplitude less than 10V is superimposed on the wire electrode in the hole 316a. At the same time, an electrical signal with the same amplitude that is 180 degrees different from that on the first wire electrode 316a is applied to the third wire electrode 316c. Similarly, such a low-voltage alternating AC signal with a phase difference of 180° can also be superimposed on the second wire electrode 316b and the fourth wire electrode 316d. In addition, in addition to applying a low-voltage AC signal, a constant potential difference of less than 10V needs to be applied to the first wire electrode 316a and the third wire electrode 316c, which can help positive ions and negative ions to exit the ion trap in opposite directions.

Figure 4 shows another hole distribution structure of the perforated insulating plate. In this structure, the central hole 411 is provided in the central area of the perforated insulating plate. There are 18 surrounding holes, divided into 6 groups, 3 in each group, each group of surrounding

holes

412a, 412b, 412c, 412d, 412e, 412f are distributed around the central hole 411. Wherein, the high-voltage alternating voltage signal AV is applied to the wire electrodes passing through the first surrounding hole 412a, the third surrounding hole 412c and the fifth surrounding hole 412e. A high-voltage alternating voltage signal AV having the same amplitude and a phase difference of 180 degrees is applied to the wire electrode passing through the second surrounding hole 412b, the fourth surrounding hole 412d and the sixth surrounding hole 412f. The amplitude of the high-voltage alternating voltage signal AC is between 50V and 10000V. The AV signal thus applied can form a confining electric field for trapping ions in the cavity. The principle of this design is that the electric field formed by six groups of wire wires is similar to the electric field in a hexapole ion transmitter as an ion transmission device. Therefore, based on the same principle, the electric field in the octopole ion transmitter and other multi-electrode ion transmitters can also be constructed in a similar way. The number of lead electrodes is an integer multiple of four or six.

The wire threading method in Figure 3 can adopt the following method. A metal wire is folded three times between two perforated insulating plates to form four parallel wires to become a wire electrode. The two ends of the wire can be At the same time, it is fixed on a wire stretcher, and the surrounding hole only serves as a positioning function. The electric signal is applied to this wire to ensure that the same voltage signal is on each wire on the wire electrode. In Figure 4, each wire electrode is composed of three parallel wires. The wire winding method can be that one wire is folded back twice between two perforated insulating plates. One end of this wire is connected to the wire tensioner, and the other One end is fixed to the perforated insulating board. The surrounding hole also plays a fixed role. Another threading method can also be used. Two wire electrodes that need to apply the same voltage signal are folded back five times by the same wire to form six parallel wires to form two wire electrodes. Pay attention that the wire avoids the end electrodes. The metal wire is very thin, and there is no friction between it and the surrounding hole. The more the same wire is turned back, the advantage is that the consistency of the wire tension is stronger. The disadvantage is that the wire tension will be more sensitive to the tensioner’s response. If the extension bolt moves slightly, the movement of the wire will be magnified more times. You need to be more careful when adjusting the tension, and the extension bolt needs to be more stable.

Figures 5 and 6 show the difference between the symmetrical structure's surrounding hole distribution and the asymmetrical structure's surrounding hole distribution. In the symmetrical surrounding hole structure in Figure 5, most ions are emitted in equal amounts from two opposite sides. In the asymmetric surrounding hole structure of Fig. 6, due to the movement of the surrounding hole positions, the surrounding hole positions become asymmetric with respect to the central axis, so that a unidirectional emission effect of ions can be obtained. This design of asymmetric surrounding holes can generate more parameters to optimize the performance of the ion trap. Because of the asymmetry, two parameters are added to the position of each hole, which can better optimize the performance and reduce an ion detector, which not only reduces the cost, but also improves the detection sensitivity of the mass spectrometer. The reference numeral in FIG. 5 is positioning hole-520, and the reference numeral in FIG. 6 is positioning hole-620.

Figure 7 shows the wire electrode stretching device. The design includes a wire fixing frame 718 and some hollow bolts 719. Wherein, the wire fixing frame 718 is provided with a set of threaded holes 720. The axis of the threaded hole 720 forms an angle of 0° to 90° with respect to the plane of the fixing plate 701. In the case of insufficient space, the use of multiple angles can effectively utilize the space. The hollow bolt is installed in the threaded hole 720. Each lead electrode passes through a through hole at the center of a hollow bolt 719, where the lead electrode is knotted or welded. The tensile force applied to the lead electrode can be determined by adjusting the rotation position of the hollow bolt 719. This design is simple and easy to use, and the pulling force can be adjusted individually for each lead electrode, thereby solving the problem of uneven tension of the lead electrode in the original design.

Implementation case 2, as shown in Figures 8 and 9.

Figure 8 shows the structure of another ion control device. This structure uses three perforated insulating plates, a first perforated insulating plate 801a, a second perforated insulating plate 801b, and a third perforated insulating plate 801c. The plate has positioning and calibration holes 820, and several groups of surrounding holes 812. The lead electrode between the first perforated insulating plate 801a and the second perforated insulating plate 801b forms an ion trap chamber 803, and the lead electrode between the second perforated insulating plate 801b and the third perforated insulating plate 801c forms an ion mass analysis chamber 804. In the ion trap chamber, the surrounding hole distribution pattern of the first insulating plate 801a is similar to the pattern shown in FIG. 4. In this design, the lead electrode in the ion trap chamber and the ion trap mass analysis chamber are independent of each other, and are connected through the second perforated insulating plate 801b shown in FIG. 9. This design utilizes the surrounding hole distribution structure in Figure 4 and has a relatively large ion mass range, thereby increasing the mass range of trapped ions.

Figure 9 shows a configuration of surrounding holes of a perforated insulating plate connecting two ion control devices. The center hole is located in the central area, and the surrounding small holes are composed of two sets of small holes of different sizes and positions. A set of

front surrounding holes

913a, 913b, 913c, 913d, 913e, 913f are used to install the lead electrode of the front ion trap chamber. There are six groups, three in each group; the other set of rear surrounding

holes

912a, 912b, 912c, and 912d are used to install the lead electrodes of the back-end ion analysis chamber, which are divided into four groups, with three in each group. The three metal wires passing through the same group of surrounding holes are a wire electrode, and the same voltage is applied. The voltage applied by adjacent wire electrodes belonging to the same ion control room has a phase difference of 180°. The details are as follows: Two sets of AV signals with a phase difference of 180 degrees but the same amplitude are applied to the wire electrodes passing through the

front surrounding holes

913a, 913c, 913e and the wire electrodes passing through the

front surrounding holes

913b, 913d, 913f, respectively on. Similarly, AV signals having a phase difference of 180 degrees but the same amplitude are applied to the wire electrodes passing through the

rear surrounding holes

912a, 912c and the wire electrodes passing through the surrounding

holes

913b, 913d, respectively. The distribution of these surrounding holes can be symmetrical or asymmetrical with respect to the center of the perforated insulating plate, as shown in Figs. 5 and 6.

Implementation case 3 is shown in Figures 10 and 11.

Figure 10 shows the structure of another ion control device. In the selected implementation case, three ion control devices are connected in series. The first perforated insulating plate 1033a and the second perforated insulating plate 1033b constitute an ion trapping chamber; the second perforated insulating plate 1033b and the third perforated insulating plate 1033c constitute an ion transmission chamber; the third perforated insulating plate 1033c and the fourth perforated insulating plate 1033d constitutes the ion analysis chamber. Two through holes are provided on the side wall of the first support cylinder 1036a to allow the ultraviolet light generated by the

VUV lamps

1040a and 1040b to pass. A through hole 1038 is provided on the side wall of the second support cylinder 1036b to limit the air pressure in the cavity. A cut is provided on the side wall of the third support cylinder 1036c to allow the emitted ions to pass. The tensioner at one end includes a metal wire fixing frame 1041a and a set of fixing bolts 1037a on it. The tensioner at the other end includes a metal wire fixing frame 1041d and a set of fixing bolts 1037d on it.

Figure 11 shows the structure of another wire drawing device. In the selected embodiment, the stretching device includes a wire fixing frame 1140, a wire fixing block 1141, and a tension bolt 1142. The advance and retreat of the tension bolt 1142 adjusts the tension of the wire. Among them, the wire fixing frame made of insulating material is provided with three types of threaded holes: reinforcement holes 1145, wire holes 1146 and holes 1147. The wire hole 1146 is used to pass the metal wires so that they can be fixed by the wire fixing block 1141. The hole 1147 has an internal thread for installing the tension bolt 1142, and the fixing block 1141 is rotated to provide pressure. The reinforcement hole 1145 is used to install a bolt to tighten the tension bolt 1142 to prevent the wire tension bolt 1142 from moving. The wire fixing block 1141 has a through hole 1142 and a threaded hole 1143. The metal wire passes through the through hole 1142 and is fixed by a bolt 1148, and is installed in the threaded hole 1143. The groove 1102 is used to maintain the position of the wire fixing block 1141.

Figure 12 shows another embodiment of the stretching device. The stretching device includes a wire fixing frame 1201, eight wire stretching bolts 1202, eight wire fixing blocks 1203 and eight wire fixing bolts 1204. In the wire fixing frame 1201, eight large threaded holes 1205 are provided on the frame. The wire tension bolt 1202 is installed in the threaded hole 1205 to provide a pulling force to the wire by rotating the tension bolt 1202. The wire fixing block 1203 fixes the wire by the wire fixing bolt 1204 installed. The threaded hole 1206 is used to fix the tension bolt 1202 to prevent movement after the wire is tightened.

The fourth embodiment is shown in Figure 13.

The device includes four perforated insulating

plates

1354, 1352, 1361, and 1360 to form two ion control chambers. Wherein, a terminal electrode 1357 is fixedly installed between the perforated insulating

plates

1352 and 1361. The two perforated insulating plates are fastened together by four bolts 1356, and the terminal electrode 1357 is clamped inside. This can reduce the mutual interference between the electromagnetic fields generated by the lead electrodes of two adjacent ion control chambers. The terminal electrode 1357 has a circular center hole, the edge of the electrode extends outward, and the shape matches the grooves on the perforated insulating

plates

1352 and 1361, and is ready for installation. It is sufficient to ensure that the terminal electrode is not in contact with the lead electrode. The terminal electrode is made of conductive material, and its edge extends outwards to expand the cross-sectional area. Not only can the installation be more stable, but also the electromagnetic field generated by the two lead electrodes can be completely isolated. interference. Preferably, the outer contour of the end electrode can match the outer contour of the support cylinder, or exceed the range of the support cylinder to form an isolation layer closest to the closed state.

In the device, the metal wire electrode in the ion control chamber can also be replaced by semicircular electrodes 1350 and 1353, and the electric field generated is similar to that of the metal wire electrode, which can further reduce the mutual interference of electromagnetic fields. There are grooves on the perforated insulating

plates

1354 and 1352, the shape of which matches the semicircular electrode. The semicircular electrodes are fixed in the grooves of the perforated insulating

plates

1354 and 1352. The wire electrode 1366 passes through the perforated insulating

plates

1352 and 1354 and is tensioned by the wire stretcher 1355. Both the support cylinder 1351 and the semicircular electrode provide support to ensure that the metal wire is straightened.

Figure 14 shows an exploded view of the assembly relationship between the terminal electrode and the perforated insulating plate. For clarity, both the terminal electrode and the perforated insulating plate show cross-sections. The terminal electrode 1403 is sandwiched between the front perforated insulating plate 1401 and the rear perforated insulating plate 1402. A central hole 1423 is provided on the terminal electrode 1403 for passing ions. The perforated insulating plate also has a through hole 1411. In order to match the circular electrode, the through hole may have an irregular shape, and the area of the through hole 1411 is larger than the central hole 1423 of the terminal electrode. The edge of the terminal electrode 1403 extends outward and forms a flanging 1413 facing both sides. The flanging 1413 keeps a certain distance between the terminal electrode 1403 and the two perforated insulating plates without contacting the wire.

Claims

An ion control device, which is characterized in that it comprises at least two support cylinders, a perforated insulating plate, a lead electrode, a lead stretcher and an ion detector. The two ends of the support cylinder are respectively sealed and matched with a perforated insulating plate to form a cavity, A set of lead electrodes is arranged in the cavity, the center of the perforated insulating plate is provided with a central hole, and a surrounding hole is arranged around the central hole. The lead wire passes through the surrounding holes on the two front and rear perforated insulating plates to form a lead electrode, and two adjacent cavities pass through The central holes of the perforated insulating plates are communicated, end electrodes are arranged between the two perforated insulating plates of two adjacent cavities, and an ion detector is connected to one of the support cylinders.
The ion control device according to claim 1, wherein the perforated insulating plate is provided with at least four groups of surrounding holes, the wires pass through the surrounding holes for fixing, and the wires fixed to the same group of surrounding holes constitute a wire electrode , The same electrical signal is applied to the wires of the same wire electrode.
3. The ion control device according to claim 2, wherein each wire electrode is formed by the same metal wire reciprocatingly passing through the corresponding surrounding holes of the two perforated insulating plates at the front and rear.
3. The ion control device of claim 2, wherein the wire is a low-resistance resistance wire.
The ion control device according to claim 1, wherein the perforated insulating plate is provided with a groove adapted to the ring-shaped terminal electrode.
The ion control device according to claim 1, wherein the edge of the terminal electrode extends outward, and the extension area is equal to or exceeds the outer contour of the support cylinder.
5. The ion control device according to claim 1, wherein the two adjacent perforated insulating plates are connected by bolts.
The ion control device according to claim 1, wherein the opposite electrode in one of the supporting cylinders is a pair of semicircular electrodes.
The ion control device according to claim 1, wherein the cavity enclosed by the support cylinder can be used as an ion trap chamber, and the support cylinder of the ion trap chamber is provided with a sample inlet pipe, an ionization source and a buffer gas inlet pipe.
The ion control device according to claim 1, wherein the perforated insulating plate is provided with a groove adapted to the support cylinder.
8. The ion control device according to claim 1, wherein an ionization source is also connected to the support cylinder.
9. The ion control device according to claim 9, wherein a circular or rectangular through hole is provided on the support cylinder, and the through hole is used for introducing ultraviolet light or extracting ions.