An ion kinetic energy modulation component and a time-of-flight mass analyzer having the same

Abstract

The present invention discloses an ion kinetic energy modulation component, which includes a housing, a pole rod mounting cylinder and a pole rod. The housing has a housing inlet and a housing outlet. The pole rod mounting cylinder is arranged inside the housing. The pole rod is disposed through the inside of the pole rod mounting cylinder. The pole rod is provided with an ion channel through it. The ion channel has an ion channel inlet and an ion channel outlet. The present invention discloses a time-of-flight mass analyzer, which includes the above ion kinetic energy modulation component. The present invention realizes the conversion of the time-of-flight mass analyzer between two modes. In the single reflection mode, high-speed, high-sensitivity and high-resolution analysis of samples can be achieved. In the triple reflection mode, ultra-high-resolution analysis of samples can be achieved. The two working modes of a single mass analyzer can be realized to meet various different detection requirements, achieving a balance between analysis speed, sensitivity and resolution.

Description

Technical Field

[0001] The present invention belongs to the technical field of analysis and detection of charged ions, and particularly relates to an ion kinetic energy modulation component and a time-of-flight mass analyzer having the same. Background Art

[0002] A time-of-flight mass analyzer determines the mass-to-charge ratio of different charged ions according to the different flight times of the ions in vacuum. Under a certain accelerating electric field, the kinetic energy obtained by the ions is the same. The larger the mass-to-charge ratio of the ions, the slower the speed, and the longer the time required to fly the same distance. A time-of-flight mass analyzer is a high-resolution mass analyzer. In order to increase the resolution, it is usually necessary to increase the flight path of the ions, thereby increasing the overall flight time. Considering that the physical size of the analyzer cannot be extended infinitely, a reflectron time-of-flight mass analyzer is generally used, which can not only increase the flight path without changing the overall structural size, but also allow ions with high kinetic energy to penetrate deeper and spend more time returning to the detector than ions with slower flight times. This enables ions with different initial velocities to reach the detector together, obtaining better kinetic energy focusing conditions, thereby improving the resolution of the mass analyzer. However, the longer the flight distance, the more ions are lost, the worse the sensitivity of the mass analyzer, and the slower the analysis speed. Once a single-mode mass analyzer is designed, the flight distance of the ions is already determined, and it is impossible to dynamically balance the sensitivity and resolution, which greatly limits the application range of the single-mode time-of-flight mass analyzer.

[0003] In summary, the present application now proposes an ion kinetic energy modulation component and a time-of-flight mass analyzer having the same to solve the above problems. Summary of the Invention

[0004] In order to solve the above deficiencies in the prior art, the purpose of the present invention is to provide a time-of-flight mass analyzer that can switch between single reflection and triple reflection modes to meet different detection requirements.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0006] According to the ion kinetic energy modulation component of an embodiment of the present invention, it includes: a housing having a housing inlet and a housing outlet; a pole mounting cylinder disposed inside the housing; and poles penetrating through the pole mounting cylinder, the poles being provided with ion channels having an ion channel inlet and an ion channel outlet.

[0007] According to the ion kinetic energy modulation component of an embodiment of the present invention, the poles and the housing form a gradient electric field in the axial direction, and the electric field can be regulated by controlling the amplitude of the electric signal, thereby realizing the acceleration or deceleration of the ions.

[0008] In some embodiments, the pole mounting cylinder has a cylindrical structure.

[0009] In some embodiments, the cross-sectional area of the ion channel inside the pole is smaller closer to the ion channel inlet.

[0010] In some embodiments, the housing is connected to an external gas source, and a mass flow controller is provided in the gas path of the external gas source.

[0011] In some embodiments, it further includes: a shielding cover having an ion inlet, the ion kinetic energy modulation assembly is located inside the shielding cover, and an opening connected to a molecular pump is provided on the side wall of the shielding cover.

[0012] In some specific embodiments, it further includes: a quadrupole lens provided inside the shielding cover and located on the side of the housing away from the ion inlet of the shielding cover. The quadrupole lens has a quadrupole lens inlet and a quadrupole lens outlet. The cross-section of the quadrupole lens inlet is circular, and the cross-section of the quadrupole lens outlet is linear.

[0013] In some specific embodiments, it further includes: an ion repulsion pulse electrode provided inside the shielding cover and located on the side of the quadrupole lens away from the ion inlet. The ion repulsion pulse electrode includes a repulsion pole shielding shell having a shielding shell inlet and a shielding shell outlet; and a repulsion pole plate located inside the repulsion pole shielding shell.

[0014] A time-of-flight mass analyzer according to an embodiment of the present invention includes the ion kinetic energy modulation assembly described above.

[0015] In some specific embodiments, it further includes: a second reflector including a reflector shielding cover which is a trough having a trough ion inlet; a second bottom plate provided inside the reflector shielding cover and away from the trough ion inlet; a second lens provided inside the reflector shielding cover and close to the trough ion inlet; a fourth electrode provided inside the reflector shielding cover and close to the second lens; and a third electrode provided between the second bottom plate and the fourth electrode.

[0016] According to the time-of-flight mass analyzer of the embodiments of the present invention, the acceleration or deceleration of ions is achieved through an ion kinetic energy modulation component. When the ions are accelerated through the ion kinetic energy modulation component, the time-of-flight mass analyzer detects the ions in the single mode. When the ions are decelerated through the ion kinetic energy modulation component, the time-of-flight mass analyzer detects the ions in the triple mode. The conversion between the two modes of the time-of-flight mass analyzer can be achieved as needed. In the single reflection mode, high-speed, high-sensitivity, and high-resolution analysis of samples can be achieved. In the triple reflection mode, ultra-high-resolution analysis of samples can be achieved. The two working modes of the single mass analyzer can be realized to meet various different detection requirements, and a balance between analysis speed, sensitivity, and resolution can be achieved.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Brief Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the time-of-flight mass analyzer in the embodiments of the present invention;

[0019] Figures 2 - 4 It is a schematic structural diagram of the ion kinetic energy modulation component in the embodiments of the present invention;

[0020] Figures 5 - 7 It is a schematic structural diagram of the quadrupole lens in the embodiments of the present invention;

[0021] Figure 8 It is a schematic diagram of the flight trajectory of ions in the single mode in the embodiments of the present invention;

[0022] Figure 9 It is a schematic diagram of the flight trajectory of ions in the triple mode in the embodiments of the present invention.

[0023] 11. Shield cover ion inlet; 12 Shield cover;

[0024] 21. Quadrupole lens;

[0025] 211. Quadrupole lens inlet; 212. Arc electrode plate; 213. Quadrupole lens outlet;

[0026] 22. Mass flow controller; 23. Outer shell; 24. Pole;

[0027] 241. Ion channel inlet; 242. Ion channel outlet; 243. Pole mounting cylinder;

[0028] 31. Repeller shield case; 32. Repeller plate; 33. Ion acceleration electrode; 34. Flight tube;

[0029] 41. First lens; 42. First electrode; 43. Second electrode; 44. First base plate;

[0030] 51. First shield; 52. Second lens; 53. Third electrode; 54. Second base plate; 55. Fourth electrode;

[0031] 61. Detector; 62. Anode electrode piece; 63. High-speed data acquisition card assembly. Detailed implementation manners

[0032] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention, rather than limiting the invention. Additionally, it should be noted that for the convenience of description, only the parts related to the invention are shown in the drawings.

[0033] Next, according to Figures 1 - 9 to describe the specific structure of the ion kinetic energy modulation component of the embodiment of the present invention.

[0034] As Figures 1 - 7 shown, the ion kinetic energy modulation component according to the embodiment of the present invention includes a housing 23, a pole 24, a shield 12, a quadrupole lens 21, and an ion repulsion pulse electrode.

[0035] As Figures 2 - 4As shown, the outer shell 23 has an outer shell inlet and an outer shell outlet. The outer shell inlet is used to introduce ions to be analyzed. The outer shell inlet is preferably a round hole with a pore diameter less than 1 mm. The pole mounting cylinder 243 is arranged inside the outer shell 23. The pole mounting cylinder 243 is in a cylindrical structure. The pole mounting cylinder 243 is preferably a metal cylinder. The pole 24 is arranged through the inside of the pole mounting cylinder 243. The pole 24 is preferably six groups. The six groups of poles 24 are arranged in a circular array inside the pole mounting cylinder 243. The pole 24 is provided with an ion channel through it. The ion channel has an ion channel inlet 241 and an ion channel outlet 242. A direct current signal is applied to the outer shell 23, and a radio frequency signal with a frequency of about 1 MHz is applied to the pole 24. At the same time, a direct current signal is also applied to the pole 24. The cross-sectional area of the ion channel inside the pole 24 is smaller closer to the ion channel inlet 241. The pole 24 combined with the outer shell 23 can form an electric field with a gradient change in the axial direction. By controlling the amplitude of the electric signal (-300 - 300 V), the electric field can be regulated, thereby realizing the acceleration or deceleration of ions (positive ions are accelerated by applying negative voltage, decelerated by applying positive voltage; negative ions are decelerated by applying negative voltage, accelerated by applying positive voltage). The outer shell 23 is connected to an external gas source. The gas path of the external gas source is provided with a mass flow controller 22. The external gas source introduces inert gases (such as nitrogen, argon, etc.) into the ion kinetic energy modulation module. At the same time, the mass flow controller 22 on the gas path dynamically regulates the gas flow rate. The gas flow rate is less than 1 ml / min. By reasonably controlling the flow rate of the inflowing gas, the ion collision focusing effect can be achieved, reducing the spatial dispersion of ions. The shielding cover 12 has an ion inlet. The ion kinetic energy modulation component is located inside the shielding cover 12. The side wall of the shielding cover 12 is provided with an opening connected to a molecular pump. The molecular pump is preferably a turbomolecular pump, which can ensure the vacuum environment inside the shielding cover 12.

[0036] As Figures 5 - 7 , the quadrupole lens 21 is arranged inside the shielding cover 12, and the quadrupole lens 21 is located on the side of the outer shell 23 away from the ion inlet 11 of the shielding cover. The quadrupole lens 21 has a quadrupole lens inlet 211 and a quadrupole lens outlet 213. The cross-section of the quadrupole lens inlet 211 is circular, and the cross-section of the quadrupole lens outlet 213 is linear. The quadrupole lens inlet 211 is circular to introduce the ions flying out of the kinetic energy modulation module. The quadrupole lens 21 is preferably composed of four arc-shaped electrode plates 212. Different direct current signals are applied to the four arc-shaped electrode plates to compress the cylindrical ion beam into a flat ion beam and lead it out from the quadrupole lens outlet 213.

[0037] The ion repulsion pulse electrode is arranged inside the shield 12, and the ion repulsion pulse electrode is located on the side of the quadrupole lens 21 away from the ion inlet. The ion repulsion pulse electrode includes a repulsion pole shield case 31 and a repulsion pole plate 32. The repulsion pole shield case 31 has a shield case inlet and a shield case outlet. The repulsion pole plate 32 is located inside the repulsion pole shield case 31. The shield case inlet is used to introduce ions that have passed through the quadrupole lens 21. A pulsed high-voltage signal with the same polarity as the ions is applied to the repulsion pole plate 32 to eject the ions. The time when the pulsed high voltage is applied is used as the starting point for counting the ion flight time. The ions fly out of the repulsion pole shield case 31 through the shield case outlet.

[0038] Embodiment 1

[0039] The time-of-flight mass analyzer according to the embodiment of the present invention includes the aforementioned ion kinetic energy modulation component, a flight tube 34, an ion acceleration electrode 33, a first reflector, a second reflector, a detector 61, an anode electrode plate 62, and a high-speed data acquisition card component 63.

[0040] The ion acceleration electrode 33 has an inlet and an outlet. The inlet of the ion acceleration electrode 33 corresponds to the shield case outlet and is used to introduce ions that have passed through the repulsion pole plate 32. The ion acceleration electrode 33 is composed of a plurality of annular electrode plates distributed at equal intervals. Each annular electrode plate is connected by a high-voltage-resistant resistor to form a uniform acceleration electric field.

[0041] The flight tube 34 has an inlet and an outlet. The inlet of the flight tube 34 corresponds to the outlet of the ion acceleration electrode 33. The inlet of the flight tube 34 is used to introduce ions that have passed through the ion acceleration electrode 33.

[0042] The first reflector includes a first lens 41, a first electrode 42, a second electrode 43, and a first bottom plate 44. The first lens 41 is an Einzel lens composed of three circular ring electrode plates. After the ions are accelerated by the pole 24 of the ion kinetic energy modulation component, they finally enter the flight tube 34. After being focused by the first lens 41, they fly into the first reflector. The first electrode 42 is composed of a plurality of stacked circular ring electrode plates. The plurality of circular ring electrode plates are connected by equal-value high-voltage-resistant resistors to form a uniform reflection electric field. A direct current signal is applied separately to the second electrode 43, and an electric signal is applied separately to the first bottom plate 44. The first reflector is divided into two uniform deceleration electric fields by the second electrode 43. The ions gradually decelerate after entering the first electrode 42, further decelerate after passing through the second electrode 43, and the longitudinal velocity of the ions becomes 0 before reaching the first bottom plate 44. Subsequently, under the action of the internal electric field of the first reflector, the ions move in the reverse direction to complete ion reflection and fly out of the first reflector. The ions leave the flight tube 34 from the outlet of the flight tube 34 and reach the detector 61.

[0043] The detector 61 is composed of two identical MCR detectors 61 stacked on top of each other. An anode electrode plate 62 is placed behind the MCR detector 61, preferably four independent anode electrode plates 62. The amplified ion signal is collected by the high-speed data acquisition card assembly 63 and subtracted from the voltage application time on the pulse repulsion electrode to obtain the flight time of the ions.

[0044] In the embodiment of the present invention, it is in a single reflection working mode, and the movement trajectory of the ions is as Figure 8 shown. The ions only undergo one reflection. The ion movement path is shorter, the ion loss is less, the sensitivity is higher, and the analysis speed is fast.

[0045] Embodiment 2

[0046] The time-of-flight mass analyzer according to the embodiment of the present invention, different from Embodiment 1, further includes a second reflector. The second reflector includes a first shielding cover 51, a second lens 52, a third electrode 53, a fourth electrode 55, and a second bottom plate 54.

[0047] The first shielding cover 51 isolates the mutual penetration influence of the internal and external electric fields. The second lens 52 has the same structural principle as the first lens 41. The third electrode 53 has the same structural principle as the first electrode 42. The fourth electrode 55 has the same structural principle as the second electrode 43. The second bottom plate 54 has the same structural principle as the first bottom plate 44.

[0048] After the ions are decelerated by the poles 24 of the ion kinetic energy modulation assembly, they fly into the first reflector of the flight tube 34. The ions flying out of the first reflector will fly towards the second reflector due to their relatively low axial kinetic energy of the ions. Similar to the principle of the first reflector, before reaching the second bottom plate 54, the longitudinal velocity of the ions becomes 0, and then they move in the reverse direction under the action of the electric field of the second reflector to complete ion reflection. Finally, the ions fly out of the second reflector and fly into the first reflector. Similar to the principle in Embodiment 1, the longitudinal velocity of the ions becomes 0, and they move in the reverse direction under the action of the electric field of the first reflector, and finally fly into the detector 61 through the outlet of the flight tube 34.

[0049] In this embodiment, the movement trajectory of the ions is as Figure 9 shown. The ions undergo three reflections. The ion movement path is longer, the ion loss is more, the sensitivity is lower, and the analysis speed is slower. Due to the increase in the flight path, the ions in this embodiment can obtain ultra-high resolution analysis.

[0050] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0051] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solution formed by mutually replacing the above features with (but not limited to) technical features having similar functions disclosed in the present application.

[0052] Except for the technical features described in the specification, the remaining technical features are known to those skilled in the art. To highlight the innovative features of the present invention, the remaining technical features will not be elaborated herein.

Claims

1. An ion kinetic energy modulation component, characterized in that, Comprising: A housing (23) having a housing inlet and a housing outlet; A pole mounting cylinder (243) disposed inside the housing (23); And A pole (24) passing through the inside of the pole mounting cylinder (243), the pole (24) being provided with an ion channel therethrough, the ion channel having an ion channel inlet (241) and an ion channel outlet (242), and the cross-sectional area of the ion channel inside the pole (24) being smaller closer to the ion channel inlet (241); The pole mounting cylinder (243) has a cylindrical structure; A DC signal is applied to the housing (23), and an RF signal with a frequency of 1 MHz and a DC signal are applied to the pole (24). The cross-sectional area of the ion channel inside the pole (24) is smaller closer to the ion channel inlet (241), so that a gradient-changing electric field is formed in the axial direction by the pole (24) in combination with the housing (23), and an electric signal with an amplitude of -300 - 300 V is controlled to regulate the electric field, so that ions are accelerated or decelerated.

2. The ion kinetic energy modulation component according to claim 1, characterized in that The housing (23) is connected to an external gas source, and a mass flow controller (22) is provided in the gas path of the external gas source.

3. The ion kinetic energy modulation component according to claim 1, characterized in that Further comprising: A shield (12) having an ion inlet, the ion kinetic energy modulation assembly being located inside the shield (12), and an opening connected to a molecular pump being provided on the side wall of the shield (12).

4. The ion kinetic energy modulation component according to claim 3, wherein Further comprising: A quadrupole lens (21) disposed inside the shield (12), and the quadrupole lens (21) is located on the side of the housing (23) away from the shield ion inlet (11). The quadrupole lens (21) has a quadrupole lens inlet (211) and a quadrupole lens outlet (213), the cross-section of the quadrupole lens inlet (211) is circular, and the cross-section of the quadrupole lens outlet (213) is linear.

5. The ion kinetic energy modulation component according to claim 4, characterized in that, Further comprising: An ion repulsion pulse electrode disposed inside the shield (12), and the ion repulsion pulse electrode is located on the side of the quadrupole lens (21) away from the ion inlet. The ion repulsion pulse electrode includes: A repulsion pole shield (31) having a shield inlet and a shield outlet; And A repulsion pole plate (32) located inside the repulsion pole shield (31).

6. A time-of-flight mass analyzer, characterized in that, Comprising the ion kinetic energy modulation assembly according to any one of claims 1 - 5 above.

7. The time-of-flight mass analyzer according to claim 6, wherein Further comprising: A second reflector, the second reflector comprising: A reflector shield (12) which is a trough having a trough ion inlet; A second bottom plate (54) disposed inside the reflector shield (12) and away from the trough ion inlet; A second lens (52) disposed inside the reflector shield (12) and close to the trough ion inlet; A fourth electrode (55) disposed inside the reflector shield (12) and at a position close to the second lens (52); A third electrode (53), the third electrode (53) being disposed between a second base plate (54) and a fourth electrode (55).

Images