An ion guiding technique

Abstract

The ion guiding technology provided by the present invention weakens particle collisions and improves the transmission efficiency by changing the flow field in the fluid channel. It also enables some non-target ions to deviate from the orbit by changing the electric field in the fluid channel, which can improve the signal-to-noise ratio of the detection signal. The ion transmission efficiency and the signal-to-noise ratio of the detection signal are high. Since the changes in the flow field and the electric field are both achieved through the adjustment parts provided on the electrodes surrounding the fluid channel, the steps are simple and the operation is convenient.

Description

Technical Field

[0001] The present invention belongs to the technical field of ion guiding technology. Background Art

[0002] Ion guiding technology is a technology that applies a radio frequency voltage to the electrodes surrounding a fluid channel, generates an electric field in the fluid channel by the electrodes to confine ions, and completes ion focusing and transmission together with front and rear lenses. It is widely used in chromatographic mass spectrometry coupling devices such as inductively coupled plasma mass spectrometry (ICP-MS), electrospray ionization mass spectrometry (ESI-MS), and atmospheric pressure chemical ionization mass spectrometry (APCI-MS), and plays a huge role in fields such as industrial production, environmental monitoring, health quarantine, poison detection, and explosive detection.

[0003] Generally speaking, the inlet end of the fluid channel is connected to the atmospheric environment, and the outlet end is connected to the vacuum environment. During the process of ion focusing and transmission, there is a high-speed gas flow in the fluid channel. Most of the traditional improvements to ion guiding technology focus on changing the shape of the electric field in the fluid channel to make ions have higher transmission efficiency, but do not consider the influence of the gas flow on ion transmission, and do not optimize and improve the flow field. When ions are transmitted, they will still collide due to the influence of the gas flow, resulting in deviation from the orbit and affecting the focusing and transmission effects. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an ion guiding technology with high ion transmission efficiency and capable of improving the signal-to-noise ratio of detection signals.

[0005] To achieve the above object, the technical solution adopted by the present invention is an ion guiding technology. This technology weakens particle collisions and improves transmission efficiency by changing the flow field in the fluid channel. This technology also changes the electric field in the fluid channel to make some non-target ions deviate from the orbit and improve the signal-to-noise ratio. The changes in the flow field and the electric field are both realized by adjusting parts provided on the electrodes surrounding the fluid channel.

[0006] Preferably, the electrode includes a strip-shaped sheet electrode.

[0007] More preferably, the adjusting part is arranged on the surface of the electrode facing the fluid channel.

[0008] More preferably, the adjusting part includes an adjusting groove opened on this surface. The adjusting groove extends outward in the radial direction of the fluid channel, and the adjusting groove also penetrates through both side surfaces of the electrode in the thickness direction of the electrode.

[0009] More preferably, the adjusting groove includes a blind groove, and the projection of the blind groove in the thickness direction of the electrode is rectangular, trapezoidal or arc-shaped.

[0010] Further preferably, the electrode is a multi-segment electrode, and the voltages applied to adjacent two segments of the electrodes decrease sequentially along the traveling direction of the target ions in the fluid channel.

[0011] Preferably, there are multiple adjusting parts on any of the electrodes, and the multiple adjusting parts are arranged at intervals.

[0012] Further preferably, the number of the adjusting parts on all the electrodes is equal and the positions correspond to each other.

[0013] Preferably, the diameter at the inlet of the fluid channel is not less than the diameter at the outlet.

[0014] Preferably, the included angle between the axis line of the fluid channel and the ion incident direction is an acute angle, so that at least a part of the neutral particles can deviate from the axis orbit.

[0015] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0016] The ion guiding technology provided by the present invention weakens particle collisions and improves the transmission efficiency by changing the flow field in the fluid channel, and also makes some non-target ions deviate from the orbit by changing the electric field in the fluid channel, improving the signal-to-noise ratio of the detection signal, so that the ion transmission has high efficiency and high signal-to-noise ratio. Since the changes in the flow field and the electric field are both realized by the adjusting parts provided on the electrodes surrounding the fluid channel, the modification of the ion guiding device is simpler and more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a perspective schematic diagram of a preferred ion guiding device applying the ion guiding technology of the present invention.

[0018] Figure 2 is Figure 1 a left view schematic diagram of [the above], and the dotted line shows the grouping situation of the electrodes.

[0019] Figure 3 is Figure 2 a cross-sectional schematic diagram taken along the A-A direction in [the above].

[0020] Figure 4 , Figure 5 is Figure 1 a front view schematic diagram of the electrode in [the above], showing trapezoidal and arc-shaped adjusting grooves.

[0021] Figure 6 , Figure 7 is Figure 3 a circuit schematic diagram of the voltage applied to the electrode in [the above], Figure 7 and the arrangement angles of the electrodes in [the above] are different.

[0022] Figure 8 , Figure 9It is the flow field distribution diagram at the left inlet of the electrode. Among them, Figure 8 is a round rod electrode, Figure 9 and is a long strip-shaped sheet electrode.

[0023] Figure 10 、 Figure 11 are respectively Figure 8 、 Figure 9 the flow field distribution diagrams at the longitudinal section.

[0024] Figure 12 is Figure 11 the transmission schematic diagram of non-target ions in the fluid channel in

[0025] Figure 13 is Figure 4 the electric field distribution diagram of the trapezoidal adjustment groove in

[0026] Figure 14 is the flow field schematic diagram at the unopened blind groove.

[0027] Figure 15 is the flow field schematic diagram at the blind groove.

[0028] Among them: 10. Fluid channel; 20. Electrode; 30. Adjustment groove; 40. Non-target ions; 51, 52, 53. Multi-stage ion lens. Specific implementation manners

[0029] The following combines the accompanying drawings to elaborate on the preferred embodiments of the present invention, so that the advantages and features of the present invention are more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0030] The ion guiding technology provided by the present invention is applied to Figures 1 to 7 the ion guiding device shown. This technology weakens particle collisions and improves the transmission efficiency by changing the flow field in the fluid channel 10. This technology also makes some non-target ions 40 deviate from the orbit by changing the electric field in the fluid channel 10, as Figure 12 shown, improving the signal-to-noise ratio of the detection signal. The changes in the flow field and the electric field are both realized through the adjustment parts provided on the electrode 20 surrounding the fluid channel 10.

[0031] This technology can not only achieve higher ion transmission efficiency and higher signal-to-noise ratio, but also is more simple and convenient to modify the ion guiding device during use.

[0032] Figure 8 、 Figure 10 shows the distribution of the flow field in the fluid channel surrounded by the round rod electrode. The air flow velocity in the fluid channel of the round rod electrode is distributed in a cross shape, and the velocity disperses outward. Figure 9 、 Figure 11shows the distribution map of the flow field in the fluid channel surrounded by strip-shaped sheet electrodes. The air flow velocity in the fluid channel of the strip-shaped sheet electrodes is circularly distributed, and the air flow is relatively concentrated. Compared with Figure 10 it can be seen that using the strip-shaped sheet electrode 20 can make the concentration degree of the flow field in the fluid channel 10 higher, can further improve the transmission efficiency, and avoid ion escape. Therefore, the electrode 20 is preferably a strip-shaped sheet electrode.

[0033] Further preferably, the adjusting part is arranged on the surface of the electrode 20 facing the fluid channel 10. The adjusting part includes an adjusting groove 30 opened on this surface. The adjusting groove 30 extends outward along the radial direction of the fluid channel 10 and is perpendicular to this surface. The adjusting groove 30 also penetrates through the two side surfaces of the electrode 20 along the thickness direction of the electrode 20. The adjusting groove 30 includes a blind groove. As Figures 4 to 6 shown, the projection of the blind groove in the thickness direction of the electrode 20 is in the shape of a rectangle, trapezoid or arc with an opening.

[0034] For the flow field, the blind groove avoids the area most likely to generate collisions and changes the movement trajectory of the fluid in this area. As Figure 15 shown, compared with Figure 14 , the blind groove reduces the collision angle between the particles and the wall surface, thereby reducing the collisions generated by the flow field for the particles and reducing the energy of the frontal impact during the collision, making the flow field have a more stable transmission and focusing effect and improving the transmission efficiency.

[0035] For the electric field, a potential well can be formed at the blind groove. As Figure 13 shown, it is more difficult for non-target ions to escape after entering the blind groove with the air flow. Even if they escape, they will deviate from the track and it is difficult to flow out from the outlet of the fluid channel 10, thereby improving the signal-to-noise ratio.

[0036] By changing the shape of the blind groove, different flow field and electric field shapes can be realized by using the different included angles between the two side walls of the blind groove and the axis line of the fluid channel 10, and different confinement and focusing effects can be generated. As Figure 4 and Figure 5 shown.

[0037] High-voltage direct current VD2 and radio frequency voltage RF are applied to every two columns of the electrodes as a group, and the adjacent two groups of electrodes are applied with radio frequency voltages in opposite directions, thereby generating a quadrupole field capable of confining ions. Preferably, the electrode 20 is a multi-segment electrode. By cooperating with a circuit composed of a resistor and a capacitor, as Figure 7 shown, the voltages applied to the adjacent two segments of the electrode 20 are sequentially reduced along the traveling direction of the target ions in the fluid channel 10, and multi-stage ion lenses 51, 52, 53 can be formed, generating a gradient voltage in space and obtaining a stronger ion focusing effect.

[0038] Furthermore, there are multiple adjustment parts on any electrode 20, and the multiple adjustment parts are arranged at intervals. The number of adjustment parts on all electrodes 20 is equal and their positions correspond to each other.

[0039] Preferably, as Figure 8 shown, by changing the tilt angle of the electrode 20, it is possible to make the diameter of the inlet of the fluid channel 10 not less than that of the outlet without the cooperation of the housing, thereby increasing the aggregation effect of ions.

[0040] Preferably, the angle between the axis of the fluid channel 10 and the ion incident direction is an acute angle, so that at least a part of the neutral particles can deviate from the axis orbit.

[0041] It should be noted that Figure 9 、 Figure 11 and Figure 12 the inclined surface at the left end of the electrode in

[0042] is for the housing with a taper angle and basically has no effect on changing the flow field and electric field. The above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. An ion guiding method, characterized in that: This method weakens particle collisions and improves transmission efficiency by changing the flow field in the fluid channel. This method also changes the electric field in the fluid channel to make some non-target ions deviate from the orbit and improve the signal-to-noise ratio. The changes in the flow field and the electric field are both realized by adjusting parts provided on the electrodes surrounding the fluid channel. The adjusting parts are provided on the surface of the electrodes facing the fluid channel side. The adjusting parts include adjusting grooves opened on this surface. The adjusting grooves extend outward in the radial direction of the fluid channel. The adjusting grooves include blind grooves.

2. The ion guiding method according to claim 1, characterized in that: The electrode includes a strip-shaped sheet electrode.

3. The ion guiding method according to claim 2, characterized in that: The adjusting groove also penetrates through both side surfaces of the electrode in the thickness direction of the electrode.

4. The ion guiding method according to claim 3, characterized in that: The projection of the blind groove in the thickness direction of the electrode is rectangular, trapezoidal or arc-shaped.

5. The ion guiding method according to claim 2, characterized in that: The electrode is a multi-segment electrode, and the voltages applied to adjacent two segments of the electrodes decrease sequentially along the traveling direction of the target ions in the fluid channel.

6. The ion guiding method according to claim 1, characterized in that: There are multiple adjusting parts on any of the electrodes, and the multiple adjusting parts are arranged at intervals.

7. The ion guiding method according to claim 6, characterized in that: The number of adjusting parts on all the electrodes is equal and the positions correspond to each other.

8. The ion guiding method according to claim 1, characterized in that: The diameter at the inlet of the fluid channel is not less than the diameter at the outlet.

9. The ion guiding method according to claim 1, characterized in that: The included angle between the axis line of the fluid channel and the ion incident direction is an acute angle, so that at least a part of the neutral particles can deviate from the axis orbit.

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