WO2021056395A1

WO2021056395A1 - Wire electrode ion control device stretcher and wire tension control method

Info

Publication number: WO2021056395A1
Application number: PCT/CN2019/108463
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: CN110881279A

Abstract

Disclosed are a wire electrode ion control device stretcher and a wire tension control method, which are used for ion generation, transport and mass analysis devices. The present invention can directly generate ions in an ion trap, and use wire electrodes arranged in a space to capture and trap the generated ions, and the ions are directly transported at an extremely low loss to a mass analyzer to obtain mass spectra of different mass ions. By means of the stretcher adjusting the tension of the wire and by means of measuring the sound frequency of the shifted wire so that the tension of the wire is kept consistent, the optimization of forming an ion trap electric field is ensured. Therefore, the present invention has a small and compact structure, has a detection means that is flexible and easy to operate, and is suitable for the fabrication and detection of a wire electron ion trap.

Description

Wire electrode ion control device stretcher and wire tension control method

Technical field

The invention relates to the technical field of ion manipulation and analysis devices. In particular, it relates to the adjustment and measurement device and method of the lead electrode.

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 expulsion, the bound potential component function V(x)=Ax2 that the ion is subjected to in this direction is a quadratic field in this direction, or a harmonic potential trap Function, the oscillation frequency of ion movement in this direction has nothing to do with the resonance amplitude.

The four hyperbolic rod electrodes are arranged in parallel to form an ion trap, and one of the hyperboloid electrodes needs to be opened with a small hole so that the resonant ions are emitted through the small hole. Compared with the three-dimensional ion trap, the trapped ions are significantly increased, which can improve the detection sensitivity. However, such a two-position linear ion trap requires very precise processing machinery to form the required precise hyperbolic rod electrode, and therefore the cost is relatively high. 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 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. A more direct method is to modify the boundary structure of the ion trap confinement electrode. This method makes the confinement electrode in the ion exit direction relatively protrude at the ion exit. For details, please refer to the solution proposed by River Rat in US Patent No. 6087658. In addition, the method of increasing the distance between a pair of ideal quadrupoles is also widely used. By partially replacing the original confined electrodes with multiple discrete electrodes, and simultaneously applying different confining voltages to these discrete replacement electrodes, the local electric field can also be improved. For linear ion traps, in Chinese patent CN1585081, Ding Chuanfan designed a linear ion trap surrounded by a printed circuit board. The structure includes a plurality of discretely adjustable electrode strip patterns. He used the capacitor-resistor network of the voltage divider to adjust the RF voltage and the limited DC voltage between these electrode patterns. Similarly, as pointed out in US Patent No. 7,755,040 of Gangqiang Li et al., an electrostatic ion trap with an axial secondary field can also be constructed. One of the inventors of this patent, Wu Qinghao and others have used stainless steel wire electrodes to generate the secondary field and obtain better resolution (see the Journal of Analytical Chemistry 2016, Volume 88, pages 7800-7806, and the Journal of the American Society for Mass Spectrometry 2017 issue ).

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 provide a wire electrode ion control device stretcher and a wire tension control method to improve ion detection sensitivity, which can greatly improve the consistency of the tension force of each wire in the wire electrode, and make the wire electrode formed The electric field of the ion trap is more perfect.

The technical solution adopted by the present invention is a wire electrode ion control device stretcher, which includes at least two supporting cylinders, a perforated insulating plate, a wire electrode, a wire stretcher, and an ion detector. The perforated insulating plate is sealed and matched 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 the central hole is provided with a metal ring. A support tube and a support tube are arranged between two adjacent perforated insulating plates. A set of wire electrodes, the number of each set of wire electrodes is at least 4, each wire electrode includes at least 2 wires parallel to each other, the perforated insulating plate is provided with surrounding holes, and the two ends of the wires are respectively passed through and fixed to the front and back Surrounding holes on a perforated insulating board;

The perforated insulating plate is connected with a tensioner that adjusts the tension of the wire. The tensioner includes a tension bolt and a fixing bolt. The tension bolt connects the wire. As the tension bolt is screwed, the tension of the wire changes. After the tightening force is adjusted, clamp the tension bolt with the fixing bolt, and tighten the position of the tension bolt.

The tension bolt is a hollow bolt, and the wire passes through the through hole in the hollow bolt and is fixed on the tension bolt.

The axis of the fixed bolt is perpendicular to the axis of the tension bolt, and the fixed bolt supports the side of the tension bolt to fix the tension bolt.

The tensioner also includes a wire fixing frame, the wire fixing frame and the perforated insulating plate are fixedly connected, the wire fixing frame is provided with threaded holes, and the threaded holes are equipped with tensile bolts.

The stretcher also includes a fixing block and a bolt on the fixing block, the wire is clamped to the fixing block by the bolt, and the fixing block is sleeved on the tensile bolt.

The wire fixing frame is a round or square frame, and the frame is provided with a through hole connecting the inside and the outside, and the wire passes through the through hole.

A groove is arranged in the wire fixing frame, and the fixing block is located in the groove.

Each wire electrode is formed by the same metal wire passing through the corresponding surrounding hole back and forth, and the wire tension of each wire electrode is adjusted by a tension bolt.

The device includes at least three perforated insulating plates. The center of the perforated insulating plate is provided with a central hole, and a metal ring is arranged on the central hole. A support tube and a set of wire electrodes are arranged between two adjacent perforated insulating plates. The number of electrodes is at least 4, each wire electrode includes at least 3 wires parallel to each other, the perforated insulating plate is provided with surrounding holes, and both ends of the wires are respectively passed through and fixed to the surrounding holes on the front and rear perforated insulating plates On the upper side, the support cylinder encloses the lead electrode and seals and cooperates with the two front and rear perforated insulating plates to form a cavity; the perforated insulating plate is connected with a tensioner for adjusting the tension of the wire, the tensioner includes a tension bolt and a fixing bolt , The tension bolt is connected to the wire. With the tightening of the tension bolt, the tension of the wire changes. After the tension is adjusted, the tension bolt is clamped with the fixed bolt to tighten the position of the tension bolt;

Tighten the tension bolt, apply tension to the guide wire, pull each wire, measure and record the sound frequency of each wire with a sound frequency tester, take the frequency value as the reference value, and the upper and lower 500Hz of the reference value is qualified Range, adjust the corresponding tensile bolts of the corresponding wires, loosen the wires whose pronunciation frequency is higher than the qualified range, continuously measure their pronunciation frequency until their pronunciation falls into the qualified range, tighten the wires whose pronunciation frequency is lower than the qualified range, and continuously measure their pronunciation Frequency until its pronunciation falls into the qualified range.

The optimization of the electric field is essential for the design of any ion trap. It is necessary 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 ion traps: 1) Calculate the higher-order components of the electric field and compare them with the parameter values of existing ion traps. 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.

The beneficial effect of the present invention is that the ion transmission efficiency can be improved through the ion control chambers connected in series, and good resolution can be achieved. At the same time, the distributed capacitance can be reduced, the tolerance to mechanical and assembly errors can be high, and the weight can be reduced. Small size. The stretching operation of the wire is easy, and the stretching force can be basically kept the same. The uniformity of the tensioning force of each wire enables the actual electromagnetic field to fully realize the simulated electromagnetic field state.

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 stretcher 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 metal wire wire tensioner of the present invention.

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

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 stretchers 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 an alternating voltage is applied to the lead electrode. When the voltage on the ring 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. 211 shown.

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 current signal. 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 center electrode two 218b or the center electrode three 218c located on the center hole two 211b or the center hole three 211c, as shown in FIG. 2. 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.

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 metal rings 218a, 218b, 218c, and 218d at the center of each perforated insulating plate are tightly fixed in the

central holes

211a, 211b, 211c, and 211d of each perforated insulating plate to control the transmission of ions along the axis of symmetry 221. Applying an AC voltage signal to the wire electrode can form an ion trap electric field. The ions are trapped in a trapped area formed by wire electrode one 202a, wire electrode two 202b, wire electrode three 202c, central metal ring two 218b, and central metal ring 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. The wires belonging to the same wire electrode are formed by the same metal wire reciprocating and passing through the corresponding surrounding holes, which can simplify the wire fixing method and facilitate the application of voltage signals. 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 .

There are three types of holes on the perforated insulation board. As shown in Figure 3. The first type of hole is a central hole 311, and a metal ring is installed on the central hole 311. 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 holes are surrounding holes for the wire electrode to pass through. Four such holes form a group, a total of four groups of surrounding holes, the first surrounding hole 312a, the second surrounding hole 312b, and the third surrounding hole 312c And the fourth surrounding hole 312d. The wires passing through the same group of surrounding holes are connected to each other, and the same voltage signal is applied to become a wire electrode. 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 wire electrode is formed through the surrounding hole, and 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 to process, and the processing cost is extremely high. It cannot be changed after forming, and 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.

Definition: AV signal refers to a high-voltage alternating electrical signal with an amplitude between 50V and 10000V. AC signal refers to a low-voltage alternating signal with an amplitude of 0-10V and a frequency of about one-third of the AV amplitude. And can be adjusted.

In FIG. 3, the same high-voltage alternating electrical signal AV is applied to the two sets of metal wire wire electrodes, for example, 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 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, there is a central hole 411 in the central area of the perforated plate. 6 groups of surrounding holes, 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 stretcher. 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.

Because the wire is very thin, the tension change is very sensitive, and the consistency of the wire tension is very important to the ion trap electric field. The tension adjustment method of the present invention is as follows: twist the tension bolt, apply tension to the wire, Toggle each wire, use a sound frequency tester to measure and record the frequency of the sound emitted by each wire. The first choice is to set a reference value. The reference value can be selected as a reference value according to the measured frequency of each wire. A reference value can be set in consideration of the length of the wire and factors. The upper and lower 500Hz of the reference value is the qualified range. Adjust the corresponding tensile bolts of the corresponding wire, relax the wire whose pronunciation frequency is higher than the qualified range, and continuously measure its pronunciation frequency until its pronunciation frequency If it falls into the qualified range, tighten the wire whose pronunciation frequency is lower than the qualified range, and continuously measure its pronunciation frequency until its pronunciation falls into the qualified range.

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.

The ion control chambers of the first perforated insulating plate 801 and the second perforated insulating plate 801b can also be used as ion molecule reaction chambers. Ions are introduced from external equipment and react in the ion molecule reaction chamber.

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. The way of threading the metal wire in FIG. 9 can refer to the description of FIG. 3 and FIG. 4. In this embodiment, there are two wire tensioners, which are installed on the first perforated insulating plate 801a and the third perforated insulating plate 801c, respectively, to adjust the wire electrode tension of the ion trap chamber 803 and the ion mass analysis chamber 804, respectively. Tightness. The detection and adjustment of the tension force of the lead electrode are the same as the adjustment method in the first embodiment.

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 constitute Ion analysis room. 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, which are used to adjust the tension of the wire electrode in the ion transmission chamber. The tensioner at the other end includes a metal wire fixing frame 1041d and a set of fixing bolts 1037d on it, which are used to adjust the tension of the wire electrode in the ion analysis chamber.

Figure 11 shows the structure of another wire tensioner. In the selected embodiment, the tensioner 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. Although the thread has a certain degree of self-locking, the variable range of the tension force of the wire is very small. If one of the tension bolts moves slightly, it may cause a huge difference in the tension force of the wire electrode and affect the tension force of the wire electrode The reinforcement hole 1145 is used to install bolts 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. The wire is connected to the wire fixing block, so in the process of stretching, the tightening of the tension bolt can only affect the tension of the wire, and the wire itself will not be twisted, and the wire will be more straight and stretched. Conducive to the formation of a more ideal ion trap electromagnetic field.

The wire tensioner of the lead electrode in the ion transmission chamber can be installed on the second perforated insulating plate 1033b or the third perforated insulating plate 1033c to adjust the tension force of the lead electrode of the ion transmission chamber. The wire stretcher of the transmission room cannot adopt the same structure as the stretchers at both ends, so a simplified structure can also be adopted. A number of hollow bolts are installed on the perforated insulating plate. The hollow bolts drive the wire electrode of the wire electrode to be stretched. The bolt corresponds to one or two wire electrodes.

Figure 12 shows another embodiment of the stretcher. The tensioner includes a wire fixing frame 1201, eight wire tension 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 tensioner of this structure does not require high requirements for the size of the fixed frame, and the adjustment of the tension bolt is easier to operate.

The wire electrode in each chamber must be tested and adjusted for tension force, and the operation method refers to the adjustment method in the first embodiment.

Claims

A stretcher for a lead electrode 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, and both ends of the support cylinder are sealed with a perforated insulating plate respectively Cooperate to form a cavity with a set of lead electrodes, the center of the perforated insulating plate is provided with a center hole, the perforated insulating plate is equipped with a terminal electrode, and the center of the terminal electrode is provided with a through hole. The through hole and the center hole are in the same position. A support tube and a set of lead electrodes are arranged between two adjacent perforated insulating plates. The number of lead electrodes in each group is at least 4, and each lead electrode includes at least two parallel leads. The perforated insulating plates are provided with surrounding holes. , The two ends of the wire are respectively passed through and fixed on the surrounding holes on the two front and rear perforated insulating plates;

The perforated insulating plate is connected with a tensioner that adjusts the tension of the wire. The tensioner includes a tension bolt and a fixing bolt. The tension bolt connects the wire. As the tension bolt is screwed, the tension of the wire changes. After the tightening force is adjusted, clamp the tension bolt with the fixing bolt, and tighten the position of the tension bolt.
The wire electrode ion control device tensioner according to claim 1, wherein the tension bolt is a hollow bolt, and the wire passes through the through hole in the hollow bolt and is fixed on the tension bolt.
The wire electrode ion control device stretcher according to claim 2, wherein the axis of the fixing bolt is perpendicular to the axis of the stretching bolt, and the fixing bolt supports the side of the stretching bolt to fix the stretching bolt.
The wire electrode ion control device stretcher according to any one of claims 1-3, characterized in that: the stretcher further comprises a wire fixing frame, the wire fixing frame and the perforated insulating plate are fixedly connected, and the wire fixing frame is provided with There are threaded holes, and tension bolts are installed in the threaded holes.
The wire electrode ion control device stretcher according to claim 4, characterized in that: the stretcher further comprises a fixing block and a bolt on the fixing block, the wire is clamped to the fixing block by the bolt, and the fixing block is sleeved on the stretching bolt on.
The wire electrode ion control device stretcher according to claim 4, wherein the wire fixing frame is a round or square frame, and the frame is provided with a through hole connecting the inside and the outside, and the wire passes through the through hole.
The wire electrode ion control device stretcher according to claim 5, wherein a groove is provided in the wire fixing frame, and the fixing block is located in the groove.
The wire electrode ion control device stretcher according to claim 1, characterized in that: each wire electrode is formed by the same metal wire passing through the corresponding surrounding hole back and forth, and the wire tension of each wire electrode is formed by a pulling force. Extend the bolts for adjustment.
A tension control method for a wire stretcher controlled by a wire electrode ion is characterized in that the device includes at least three perforated insulating plates, the center of the perforated insulating plate is provided with a central hole, and the central hole is provided with a metal ring, and two adjacent A support tube and a set of wire electrodes are arranged between the perforated insulating plates. The number of wire electrodes in each group is at least 4, and each wire electrode includes at least 3 wires parallel to each other. The perforated insulating plates are provided with surrounding holes. The two ends of the cable pass through and are fixed on the surrounding holes of the two front and rear perforated insulating plates. The support cylinder encloses the wire electrode and seals and cooperates with the front and rear two perforated insulating plates to form a cavity; the perforated insulating plate is connected with adjustment The tensioner of the wire tension force, the tensioner includes a tension bolt and a fixing bolt, the tension bolt is connected to the wire, as the tension bolt is screwed, the wire tension changes, and the tension is adjusted after the tension is adjusted. The bolt clamps the tension bolt and tightens the position of the tension bolt;

Tighten the tension bolts, apply tension to the guide wires, move each wire, measure and record the sound frequency of each wire with a sound frequency tester, adjust the tension bolts corresponding to the corresponding wires, and relax the pronunciation frequency. For the high wire, tighten the wire whose sound frequency is lower than the qualified range, and continuously measure the sound frequency until the sound falls within the qualified range, and then tighten the corresponding tension bolts with fixing bolts.