A high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry combined device

Abstract

The application discloses a high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry combined device, which comprises a sealed container, a pair of plane electrodes arranged in the sealed container, and the surfaces of the two electrodes of the pair of plane electrodes are perpendicular to an X axis; a plate Y electrode pair and a plate Z electrode pair are arranged between the pair of plane electrodes, the plate Y electrode pair and the plate Z electrode pair are composed of two rectangular plate-shaped electrodes which are arranged in parallel and are spaced apart, and the surfaces of the electrodes of the plate Y electrode pair and the plate Z electrode pair are perpendicular to a Y axis and a Z axis respectively; an ionization source, an ion outlet of the ionization source is above a region between a high-voltage electrode and a left end electrode and faces the region between the high-voltage electrode and the left end electrode; and a gas suction pump, a gas inlet of the gas suction pump extends into a region between the plate Y electrode pair or the plate Z electrode pair and the left end electrode through a wall surface of the sealed container. Through the pre-separation function of the high-field asymmetric waveform ion mobility spectrometry, non-target compound ions are prevented from entering the ion trap, so that the resolution and peak position stability of the ion trap are ensured.

Description

TECHNICAL FIELD

[0001] The application is a high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry device, which realizes two-dimensional separation analysis through cascade connection; the pre-separation of high-field asymmetric waveform ion mobility spectrometry is used to realize selective entry of ions into the ion trap and avoid peak broadening and peak shift caused by Coulomb effect in the ion trap. BACKGROUND

[0002] Ion mobility spectrometry is widely used in detection of chemical toxicants, drugs, stimulants, narcotics and explosives due to its high sensitivity, fast analysis speed and portability. Different ions have different flight times in a uniform field at atmospheric pressure, thereby realizing separation and analysis of different substances. High-field asymmetric waveform ion mobility spectrometry is a substance analysis and detection technology based on continuous development of traditional ion mobility spectrometry. It is based on changes in ion mobility in high-field (E / N>40Td, 1Td=10-17Vcm2) and low-field (E / N<2Td) to realize detection of different substances. The principle of asymmetric field ion mobility spectrometry is as follows: a carrier gas is used to make substance ions pass through a drift region vertically to the direction of the electric field, and the drift region is applied with an asymmetric field with positive and negative switching of radio frequency. In the whole radio frequency period, the time average of the voltage is zero. In this way, in the high-field and low-field sections, ions have a vertical displacement along the electric field with a mobility K, but if the mobility in the high-field and the low-field is different, the ions will overall leave the original position in the vertical direction and produce a net displacement in a cycle. After a certain time of accumulation, the displacement of the ions will make them hit the plate and be neutralized. In order to make the ions pass through the detection region smoothly, a direct current electric field can be superimposed on the original electric field. When the direct current electric field is appropriate, the net displacement of the ions in the vertical direction is zero, and then the ions can pass through the detection channel smoothly and be detected. By scanning the above direct current electric field, different ions can be detected.

[0003] High field asymmetric waveform ion mobility spectrometry can realize the separation of compounds with the same molecular weight but different structures, and can realize the separation and analysis of isomers in combination with mass spectrometry. In addition, in the field of protein analysis, high field asymmetric waveform ion mobility spectrometry can be used as a pre-separation front stage of mass spectrometry to eliminate low molecular weight compounds entering the mass spectrometer, greatly reduce background noise, improve signal-to-noise ratio, and increase sensitivity by 3 orders of magnitude. When the traditional high field asymmetric waveform ion mobility spectrometry is combined with mass spectrometry, only ions at a certain point can enter the mass spectrometer (Journal of the American Society for Mass Spectrometry 1999; 10: 492-501.), the ion utilization rate is low, and the sensitivity is poor. Then, in order to improve the ion utilization rate, a dome structure is proposed (Analytical Chemistry 2005; 77: 6381-6388). At present, high field asymmetric waveform ion mobility spectrometry combined with large bench-top instruments such as time-of-flight mass spectrometry and quadrupole mass spectrometry has been industrialized and popularized. However, there are few reports on the combination of high field asymmetric waveform ion mobility spectrometry with ion trap mass spectrometry. It is of great research significance and application prospect to realize the combination of high field asymmetric waveform ion mobility spectrometry with ion trap mass spectrometry. SUMMARY

[0004] The purpose of the present application is to combine micro high field asymmetric waveform ion mobility spectrometry with ion trap mass spectrometry, to solve the problem of accurate identification of target compounds in complex matrix during field application, and to avoid non-target compound ions entering the ion trap through the pre-separation function of high field asymmetric waveform ion mobility spectrometry, thereby ensuring the resolution and peak stability of the ion trap.

[0005] To achieve this purpose, the technical scheme adopted by the present application is as follows:

[0006] A high field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry combined device, comprising a closed container, a through hole is formed on the left side wall of the closed container; a pair of planar electrodes is arranged in the closed container, the pair of planar electrodes is composed of two parallel and spaced rectangular plate-shaped electrodes, and the four peripheral edges of the left side electrode of the pair of planar electrodes are in close contact with the inner wall of the through hole of the closed container, or one side surface of the left side electrode is in close contact with the container wall surface around the side opening end of the through hole of the closed container;

[0007] The direction from left to right is the X-axis direction, the direction from top to bottom is the Y-axis direction, and the direction perpendicular to the X-axis and the Y-axis is the Z-axis direction;

[0008] The two electrode surfaces of the planar end electrode pair are perpendicular to the X axis; a planar Y electrode pair is arranged between the planar end electrode pair, the planar Y electrode pair is composed of two rectangular plate-shaped electrodes arranged in parallel and spaced apart, and the electrode surfaces of the planar Y electrode pair are perpendicular to the Y axis; a planar Z electrode pair is arranged between the planar end electrode pair, the planar Z electrode pair is composed of two rectangular plate-shaped electrodes arranged in parallel and spaced apart, and the electrode surfaces of the planar Z electrode pair are perpendicular to the Z axis; and the area surrounded by the planar end electrode pair, the planar Y electrode pair and the planar Z electrode pair forms an ion trap area.

[0009] A radio frequency high voltage and an alternating current low voltage are applied to the planar Z electrode pair, and a radio frequency high voltage or ground voltage that is 180° out of phase with the radio frequency voltage of the Z electrode pair is applied to the planar Y electrode pair; the distance between the planar Z electrode pair is greater than the distance between the planar Y electrode pair; a slit corresponding to the middle part of one or both electrodes of the planar Z electrode pair is formed in the X axis direction, the slit is parallel to the X axis, and the slit penetrates the two side surfaces of the two electrodes perpendicular to the Z axis; and a direct current voltage is applied to the planar end electrode pair.

[0010] A through hole A serving as a sampling micro-hole is formed in the middle part of the left end electrode of the planar end electrode pair, the through hole A is located in the corresponding area of the through hole on the sealed container, that is, the sealed container can be connected to the outside through the sampling micro-hole to realize the regulation of the gas pressure on both sides.

[0011] A rectangular plate-shaped high-voltage electrode is arranged in parallel with the left side of the left end electrode, and the upper end edges of the left end electrode and the high-voltage electrode are aligned (i.e., on the same horizontal plane), and the lower end edge of the high-voltage electrode does not exceed the upper edge of the opening end of the sampling micro-hole on the left end electrode (i.e., the upper edge of the opening end, the horizontal plane where the lower end edge of the high-voltage electrode is located is the same as or above the horizontal plane where the upper edge of the opening end is located).

[0012] The area between the high-voltage electrode and the left end electrode of the planar end electrode pair forms an ion migration area.

[0013] An ionization source, the ion outlet of which is above the area between the high-voltage electrode and the left end electrode, and faces the area between the high-voltage electrode and the left end electrode.

[0014] A gas inlet of a gas pump extends through the wall of the sealed container into the area between the planar Y electrode pair or the planar Z electrode pair and the left end electrode.

[0015] The diameter of the sampling micro-hole is less than or equal to 1 mm, and the thickness of the end electrode is less than or equal to 1 cm; the gas pressure at the high-pressure end of the left side of the end electrode is in the range of 100 Pa to atmospheric pressure; and the gas pressure at the low-pressure end of the right side of the end electrode is lower than 10-1 Pa.

[0016] The low-pressure area is on one side of the flat Y electrode pair and the flat Z electrode pair (the side close to the left end electrode), and the high-pressure area is on the opposite side (the other side of the left end electrode).

[0017] The high-field asymmetric waveform voltage is applied to the high-voltage electrode, with a frequency of 0.1 MHz to 100 MHz, a high-field voltage of 1000 V to 10000 V, and a low-field voltage of 100 V to 500 V.

[0018] The frequency of the radio frequency high voltage is 0.5 MHz to 20 MHz, and the voltage amplitude is 1 kV to 5 kV.

[0019] The frequency of the alternating low voltage is 1 / 3 of the frequency of the radio frequency voltage, and the amplitude is 0.1 V to 5 V.

[0020] A direct current voltage is applied to the flat end electrode pair, with a voltage range of 1 to 50 V.

[0021] The distance between the left end electrode and the high-voltage electrode is less than or equal to 2 mm.

[0022] An ion detector is provided outside the ion trap area close to the slit, which can be one or more of an electron multiplier, a Faraday cup detector, a scintillation photomultiplier, and a microchannel plate detector.

[0023] The ionization source can be one or more of a single-photon ionization source, an electrospray ionization source, a discharge ionization source, and a radioactive ionization source.

[0024] Mobility change, mass-to-charge ratio, and intensity information can be provided to achieve accurate qualitative analysis. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 . High-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry combined device principle schematic diagram.

[0026] Ionization source (1), high-voltage electrode (2), left end electrode (3), sampling micropore (4), Y electrode pair (5, 5'), flat Z electrode pair (6, 6'), slit (7), right end electrode (3')

[0027] Figure 2 . High-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry combined device determines the typical spectrum of aniline (the upper graph is the result without high-field asymmetric waveform ion mobility spectrometry pre-separation, and the lower graph is the result with high-field asymmetric waveform ion mobility spectrometry). DETAILED DESCRIPTION

[0028] As Figure 1As shown, a high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry combined device includes a sealed container, a through hole is formed on the left side wall of the sealed container; a pair of planar electrodes 3, 3' are arranged in the sealed container, the pair of planar electrodes 3, 3' are composed of two rectangular plate-shaped electrodes arranged in parallel and spaced apart, and the four peripheral edges of the left side electrode 3 in the pair of planar electrodes 3, 3' are in close connection with the inner wall of the through hole on the sealed container, or the side surface of the left side electrode 3 is in close connection with the peripheral wall of the through hole on the sealed container;

[0029] The direction from left to right is the X-axis direction, the direction from top to bottom is the Y-axis direction, and the direction perpendicular to the X-axis and the Y-axis is the Z-axis direction;

[0030] The two electrode surfaces of the pair of planar electrodes 3, 3' are perpendicular to the X-axis; a pair of plate Y electrodes 5, 5' composed of two rectangular plate-shaped electrodes arranged in parallel and spaced apart are arranged between the pair of planar electrodes 3, 3', the electrode surfaces of the pair of plate Y electrodes 5, 5' are perpendicular to the Y-axis; a pair of plate Z electrodes 6, 6' composed of two rectangular plate-shaped electrodes arranged in parallel and spaced apart are arranged between the pair of planar electrodes 3, 3', the electrode surfaces of the pair of plate Z electrodes 6, 6' are perpendicular to the Z-axis; the area surrounded by the pair of planar electrodes 3, 3', the pair of plate Y electrodes 5, 5', and the pair of plate Z electrodes 6, 6' constitutes an ion trap area;

[0031] A radio frequency high voltage and an alternating current low voltage are applied to the pair of plate Z electrodes, and a radio frequency high voltage with a phase difference of 180° from the radio frequency voltage on the pair of Z electrodes or ground (grounded here) is applied to the pair of plate Y electrodes; the distance between the pair of plate Z electrodes 6, 6' is greater than the distance between the pair of plate Y electrodes 5, 5'; a corresponding slit 7 is formed in the middle of one of the pair of plate Z electrodes 6, 6' along the X-axis direction, the slit 7 is parallel to the X-axis, and the slit 7 penetrates the two side surfaces of the electrode perpendicular to the Z-axis; a direct current voltage is applied to the pair of planar electrodes 3, 3';

[0032] A through hole A (the through hole A is in the corresponding area of the through hole on the sealed container, that is, the sealed container is connected inside and outside through the sampling micro-hole 4) as a sampling micro-hole 4 is formed in the middle of the left side electrode 3 of the pair of planar electrodes 3, 3' for realizing the regulation of the gas pressure on both sides;

[0033] A rectangular plate-shaped high-voltage electrode 2 is arranged in parallel with the left side electrode 3 on the left side of the left side electrode 3, and the upper end edges of the left side electrode 3 and the high-voltage electrode 2 are aligned (that is, on the same horizontal plane), and the lower end edge of the high-voltage electrode 2 does not exceed the upper edge of the opening end of the sampling micro-hole 4 on the left side electrode 3 (that is, the upper edge of the opening end, the horizontal plane where the lower end edge of the high-voltage electrode 2 is located is the same as the horizontal plane where the upper edge of the opening end is located, or above the horizontal plane where the upper edge of the opening end is located);

[0034] The region between the high voltage electrode 2 and the left end electrode 3 of the pair of planar end electrodes 3, 3' constitutes an ion migration zone;

[0035] An ionization source, whose ion outlet is above the region between the high voltage electrode 2 and the left end electrode 3, facing the region between the high voltage electrode 2 and the left end electrode 3;

[0036] A gas inlet of a gas pump is extended through the wall of the sealed container to the region between the pair of planar Y electrodes 5, 5' or the pair of planar Z electrodes 6, 6' and the left end electrode 3.

[0037] The diameter of the sampling micro-hole 4 is equal to 0.3 mm, and the thickness of the end electrode 3 is equal to 3 mm; the gas pressure at the left high pressure end of the end electrode 3 is atmospheric pressure; the gas pressure at the right low pressure end of the end electrode 3 is 10 -3 Pa;

[0038] One side (or the side close to the left end electrode 3) of the pair of planar Y electrodes 5, 5' or the pair of planar Z electrodes 6, 6' is a low pressure region, and the opposite side (or the other side of the left end electrode 3) is a high pressure region.

[0039] An asymmetric high field waveform voltage is applied to the high voltage electrode 2, with a frequency of 1.5 MHz, a high field voltage of 3000 V, and a low field voltage of 500 V;

[0040] The frequency of the radio frequency high voltage is 1 MHz, and the voltage amplitude is 3 kV;

[0041] The frequency of the alternating low voltage is 1 / 3 of the frequency of the radio frequency voltage, and the amplitude is 0.1 V to 5 V.

[0042] A direct current voltage is applied to the pair of planar end electrodes 3, 3', and the voltage is 5 V.

[0043] The distance between the left end electrode 3 and the high voltage electrode 2 is equal to 0.8 mm.

[0044] An ion detector is arranged outside the ion trap region close to the slit 7, and the ion detector is a Faraday cup detector.

[0045] The ionization source can be an electrospray ionization source.

[0046] The migration rate, mass-to-charge ratio and intensity information can be provided to realize accurate qualitative analysis. The focused ion migration tube measures aniline: under the action of purified air, aniline is ionized by an acetone assisted VUV photochemical ionization source 1, enters a high field asymmetric field ion migration zone between a high voltage electrode 2 and a left side electrode 3 under the action of a carrier gas, and is pre-separated; under the action of a pressure difference, the sample micropore 4 enters an ion trap mass analyzer composed of a Y electrode pair (5, 5'), a flat plate Z electrode pair (6, 6'), and an end electrode pair (3, 3'), and finally is detected by a detector after passing through a slit 7 under the action of an axial excitation electric field. Figure 2 )

Claims

1. A high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometer device, characterized in that: comprising a closed container, a through hole is formed on the left side wall of the closed container; a pair of planar end electrodes (3, 3') is arranged in the closed container, the pair of planar end electrodes (3, 3') is composed of two rectangular plate-shaped electrodes arranged in parallel and spaced apart, and the four peripheral edges of the left end electrode (3) in the pair of planar end electrodes (3, 3') are in close connection with the inner wall of the through hole on the closed container, or the side surface of the left end electrode (3) is in close connection with the peripheral edge of the opening end of the through hole on the closed container; the direction from left to right is the X-axis direction, the direction from top to bottom is the Y-axis direction, and the direction perpendicular to the X-axis and the Y-axis is the Z-axis direction; the surfaces of the two electrodes of the pair of planar end electrodes (3, 3') are perpendicular to the X-axis; a pair of plate Y electrodes (5, 5') composed of two rectangular plate-shaped electrodes arranged in parallel and spaced apart is arranged between the pair of planar end electrodes (3, 3'), the surfaces of the electrodes of the pair of plate Y electrodes (5, 5') are perpendicular to the Y-axis; a pair of plate Z electrodes (6, 6') composed of two rectangular plate-shaped electrodes arranged in parallel and spaced apart is arranged between the pair of planar end electrodes (3, 3'), the surfaces of the electrodes of the pair of plate Z electrodes (6, 6') are perpendicular to the Z-axis; the region surrounded by the pair of planar end electrodes (3, 3'), the pair of plate Y electrodes (5, 5'), and the pair of plate Z electrodes (6, 6') constitutes an ion trap region; a radio frequency high voltage and an alternating current low voltage are applied to the pair of plate Z electrodes, and a radio frequency high voltage or ground voltage with a phase difference of 180° from the radio frequency voltage of the pair of Z electrodes is applied to the pair of plate Y electrodes; the distance between the pair of plate Z electrodes (6, 6') is greater than the distance between the pair of plate Y electrodes (5, 5'); a corresponding slit (7) is formed in the middle of one or both electrodes of the pair of plate Z electrodes (6, 6') along the X-axis direction, the slit (7) is parallel to the X-axis, and the slit (7) penetrates the two side surfaces of the two electrodes perpendicular to the Z-axis; a direct current voltage is applied to the pair of planar end electrodes (3, 3'); a through hole A serving as a sampling micro-hole (4) is formed in the middle of the left end electrode (3) of the pair of planar end electrodes (3, 3') for regulating the gas pressure on both sides, and the through hole A is located in the corresponding region of the through hole on the closed container, that is, the inside and outside of the closed container are connected through the sampling micro-hole (4); a rectangular plate-shaped high-voltage electrode (2) is arranged in parallel with the left end electrode (3) on the left side of the left end electrode (3), and the upper end edges of the left end electrode (3) and the high-voltage electrode (2) are aligned, the lower end edge of the high-voltage electrode (2) does not exceed the upper edge of the opening end of the sampling micro-hole (4) on the left end electrode (3), that is, the opening end upper edge, the horizontal plane where the lower end edge of the high-voltage electrode (2) is located is the same as the horizontal plane where the opening end upper edge is located, or is above the horizontal plane where the opening end upper edge is located; an ion mobility region is formed in the region between the high-voltage electrode (2) and the left end electrode (3) of the pair of planar end electrodes (3, 3'). ​ ​ ​ ​ An ionization source (1) with its ion exit above the region between the high voltage electrode (2) and the left end electrode (3) and facing the region between the high voltage electrode (2) and the left end electrode (3); A gas inlet of a gas pump is extended through the wall of the sealed container to the region between the flat plate Y electrode pair (5, 5') or the flat plate Z electrode pair (6, 6') and the left end electrode (3).

2. The high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry device of claim 1, wherein: The diameter of the sampling micro-hole (4) is less than or equal to 1 mm, and the thickness of the left end electrode (3) is less than or equal to 1 cm; the air pressure range of the left high air pressure end of the left end electrode (3) is 100 Pa to atmospheric pressure; the air pressure of the right low air pressure end of the left end electrode (3) is less than 10 Pa - 1 . The side of the flat plate Y electrode pair (5, 5') or the flat plate Z electrode pair (6, 6') close to the left end electrode (3) is a low pressure region, and the side opposite to the low pressure region is a high pressure region.

3. The high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry device of claim 1, wherein: The high-field asymmetric waveform voltage is applied to the high voltage electrode (2) with a frequency of 0.1 MHz to 100 MHz, a high-field voltage of 1000 V to 10000 V, and a low-field voltage of 100 V to 500 V; The frequency of the radio frequency high voltage is 0.5 MHz to 20 MHz, and the voltage amplitude is 1 kV to 5 kV; The frequency of the alternating current low voltage is 1 / 3 of the frequency of the radio frequency voltage, and the amplitude is 0.1 V to 5 V.

4. The high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry device of claim 1, wherein: A direct current voltage is applied to the flat end electrode pair (3, 3') with a voltage range of 1 to 50 V.

5. The high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry device of claim 1, wherein: The distance between the left end electrode (3) and the high voltage electrode (2) is less than or equal to 2 mm.

6. The high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry device of claim 1, wherein: An ion detector is provided outside the ion trap region close to the slit (7), and the ion detector is one or more than two of an electron multiplier, a Faraday cup detector, a scintillation photomultiplier, and a microchannel plate detector.

7. The high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry device of claim 1, wherein: The ionization source is one or more than two of a single photon ionization source, an electrospray ionization source, a discharge ionization source, and a radioactive ionization source.

8. The high-field asymmetric waveform ion mobility spectrometry-ion trap mass spectrometry device of claim 1, wherein: The mobility change, mass-to-charge ratio, and intensity information are provided to realize accurate qualitative analysis.

Images