CN111033685A - Ion control and mass analysis device - Google Patents

Abstract

The invention discloses an ion control and mass analysis device, which is a device for ion generation, transmission and mass analysis. The invention can directly generate ions in the ion trap, and trap the generated ions by utilizing the wire electrodes arranged in space, and directly transmit the ions to the mass analyzer with extremely low loss. Ions with different masses are excited and emitted out through electric fields generated by different voltages on the lead electrodes, so that mass spectra of the ions with different masses are obtained. The invention has the advantages of small structure, convenient movement and carrying, high detection efficiency, high sensitivity, small number of required samples and wide application range.

Description

Ion control and mass analysis device

Technical Field

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

Background

Due to its rapidity, excellent discriminatory power, high sensitivity and high resolution, mass spectrometers play an important role in modern analytical chemistry. However, mass spectrometers are relatively bulky, and their weight, power consumption, and manufacturing and maintenance complexity have prevented their widespread use. In the application fields of public safety, environmental protection, biochemical analysis, industrial process monitoring and the like, small-sized portable mass spectrometers with good performance are required. A miniature mass spectrometer is one of the best solutions to meet these applications because of its advantages of being able to be deployed in the field and its excellent ability to identify unknown compounds. However, current micro mass spectrometry techniques do not meet the detection sensitivity requirements for these applications. For example, the sensitivity of detecting explosive compounds with miniature mass spectrometers is currently in the ppb level, whereas airport security inspection requirements are required to reach ppt levels or better. Ion traps are one of the best solutions to achieve miniaturized mass spectrometers because of their compact size, relatively high operating pressures, and unique capabilities to achieve multi-stage serial mass analysis (MSn).

Structurally, the ion trap includes a three-dimensional ion trap and a two-dimensional linear ion trap. The three-dimensional ion trap consists of a pair of ring electrodes (ring electrodes) and two end cap electrodes (end cap electrodes) in a hyperbolic shape. Three-dimensional ion traps were originally disclosed by Paul and Steinwedel in U.S. patent No. 2,939,952. Radio frequency voltage RF or direct current voltage DC is added to the annular electrode, and the upper end cover electrode and the lower end cover electrode are grounded. The highest value of the radio frequency voltage is gradually increased, and ions enter an unstable area and are discharged from a small hole in the end cover electrode. Therefore, when the highest value of the radio frequency voltage gradually increases, ions with the mass-to-charge ratio from small to large are ejected to the ion detector and recorded to obtain a mass spectrum. In the three-dimensional ion trap, due to the fact that the used space is limited, the space charge effect is obvious, the storage capacity of ions is limited, the resolution of a mass spectrometer and the linear range of ion detection are limited, and therefore the analysis performance of a sample is affected.

To address these problems, U.S. patent No.6,797,950 proposes a two-dimensional ion trap, also known as a linear ion trap, which is very similar to a quadrupole mass spectrometer, consisting of two sets of doubly curved rods and two plates at both ends. Alternating RF voltages are applied to one set of diagonal, doubly curved rods, and alternating RF voltages with a phase difference of 180 degrees are applied to the other set of diagonal, doubly curved rod electrodes. Meanwhile, another weak alternating voltage with 180-degree phase difference is superposed on a group of diagonal double-crank electrodes, so that a dipole resonance auxiliary excitation mode can be realized. The mode greatly improves the ion extraction efficiency and the mass resolution of the ion trap.

In the electric field formed by the linear ion trap, in the ion excitation or expulsion direction X, the function v (X) of the direction bound potential component of the ion, which is the secondary field or simple harmonic potential well function in the direction, is Ax2, and the oscillation frequency of the ion movement in the direction is independent of the common amplitude.

The ideal secondary electric field is realized by a hyperboloid electrode system, but the precision processing and assembly of the hyperboloid electrode are quite difficult. In addition, in the actual manufacturing process, the electrodes cannot generate perfect secondary fields due to the existence of small extraction holes or slits on the hyperboloid electrodes. In addition, the aperture on the double-curved rod is not large enough, so that the emergence of a part of ions can be blocked, and the further increase of the sensitivity is limited. To overcome the drawbacks of electric fields, various ion trap designs have been proposed. More straightforward methods are to modify the boundary structure of the ion trap's confining electrodes such that the expulsion direction confining electrodes protrude relatively at the ion exit, such as the approach proposed by River Rat in us 6087658, and to stretch the expulsion direction confining electrode spacing outward from its ideal quadrupole field boundary conditions.

To overcome the above-mentioned disadvantages, many efforts have been made to replace the double bent 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 analyser, the ion trap being formed from simple rectangular electrodes.

The improvement of the bound electric field can also be realized by using a plurality of discrete electrode parts for the original bound electrode and adding the bound voltage with different amplitudes on the electrode parts. For linear ion trap, in chinese patent CN1585081, the structure of the linear ion trap enclosed by a printed circuit board includes a plurality of discrete adjustable electrode stripe patterns, and a voltage-dividing capacitor-resistor network is used to adjust the bound radio frequency voltage and bound dc voltage between these electrode patterns. In a similar manner, as indicated in US7755040 to lischk et al, axial secondary field electrostatic ion traps may also be constructed.

Wuqinghao et al generated a secondary field using a stainless steel electrode and achieved better resolution (anal. chem.2016,88, 7800-7806; j.am. soc. mass spectra. (2017)). The conductive wire electrode ion trap has the characteristics of small capacitance, good resolution, easy processing and the like, and has important value in a miniature ion trap. Many problems still remain. These problems include: 1. the conductive wire electrode cannot be effectively stretched and fixed, so that the metal wire is bent to influence an electric field. 2. The use of a symmetric field allows ions to be emitted evenly from two directions when they are emitted, and if only one detector is used, half of the ions cannot be detected, thereby reducing sensitivity. The use of two detectors causes cost increase and has a series of problems such as signal combination. 3. Ions are transported from the VUV lamp ion source to the ion trap using an electrostatic field, and the loss of ions is large, affecting sensitivity.

Disclosure of Invention

The technical problem underlying the present invention is that of solving the above mentioned problems and needs, improving ion detection sensitivity, reducing equipment weight and volume, reducing operating power.

The technical scheme adopted by the invention is that the ion control and quality analysis device comprises at least two supporting cylinders, perforated insulating plates, wire electrodes, a wire stretching device and an ion detector, wherein two ends of each supporting cylinder are respectively matched with one perforated insulating plate in a sealing manner to form a cavity, the wire electrodes are arranged in the cavity, the center of each perforated insulating plate is provided with a center hole, the perforated insulating plates are provided with end electrodes, the centers of the end electrodes are provided with through holes, the positions of the through holes and the center holes are consistent, two ends of each wire electrode are respectively arranged on the front perforated insulating plate and the rear perforated insulating plate, and one of the supporting cylinders is connected with the ion. The central hole is positioned in the central area of the perforated insulating plate and is used for enabling ions to pass through, the through hole on the end electrode is consistent with the central hole in position or axis, and also is used for enabling the ions to pass through, the end electrode can be a metal ring fixed in the central hole, and voltage is applied to the metal ring so as to control the ions to move along the direction of the central symmetry axis. The terminal electrode may also be a conductive end plate having a through hole coaxial with the central hole. The surrounding hole has a very small aperture and is used for passing and fixing a lead electrode for applying an alternating voltage.

At least four groups of surrounding holes are arranged on the perforated insulating plate, the leads pass through the surrounding holes to be fixed, and the leads fixed in the same group of surrounding holes form a lead electrode.

Each cavity is provided with four or more conductive line electrodes, each conductive line electrode is composed of at least three parallel conductive lines, and the conductive lines of the same conductive line electrode are applied with the same electric signal. The electric signals comprise direct current voltage, pulse voltage, radio frequency voltage and different alternating current voltages applied to the wire electrodes, and are used for forming an ion trap electric field required by work.

The cavity surrounded by the supporting cylinder can be used as an ion capturing chamber, and a sample air inlet pipe, an ionization source and a buffer gas inlet pipe are arranged on the supporting cylinder of the ion capturing chamber.

Each wire electrode is formed by the corresponding surrounding hole of the same metal wire which is turned back and forth to penetrate through the front perforated insulating plate and the rear perforated insulating plate.

The wires between two adjacent cavities are communicated with each other or isolated from each other. The mutual connection ensures that the voltage control conditions of all the cavities are consistent, and the mutual isolation can ensure that the voltage control conditions of all the cavities are inconsistent and the ion trap conditions are different.

The distribution of the lead electrodes of two adjacent cavities is kept consistent or different respectively. Under the condition that the wire electrodes between the adjacent cavities are isolated from each other, the wire electrodes can adopt different distribution conditions according to requirements.

The perforated insulating plate is provided with a groove matched with the supporting cylinder. The groove is used for fixing the perforated insulating plate and can enhance the sealing effect.

The ionization source is an ultraviolet lamp, a point discharge, or a hot cathode electron emission source. Other sources may be used where space permits.

The supporting cylinder is provided with a circular or rectangular through hole, and the through hole is used for introducing ultraviolet light or leading out ions.

The invention has the advantages of improving ion transmission efficiency, achieving good resolution, reducing distributed capacitance, having high tolerance to mechanical and assembly errors, reducing weight and reducing volume.

Optimization of the electric field is essential to the design of any ion trap and we have made a great deal of effort to optimize the electric field by varying various geometric parameters. Computer simulation provides an efficient way to test the impact of geometric design changes and minimizes labor and development costs. Generally we predict the performance of an ion trap using two methods: 1) the higher order components of the electric field are calculated and compared to the parameter values of the existing ion trap. However, optimizing the geometry of the ion trap in this way is not ideal due to the arbitrary nature of the parameters, such as the boundaries of the electric field and the degree of polynomial curve fitting. 2) Computer simulations were used to estimate the detection performance (e.g., mass resolution, ion extraction efficiency, etc.) of the ion trap. The method provides a direct method of assessing the performance of the ion trap geometry and therefore it can be an effective method of optimizing the geometry parameters of the ion trap. This method has the disadvantage of being computationally expensive. However, the great advances in computing technology in recent years have made this obstacle essentially overcome. In the previous work [ International Journal of MassSpectrometry 393: 52-57. The inventors of the present application have demonstrated that the problem of misalignment in a dual-plate Linear Ion Trap (LIT) is investigated using a single parameter optimization method, optimizing only one geometric parameter at a time. However, the geometry of the ion trap electrodes should be varied in a number of ways, in which case multi-parameter optimization is required.

We optimized in computer simulations based on resolution and peak height as criteria, i.e. six parameters were optimized simultaneously in a linear ion trap. And then constructing a test system according to the optimized geometric structure, and evaluating the stability graph, the resolution and the sensitivity of the linear ion trap through experimental results. In the following we will discuss the advantages of the proposed geometry of the invention, including the improvement of ion transport efficiency and the possibility of achieving good resolution, at the same time as a reduction of distributed capacitance, high tolerance to mechanical and assembly errors, reduction of weight and volume.

Drawings

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

Fig. 2 is a structural view of the insulating plate and the lead electrode of fig. 1.

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

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

Fig. 5 illustrates the ion extraction effect in the symmetric surrounding aperture structure of the present invention.

Fig. 6 illustrates the ion extraction effect in an asymmetric surrounding aperture structure according to the present invention.

Fig. 7 is a structural view of the lead electrode stretching device of the present invention.

FIG. 8 is another structural view of an ion control device according to the present invention.

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

FIG. 10 is a structural view of another ion control device according to the present invention.

Fig. 11 is a structural view of another wire drawing device according to the present invention.

Fig. 12 is a view of the construction of a different embodiment of the wire guide tensioning device of the present invention.

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

Detailed Description

The present invention will be described in further detail with reference to the drawings and specific embodiments.

The VUV lamp is an ultraviolet lamp.

Example 1, as shown in FIGS. 1-7.

In selected embodiments, as shown in fig. 1, three ion control devices are connected in series, the overall device comprising four perforated insulator plates, wherein the first perforated insulator plate 101a, the second perforated insulator plate 101b and the support cylinder one 103a constitute a perforated insulator plate, and the third perforated insulator plate 101c, the fourth perforated insulator plate 101d and the support cylinder three 103c constitute another similar ion trapping chamber. The second perforated insulating plate 101b, the third perforated insulating plate 101c and the second support cylinder 103b constitute an ion analysis chamber. Also included are a set of wire electrodes 102 surrounded by respective support cylinders, an ultraviolet lamp photoionization device, i.e., a VUV lamp, an electron gun ionization source 106, a buffer gas inlet pipe 107, a sample inlet pipe one 108a, and a sample inlet pipe two 108 c. The two ends of the device are also respectively provided with a lead electrode stretching device 118 a.

In operation, the wire electrodes in each of the ion trapping chamber and the ion analysis chamber are formed by a plurality of wire wires that are parallel to each other, different electrical signals are applied to the wire electrodes of the ion trapping chamber and the ion analysis chamber to form different ion traps, and the VUV lamp one 105a, the VUV lamp two 105c, or the electron gun ionization source 106 generates ions in the corresponding ion trapping chamber. The generated ions are trapped in an ion trap chamber and an alternating voltage is applied to a wire electrode. When the voltage on the ring-shaped end electrode in the central aperture of the perforated insulating plate is changed, the trapped ions pass through the central aperture and are transferred to the ion analysis cell between the second perforated insulating plate and the third perforated insulating plate, as shown at 211 in fig. 2.

During operation of the ion trap, an ionization source consisting of either the VUV lamp one 105a and the VUV lamp two 105c or the electron gun ionization source 106 is capable of generating ions in the ion trap chamber. The ionization source generates ions by three mechanisms, electron ionization, photo ionization 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 70 eV. The collisions of these electrons with the sample molecules will create positive ions in the ion capture chamber. The photoionization source can directly cause the soft ionization of sample molecules by high-energy photons emitted by a VUV lamp, can also generate electrons on the surface of a metal round supporting cylinder forming an ion trap chamber through a photoelectric effect, and can also carry out the soft ionization of the sample molecules after being accelerated by an electric field. In one embodiment, the photon energy generated by the first VUV lamp 105a may be the same as or different from the photon energy of the second VUV lamp 105 c. If the photon energies from the two lamps are different, compounds with different ionization energies can be distinguished by comparing the difference between the ions generated by the two VUV lamps, with greater efficiency in detecting and comparing samples. Chemical ionization generates electrons and positive ions through photo ionization by means of auxiliary chemical reagent molecules in the ion trap, such as gaseous molecules of acetone, xylene and the like, and because the air pressure in the ion trap chamber can reach dozens of pascals, ideal ion molecular reactions can be generated for enough time, so that corresponding positive ions and negative ions of an analysis sample are generated. Ionization methods that can be used are also point discharges, such as glow discharges or corona discharges, and hot cathode electron emission sources. The invention selects the VUV lamp as the ionization source preferably, the soft ionization effect is good, and meanwhile, because the lead electrode is composed of a plurality of extremely fine metal wires, the shielding of ultraviolet light can be almost ignored, and the ionization effect on the sample gas is very good.

Once ions are generated within the ion trap chamber, they are trapped by an electric field generated by a set of wire electrodes (102) to which an ac voltage is applied. The structure of the lead electrode is shown in fig. 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 application of a pulsed voltage at either end electrode two 218b or end electrode three 218c located at center hole two 211b or center hole three 211 c. Under the restraint of an alternating current electric field, the loss amount of ions in the transmission and transfer process is very small, and the detection sensitivity of the system is obviously improved. Because the loss is reduced by one order of magnitude, the demand for the sample is greatly reduced, the detection can be realized only by the situation that the sample amount is too small and cannot be detected, and the detectable application range is greatly improved. Need not to consume very big power in order to produce a large amount of ions like current equipment, got rid of the huge ion of size and produced and trapping apparatus, ion transmission is also very high-efficient, and the process that ion produced, was caught and is transmitted is all accomplished in the device of integration, in the vacuum environment, and whole device consumption greatly reduced is very small and exquisite on the volume, and very convenient to carry takes the field test to, need not to gather and transport the sample, and is more high-efficient on the time, and is more nimble on the space.

As shown in fig. 1, 4 alignment holes 120a, 120b, 120c, and 120d are provided on each insulating plate, and the positions of the perforated insulating plates 101a, 101b, 101c, and 101d can be easily determined. During assembly, the position of the perforated insulating plate can be precisely determined and maintained by performing position calibration through the rigid rods passing through the calibration holes.

As shown in fig. 1, buffer gas is introduced into the ion analysis chamber through a buffer gas inlet pipe 107, and sample gas is introduced into the two ion trap trapping chambers from a sample inlet pipe one 108a and a sample inlet pipe two 108c, respectively. The separate introduction of these two gases overcomes the problem of pressure imbalance in the original design, anal. 2016,88, 7800-7806; mass Spectrum, j.am.soc.mass Spectrum. 2017. This method can increase the sample gas flow rate, thereby improving the sensitivity of the system. The slits 121 in the side wall of the square sleeve of the ion analysis chamber are used to emit ions which can be detected by the ion detector 109.

One or more groups of VUV lamp ionization devices are respectively arranged on two sides of the first supporting cylinder 103a and the third supporting cylinder 103 c. Photons emitted by the VUV lamp radiate through the aperture 112 into the support cartridge, ionizing the sample molecules. The ionization device of the multiple groups of VUV lamps improves the ionization efficiency, thereby improving the sensitivity of the system. In practice, VUV lamps of different wavelengths can also be used to obtain a distinguishable mass spectrum. For example, shorter wavelength VUV lamps are capable of ionizing most organic compounds. Whereas the use of a slightly longer wavelength VUV lamp is only effective in ionizing compounds having a lower ionization energy. By comparing the two sets of mass spectra, the ionization energy difference of the compounds in the sample gas can be distinguished, and thus the type information of the compounds can be obtained.

Fig. 2 shows the structure of the perforated insulating plate and the wire electrode of fig. 1 with the first support cylinder 103a, the second support cylinder 103b and the third support cylinder 103c removed for better illustration. The four perforated insulating plates are a first perforated insulating plate 201a, a second perforated insulating plate 201b, a third perforated insulating plate 201c and a fourth perforated insulating plate 201d which are connected through a front group of metal wires and a rear group of metal wires, the three groups of metal wires respectively form a front lead electrode 202a, a middle lead electrode 202b and a rear lead electrode 202c, the distribution conditions of the lead electrodes of the groups are the same, and the front and the rear can be communicated with each other. The perforated insulating plate is distributed with a central hole and a plurality of groups of surrounding holes 212a, 212b, 212c and 212d around the central hole, and each group of surrounding holes is fixed with metal leads belonging to the same lead electrode. A metal ring is fixed to the center hole 211a, 211b, 211c, and 211d of each perforated insulating plate to form a terminal electrode 218a, 218b, 218c, and 218d to which a voltage is applied for controlling the transmission of ions along the axis of symmetry 221. Applying an ac voltage signal to the wire electrode creates an ion trap electric field. Ions are trapped in the trapping region formed by the first lead electrode 202a, the second lead electrode 202b, the third lead electrode 202c, the second terminal electrode 218b, and the third terminal electrode 218 c. The wire electrodes in the front and the back of each perforated insulating plate in the figure can not be connected with each other, and at the same time, the ion trap electric fields formed by the wire electrodes in the cavities of the front and the back supporting cylinders can be different, so that the ion trap electric field can be used for various detection and contrast modes. The method of connecting the wire electrodes between the perforated insulating plates is shown in fig. 3. A series of alignment holes 220a, 220b, 220c, 220d are used to confirm the position of the perforated insulating plates 201a, 201b, 201c, 201 d.

The support cartridges are inserted into grooves 214b, 214c, 214d in perforated insulating plates 201a, 201b, 201c and 201d, one of which is hidden from view in fig. 2. The width of the groove is slightly larger than the wall thickness of the supporting cylinder, so that the supporting cylinder can be tightly fixed and plays a role in sealing. Because the whole device is placed in a vacuum environment, the sealing of the supporting cylinder and the perforated insulating plate is combined with the surrounding hole, the central hole, the ion emergent hole and the like which are all small in size, and the pressure difference of one order of magnitude between the inside and the outside of the ion trap cavity can be ensured. For better resolution, the optimum gas pressure inside the ion trap is about 0.1 to 0.5Pa and the gas pressure outside the ion trap is about 0.01 Pa. To maintain this pressure differential, the seal design of the present invention meets this requirement. In addition, better sealing also reduces the consumption of buffer gas and reduces the operating cost. The grooves on the first 201a and fourth 201d perforated insulator plates at the two ends of the device are made on one side, while the grooves on the second 201b and third 201d perforated insulator plates in the middle of the device are made on both sides.

Fig. 3 shows a hole pattern on a perforated insulating plate, comprising three types of holes. The first type of hole is a center hole 311, a metal ring is mounted on the center hole 311, and a voltage is applied to the metal ring to form a terminal electrode. Application of a suitable DC voltage to the metal ring enables control of ion transport along a central axis parallel to the wire electrodes. The second type of holes are 16 surrounding holes for the wire electrode to pass through, considering the simulation of the electromagnetic field and the control of the voltage applied on 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 with each other, the same alternating voltage is applied, the voltage amplitude is 10V to 10000V, and the wire electrode becomes a wire electrode. Four sets of surrounding holes, a first surrounding hole 312a, a second surrounding hole 312b, a third surrounding hole 312c and a fourth surrounding hole 312d, correspond to the four lead electrodes, respectively. The locations of the surrounding apertures may be symmetrical or asymmetrical with respect to the central location. The third type of holes are alignment holes 320 for aligning the position of these perforated insulating plates, which are symmetrical to the center of the plate.

The locations of the surrounding holes can be determined by simulation software calculations, and there are two location parameters for each hole location on the two-dimensional plane. For a symmetrical structure, the location of the symmetrical holes may be determined by symmetry. In the simulation software, thousands of ion runs were simulated in the apparatus to acquire mass spectra, and the locations of these small holes were optimized according to the resulting mass spectral resolution and sensitivity. Based on these criteria, the location of these pinholes can be completely determined. For example, in the case of a symmetrical embodiment using 16 holes, as shown in fig. 3, the positions of four holes are (6.7,0.7), (6.8,3), (1.5,7), (4.5,7), respectively, the center of the center hole is set to (0,0), and the remaining surrounding holes are positioned according to the principle of central symmetry. For an asymmetric structure, as shown in fig. 4, the positions of all these surrounding holes need to be calculated separately. The size of the ion trap can be scaled very easily according to practical requirements. The wire only needs to be 0.1mm to the machining precision requirement of encircleing the hole through encircleing the hole and can, and the machining precision of current four grades pole then need reach the micron level, and the processing degree of difficulty is big, and the processing cost is high, can't change after the machine-shaping moreover, and the wire electrode can be nimble change the perforated insulation board, with the hole distribution of encircleing of difference, constitutes different ion traps, has more industrial applicability.

Defining: the AV signal refers to a high-voltage alternating electric signal with the amplitude of 50V to 10000V, and the AC signal refers to a low-voltage alternating signal with the amplitude of 0-10V and the 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 two opposing sets of wire lead electrodes, e.g., the second lead electrode 316b and the fourth lead electrode 316 d. High-voltage alternating electrical signals AV having a phase difference of 180 ° are applied to the other pair of opposing groups, for example, the first wire electrode 316a and the third wire electrode 316 c. This alternating high voltage electrical signal AV provides a trapping electric field for the trapped ions. The amplitude of the high voltage alternating electrical signal is between 50V and 10000V. An alternating AV signal with a signal amplitude of less than 10V is additionally superimposed to the lead electrodes in the hole 316 a. Meanwhile, an electric signal of the same magnitude as that of the first wire electrode 316a by 180 degrees is applied to the third wire electrode 316 c. Similarly, such a low-voltage alternating AC signal having a phase difference of 180 ° may also be superimposed on the second lead electrode 316b and the fourth lead electrode 316 d. In addition, in addition to applying a low voltage AC signal, a constant potential difference of less than 10V needs to be applied across the first and third lead electrodes 316a and 316c, which can help the positive and negative ions to exit from the ion trap in opposite directions.

Fig. 4 shows another hole distribution structure of the perforated insulating plate. In this configuration, a central aperture 411 is provided in the central region of the perforated insulating plate. The 18 surrounding holes are divided into 6 groups of 3, each group of surrounding holes 412a, 412b, 412c, 412d, 412e, 412f are distributed around the central hole 411. Wherein a 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 412 e. High-voltage alternating voltage signals AV having the same amplitude and a phase difference of 180 degrees are applied to the lead electrodes passing through the second surrounding hole 412b, the fourth surrounding hole 412d and the sixth surrounding hole 412 f. The amplitude of the high voltage alternating voltage signal AV is between 50V and 10000V. The AV signal so applied can create a confining electric field in the cavity for trapping ions. The principle of the design is that the electric field formed by six groups of metal wire leads is similar to that in a hexapole ion transmitter and is used as an ion transmission device. Accordingly, the electric fields in an eight-pole ion transmitter and other multi-pole ion transmitters can be constructed in a similar manner based on the same principles. The number of the lead electrodes is an even number greater than 4.

Fig. 5 and 6 show the difference between the distribution of surrounding pores of a symmetric structure and the distribution of surrounding pores of an asymmetric structure. In the symmetrical surrounding pore structure of fig. 5, most ions exit equally from two opposite sides. In the asymmetric surrounding hole structure of fig. 6, however, the surrounding hole positions become asymmetric with respect to the central axis due to the shift of the surrounding hole positions, so that the one-way emission effect of ions can be obtained. Such a design of the asymmetrically surrounding aperture may yield more parameters to optimize the performance of the ion trap. Because of asymmetry, two parameters are added to the position of each hole, the performance can be better optimized, one ion detector can be reduced, the cost is reduced, and the detection sensitivity of the mass spectrometer is improved. Reference numeral in fig. 5, positioning hole-520, reference numeral in fig. 6, positioning hole-620.

Figure 7 shows the stretching means of the wire electrode. The design includes a wire fixing frame 718 and a number of hollow bolts 719. Wherein, a set of threaded holes 720 is provided on the wire fixing frame 718. The axis of the screw hole 720 forms an angle of 0 to 90 degrees with respect to the plane of the fixing plate 701, and the space can be effectively utilized by using multiple angles under the condition of insufficient space. The hollow bolt is installed in the screw hole 720. Each lead electrode passes through a through hole at the center of one of the hollow bolts 719, where the lead electrode is knotted or welded. The tensile force applied to the lead electrode can be determined by adjusting the rotational position of the hollow bolt 719. The design is simple and easy to use, and the tension can be independently adjusted for each lead electrode, so that the problem of uneven tension of the lead electrodes in the original design is solved.

Example 2, as shown in fig. 8 and 9.

Fig. 8 shows the structure of another ion control device. This structure uses three perforated insulating panels, a first perforated insulating panel 801a, a second perforated insulating panel 801b, a third perforated insulating panel 801c, with alignment holes 820, several sets of surrounding holes 812. Wherein the wire electrode between the first perforated insulator plate 801a and the second perforated insulator plate 801b forms the ion trapping chamber 803 and the wire electrode between the second perforated insulator plate 801b and the third perforated insulator plate 801c forms the ion mass analysis chamber 804. In the ion trap chamber, the surrounding aperture distribution pattern of the first insulating plate 801a is similar to that shown in fig. 4. In this design, the wire electrodes in the ion trapping chamber and the ion trap mass analysis chamber are independent of each other and are connected by a second perforated insulator plate 801b as shown in fig. 9. This design utilizes the surrounding aperture distribution structure of fig. 4, with a relatively large mass range of ions, thereby enabling an increase in the mass range of trapped ions.

Figure 9 shows a configuration of the surrounding aperture of the perforated insulating plate connecting two ion control devices. The central hole is located in the central area, the surrounding small holes are composed of two sets of small holes with different sizes and positions, and a set of front surrounding holes 913a, 913b, 913c, 913d, 913e, 913f are used for installing lead electrodes of the front-end ion capture chamber and are divided into six groups, wherein each group comprises three holes; another set of rear surrounding holes 912a, 912b, 912c, 912d was used to mount the lead electrodes of the rear ion analysis chamber, in four groups of 3. Three metal wires passing through the same group of surrounding holes are used as a wire electrode, the same voltage is applied, and the voltages applied by the adjacent wire electrodes belonging to the same ion control chamber have a phase difference of 180 degrees. The method comprises the following specific steps: two sets of AV signals having a phase difference of 180 degrees but the same amplitude are applied to the lead electrodes passing through the front surrounding holes 913a, 913c, 913e and the lead electrodes passing through the front surrounding holes 913b, 913d, 913f, respectively. Similarly, AV signals having a phase difference of 180 degrees but the same amplitude are applied to the lead electrodes passing through the rear surrounding holes 912a, 912c and the lead electrodes passing through the surrounding holes 913b, 913d, respectively. The distribution of these surrounding holes may be symmetrical or asymmetrical with respect to the centre of the perforated insulating plate, as shown in figures 5 and 6.

Example 3 was carried out as shown in fig. 10 and 11.

Fig. 10 shows the structure of another ion control device. In selected embodiments, three ion control devices are connected in series. The first and second perforated insulating plates 1033a and 1033b form an ion trapping chamber therebetween; the second and third perforated insulating plates 1033b and 1033c constitute an ion transport chamber; the third and fourth perforated insulating plates 1033c and 1033d constitute an ion analysis chamber. Two through holes are provided on the side wall of the first support cylinder 1036a to pass the ultraviolet light generated from the VUV lamps 1040a and 1040 b. Through holes 1038 are provided in the side wall of the second support cylinder 1036b to limit the air pressure within the cavity. A cutout is provided on a side wall of the third support cylinder 1036c to pass the emitted ions. The stretching means at one end includes a metal wire fixing frame 1041a and a set of fixing bolts 1037a thereon. The other end of the stretching device comprises a metal wire fixing frame 1041d and a set of fixing bolts 1037d thereon.

Fig. 11 shows the structure of another wire drawing device. In selected embodiments, the tensioning device includes a wire fixing frame 1140, a wire fixing block 1141 and a tension bolt 1142, and the tension of the wire is adjusted by the advance and retreat of the tension bolt 1142. Wherein, the electric wire fixed frame made by insulating material is equipped with three kinds of screw holes: reinforcement holes 1145, wire guides 1146, and holes 1147. The wire holes 1146 are used to pass metal wires therethrough so that they can be fixed by the wire fixing block 1141. The hole 1147 is internally threaded for receiving a tension bolt 1142 to provide pressure to the wire retention block 1141 by rotation. The reinforcement holes 1145 are used to mount the bolts to tighten the tension bolts 1142 to prevent movement of the wire tension bolts 1142. The wire fixing block 1141 has a through hole 1142 and a screw hole 1143, and the metal wire passes through the through hole 1142 and is fixed by a bolt 1148 to be installed in the screw hole 1143. The groove 1102 serves to maintain the position of the wire fixing block 1141.

Figure 12 shows another embodiment of the stretching assembly. The tension device 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 screw holes 1205 are provided in the frame. A wire tension bolt 1202 is mounted in the threaded hole 1205 to provide a tension force to the wire by rotating the tension bolt 1202. The wire fixing block 1203 fixes the wire by the wire fixing bolt 1204 being installed. Threaded hole 1206 is used to secure tension bolt 1202 against movement after the wire is tightened.

Example 4, as shown in figure 13.

In this embodiment, three ion control chambers are connected in series, an ion capture chamber 1310, an ion molecular reaction chamber 1311, and an ion analysis chamber 1312. The ion trap 1310 has a rectangular or circular through hole 1320 for connecting an ionization source, a sample gas inlet pipe and a buffer gas inlet pipe. Applying proper radio frequency voltage and direct current voltage on the lead electrode and the end electrode of the central hole of the perforated insulating plate to enable ions generated by the ion capture chamber to enter the ion molecule reaction chamber 1311 through the through hole in the center of the second perforated insulating plate, wherein the ion molecule reaction chamber is communicated with a buffer gas inlet pipe, the reacted ions enter the ion analysis chamber 1312 through the central hole in the third perforated insulating plate, a rectangular slit 1340 is arranged on a supporting cylinder of the ion analysis chamber to be connected with an ion detector, and a mass spectrogram of the reacted ions is obtained through the ion detector.

A configuration may be employed in which two ion control chambers are connected in series, wherein the ion trapping chamber 1310 that provides the sample ions may be replaced with another ion generating device, and the ions are transported to the ion molecular reaction chamber by means of an ion funnel or the like.

Wherein the ion molecular reaction chamber 1311 may also be used as a means for ion fragmentation, to fragment ions, which then re-enter the ion analysis chamber as a means for ion fragmentation.

Claims (11)

1. An ion control and mass analysis device, characterized by: the wire electrode structure comprises at least two supporting cylinders, perforated insulating plates, wire electrodes, a wire stretching device and an ion detector, wherein two ends of each supporting cylinder are respectively matched with one perforated insulating plate in a sealing mode to form a cavity, the wire electrodes are arranged in the cavity, a center hole is formed in the center of each perforated insulating plate, end electrodes are arranged on the perforated insulating plates, through holes are formed in the centers of the end electrodes, the positions of the through holes and the positions of the center holes are consistent, two ends of each wire electrode are respectively arranged on the front perforated insulating plate and the rear perforated insulating plate, and the ion.

2. The ion control and mass analysis device of claim 1, wherein: the perforated insulating plate is provided with at least four groups of surrounding holes, the wires pass through the surrounding holes to be fixed, and the wires fixed in the same group of surrounding holes form a wire electrode.

3. The ion control and mass analysis device of claim 2, wherein: each cavity is provided with four or more conductive line electrodes, each conductive line electrode is composed of at least two parallel conductive lines, and the conductive lines of the same conductive line electrode are applied with the same electric signal.

4. The ion control and mass analysis device of claim 1, wherein: the cavity surrounded by the supporting cylinder can be used as an ion capturing chamber, and a sample air inlet pipe and an ionization source are arranged on the supporting cylinder of the ion capturing chamber.

5. The ion control and mass analysis device of claim 3, wherein: each wire electrode is formed by the corresponding surrounding hole of the same metal wire which is turned back and forth to penetrate through the front perforated insulating plate and the rear perforated insulating plate.

6. The ion control and mass analysis device of claim 3, wherein: and the leads between the two adjacent cavities are communicated with each other or isolated from each other.

7. The ion control and mass analysis device of claim 6, wherein: the distribution conditions of the lead electrodes of the two adjacent cavities are kept consistent or different respectively.

8. The ion control and mass analysis device of claim 1, wherein: and the perforated insulating plate is provided with a groove matched with the supporting cylinder.

9. The ion control and mass analysis device of claim 4, wherein: the ionization source is an ultraviolet lamp, a point discharge, or a hot cathode electron emission source.

10. The ion control and mass analysis device of claim 9, wherein: the supporting cylinder is provided with a circular or rectangular through hole, and the through hole is used for introducing ultraviolet light or leading out ions.

11. The ion control and mass analysis device of claim 1, wherein: the cavity surrounded by the supporting cylinder can be used as an ion molecular reaction chamber or an ion fragmentation chamber.

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