A multi-functional ion transport device and method

Abstract

The present invention relates to mass spectrometry technology, and specifically provides a multifunctional ion transmission device and method. The ion transmission device includes a multipole rod and an ion lens; the AC rod includes multiple segments extending along a direction parallel to the ion transmission direction; a power supply loads an AC voltage to the multiple segments according to a working mode and a mapping relationship, and the mapping relationship is a corresponding relationship between the working mode and the loaded AC voltage; the gas output by the gas supply unit enters the multipole rod and flows against the ion transmission direction. The present invention has advantages such as reducing pollution and is applied in mass spectrometry analysis.

Description

Technical Field

[0001] The present invention relates to mass spectrometry technology, and particularly to a multifunctional ion transmission device and method. Background Art

[0002] The working principle of a mass spectrometer is as follows: Ionized analytes are generated in the source, and the analyte ions are transported from the atmospheric pressure ion source through several differential vacuum regions to high vacuum, and finally the mass-to-charge ratio (m / z) of the sample and the corresponding signal intensity are measured. The movement of ions from one position to another in the instrument, where the ions obtain energy axially through the vacuum gradient and the electric potential gradient, lose energy by colliding with the background gas, and finally when the axial movement energy is positive, the ions can continue to move backward. Radially, mainly by applying RF radio frequency voltage and static voltage to various ion optical devices to establish an electric field, radially restricting the central ion path of the ions, and ensuring that the ions move axially from a higher electric potential energy region to a lower electric potential energy region, so that the ions can continue to be transported backward in a state of high transmission efficiency and reach the detector.

[0003] In the above mass spectrometry analysis process, the following aspects need to be concerned:

[0004] 1. These ion optical devices must be kept clean, otherwise the phenomenon of "charge accumulation" usually occurs, resulting in a decline in instrument performance, such as a decrease in sensitivity and a change in resolution.

[0005] 2. With the development of mass spectrometry technology, more fragmentation information is required. Therefore, it is necessary for the transmission device to also have the function of ion fragmentation.

[0006] 3. Charged ions often cluster with other substances (such as substances that can contain substances such as salts or solvent molecules or dust, etc.), and have different physicochemical properties from the ideal analyte ions (different mass-to-charge ratios and different ion mobilities). Therefore, it is necessary to remove the clustered ions from the analyte ions before mass screening of the analyte ions.

[0007] To solve the above technical problems, the prior art usually adopts the following solutions.

[0008] 1. Pass heated counter gas between the sampling cone and the baffle, and apply a resonance voltage to the sampling cone to reduce the condensation clustering caused by the expanding jet. The disadvantages of this solution are as follows:

[0009] The efficiency of loading the resonance voltage onto the clusters is not high and there is no high pertinence; and there is still a probability of re-clustering after passing through the sampling cone.

[0010] 2. When contamination occurs, conduct a comprehensive cleaning and maintenance of the ion optical lens system of the instrument. The disadvantages of this solution are as follows:

[0011] The disassembly and assembly of a mass spectrometry instrument is extremely troublesome, and it cannot be restored to its original state. It also requires complex debugging and takes a long time.

[0012] 3. In a triple quadrupole mass spectrometer, ion fragmentation usually occurs in a collision cell. The disadvantages of this solution are as follows:

[0013] The collision cell is located in the middle of two quadrupole mass analyzers. It can only perform one collision fragmentation, and the obtained fragmentation information is limited. Moreover, it is impossible to perform cluster dissociation at the front end of the mass analyzer to achieve the effect of reducing the contamination of the mass analyzer, which is the core component of the mass spectrometer. Summary of the Invention

[0014] To solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a multifunctional ion transmission device.

[0015] The object of the present invention is achieved through the following technical solutions:

[0016] A multifunctional ion transmission device includes a multipole rod and an ion lens; the ion transmission device further includes:

[0017] An AC rod, which includes multiple segments extending along a direction parallel to the ion transmission direction;

[0018] A power supply, which loads an AC voltage on the multiple segments according to the working mode and the mapping relationship, and the mapping relationship is the corresponding relationship between the working mode and the loaded AC voltage;

[0019] A gas supply unit, and the background gas output by the gas supply unit enters the multipole rod and flows against the ion transmission direction.

[0020] The object of the present invention also lies in providing a working method for an ion transmission device, and this object of the invention is achieved through the following technical solutions.

[0021] The working method of the ion transmission device of the present invention is as follows:

[0022] The power supply loads an AC voltage on the multiple segments according to the working mode and the mapping relationship, and the mapping relationship is the corresponding relationship between the working mode and the loaded AC voltage;

[0023] The gas supply unit outputs gas as needed, and the gas enters the multipole rod and flows against the ion transmission direction.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. A mapping relationship between the working mode and the amplitude of the voltage applied to the AC rod is established. By controlling the amplitude of the voltage applied to the AC rod to adjust the working mode, multifunctionality (working mode) is achieved;

[0026] For example, by controlling the magnitude of the AC characteristic frequency and the AC voltage amplitude, the ion transport effect can be precisely controlled to achieve the cleavage of ions / clusters, and it has higher-level ion fragment information compared with traditional triple quadrupole mass spectrometers.

[0027] 2. Compared with traditional transfer rods, it has the function of isolating contaminants such as clusters, macromolecules, and charged dust from entering the next-stage mass spectrometer, effectively improving the anti-pollution ability of the mass spectrometer.

[0028] 3. By controlling the timing of the ion lens voltage, the ion optical device where charge accumulation leads to reduced sensitivity can be accurately located. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Referring to the accompanying drawings, the disclosure of the present invention will become more readily understood. It is easily understood by those skilled in the art that these drawings are only used to illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention. In the figures:

[0030] Figure 1 is a schematic structural diagram of an ion transport device for reducing mass spectrometry pollution according to the present invention;

[0031] Figure 2 is a schematic structural diagram of an ion transport device for reducing mass spectrometry pollution according to the present invention;

[0032] Figure 3 is a schematic structural diagram of an ion transport device for reducing mass spectrometry pollution according to the present invention;

[0033] Figure 4 is a schematic structural diagram of an ion transport device for reducing mass spectrometry pollution according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] Figures 1 - 4 The following description and examples describe alternative specific embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. To teach the technical solutions of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art should understand that variations or substitutions derived from these specific embodiments will fall within the scope of the present invention. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following alternative specific embodiments, but is only defined by the claims and their equivalents.

[0035] Example 1.

[0036] A multifunctional ion transport device in this embodiment, as Figure 1 shown, includes a quadrupole 11 and an ion lens.

[0037] The two AC rods 21 are of a multi-segment structure and are successively arranged in a direction parallel to the ion transmission direction. The two AC rods 21 are arranged between adjacent poles of the quadrupole 11. In a cross-section perpendicular to the ion transmission direction, the centers of the AC rods 21 are on the perpendicular bisector of the line connecting the centers of the adjacent poles 11, and the angles between the tangents of the AC rods 21 passing through the pole centers and the said line are all 45 degrees.

[0038] The power supply loads an AC voltage for the multi-segment according to the working mode and the mapping relationship, and the mapping relationship is the corresponding relationship between the working mode and the loaded AC voltage.

[0039] The background gas output by the gas supply unit enters the quadrupole 11 and flows against the ion transmission direction.

[0040] The said mapping relationship is:

[0041] In the selective band-pass mode, the ratio D of the amplitude of the loaded AC voltage to the amplitude of the boundary voltage is 0.8 < D ≤ 1. The cluster of corresponding mass-to-charge ratios cannot move stably in the radial direction and will be discharged from the quadrupole 11 by the AC resonance energy.

[0042] In the selective collision dissociation mode, the ratio D of the amplitude of the loaded AC voltage to the amplitude of the boundary voltage is 0 < D ≤ 0.8. The cluster of corresponding mass-to-charge ratios and the target ions oscillate in the radial direction, causing the ions of the current mass-to-charge ratio to oscillate. At the same time, they collide with the introduced background gas, separating the adduct molecules from the analyte ions, making the cluster smaller, and the target ions dissociate into daughter ions to obtain fragment information.

[0043] Ion transmission mode: The ratio D of the amplitude of the loaded AC voltage to the amplitude of the boundary voltage is D = 0 for ion transmission.

[0044] The said boundary voltage is:

[0045] 。

[0046] When A ≥ 300, 。

[0047] When A < 300, 。

[0048] fac is the frequency of the boundary voltage, with the unit of kHz; A is the mass-to-charge ratio, with the unit of amu; r0 is the field radius of the quadrupole 11, V rf is the radio frequency amplitude of the poles of the quadrupole 11, with the unit of V; V ac is the amplitude of the boundary voltage, with the unit of V.

[0049] e is a constant, an exponential decay term, which compensates for the edge field effect of the quadrupole 11 and the high-order harmonic interference.

[0050] Reflect the non-linear effect of the radio frequency voltage on Vac.

[0051] Reflect the negative correlation effect with Vac when the mass increases.

[0052] Compensate for the field distortion effect in the low-mass region.

[0053] The working method of the ion transport device according to the embodiment of the present invention is as follows:

[0054] The power supply applies the multi-segment loaded AC voltage according to the working mode and the mapping relationship, and the mapping relationship is the corresponding relationship between the working mode and the loaded AC voltage;

[0055] The gas supply unit outputs gas as needed, and the gas enters the quadrupole 11 and flows against the ion transport direction.

[0056] The data of this embodiment is shown in the following table:

[0057] The field radius r0 of the quadrupole 11 is 6 mm, V rf The frequency is 1.25 MHz.

[0058] .

[0059] Embodiment 2.

[0060] A multi-functional ion transport device and method according to an embodiment of the present invention, which is different from Embodiment 1.

[0061] As Figure 2 shown, through the voltage division of the capacitor 31, a gradient is formed in the AC electric field on the ion transport channel: the amplitude of the AC voltage gradually becomes smaller, because as the cluster moves along the AC rod 21 and the adduct ions fall off through resonance, the mobility of the cluster often increases. Therefore, reducing the resonance energy of the AC voltage along the AC rod 21 helps to prevent these ions from oscillating with a large amplitude and causing ion loss.

[0062] The gas supply unit introduces background gas at the rear end of the quadrupole 11 region and flows against the ion transport direction, improving the resonance efficiency and ion transport efficiency.

[0063] An AC voltage smaller than that in Embodiment 1 is applied on the AC rod, and it is usually recommended to be adjustable below 80% of the boundary voltage, so that the target cluster / ion oscillates greatly in the stable region in the radial direction of the transport rod, increasing the collision probability between the ion and the background gas, and causing the target cluster / ion to crack. The specific cracking state can be dynamically adjusted by fine-tuning the AC voltage corresponding to the target ion.

[0064] This embodiment is used to detect reserpine 609.25 - 195, and the boundary voltage data is shown in the following table:

[0065] The field radius r0 of the quadrupole 11 is 6 mm, V rf The frequency is 1.25 MHz.

[0066] 。

[0067] Example 3.

[0068] A multifunctional ion transport device and method according to an embodiment of the present invention, different from Embodiment 1 is that

[0069] As Figure 3 shown, the multi - segment AC rod 21 and the quadrupole 11 are shared, and RF voltage and AC voltage are applied on multiple segments.

[0070] The data of this embodiment is as follows:

[0071] The field radius r0 of the quadrupole 11 is 6 mm, V rf The frequency is 1.25 MHz.

[0072] All AC voltages are set to 0 and used as a traditional ion transport device.

[0073] Example 4.

[0074] A multifunctional ion transport device and method according to an embodiment of the present invention, different from Embodiment 3 is that

[0075] As Figure 4 shown, through voltage division by the capacitor 31, an AC electric field gradient is formed on the ion transport channel: the amplitude of the AC voltage gradually becomes smaller. As the cluster moves along the AC rod 21 and the adduct ions are shed through resonance, the mobility of the cluster often increases. Therefore, reducing the resonance energy of the AC voltage along the AC rod 21 helps to prevent these ions from oscillating with a large amplitude and causing ion loss.

[0076] Example 5.

[0077] A multifunctional ion transport device and method according to an embodiment of the present invention, different from Embodiment 4 is that

[0078] As Figure 4 shown, by the method of segmented voltage division, the combined effect of cluster / ion ejection and fragmentation is adjusted.

[0079] For example, the target cluster / ion can be ejected in the first half of the transport rod, and the remaining ions can be fragmented in the second half, which can effectively reduce the chemical noise interference after fragmentation;

[0080] The voltages applied to the first half of the AC rod are shown in the following table:

[0081] 。

[0082] The voltages applied to the second half of the AC rod are shown in the following table:

[0083] 。

[0084] Example 6.

[0085] A multifunctional ion transport device and method according to an embodiment of the present invention, different from Embodiment 5 in that

[0086] As Figure 4 shown, cluster / ion cleavage can be performed in the first half of the transport rod, and the discharged target clusters / ions after cleavage can be performed in the second half.

[0087] The voltages applied to the first half of the AC rod are shown in the following table:

[0088] 。

[0089] The voltages applied to the second half of the AC rod are shown in the following table:

[0090] 。

[0091] Example 7.

[0092] An ion transport device for reducing mass spectrometry contamination according to an embodiment of the present invention, different from Embodiment 2 in that:

[0093] Three ion lenses are used, and a quadrupole rod and an AC rod are arranged between adjacent ion lenses.

[0094] The ion transport method of this embodiment further includes a detection stage, and the detection stage includes steps:

[0095] (A1) Positive ions pass through devices such as three ion lenses and a quadrupole rod, are received by the detector, and a first signal A1 is obtained.

[0096] (A2) Negative ions pass through the transport device and are blocked by the i-th (usually taking the maximum or minimum) ion lens 41 in the selected ion transport direction, i = 1, 2, 3.

[0097] (A3) Positive ions pass through multiple ion lenses, are received by the detector, and a second signal A2 is obtained;

[0098] (A4) Determine whether the difference between the second signal A2 and the first signal A1 exceeds a threshold value. For example, the threshold value is 20% of the first signal A1;

[0099] If the result is yes, there is contamination in the transport device upstream of the selected ion lens. Perform steps (A1)-(A4), and use the (i-1)-th ion lens in the ion transport direction as the selected ion lens.

[0100] Cycle in the above manner. If the judgment result is no, there is contamination in the device between the selected ion lens corresponding to this judgment result and the i-th ion lens.

[0101] If the result is no and the transport device is normal, perform steps (A1)-(A4), and use the (i+1)-th or (i-1)-th ion lens in the ion transport direction as the selected ion lens.

[0102] Cycle in the above manner. If the judgment result is yes, there is contamination in the device between the two previously selected ion lenses with opposite judgment results.

[0103] For example, in the above detection stage, if i = 1 and the judgment result is yes, there is contamination in the device upstream of the first ion lens. If the judgment result is no, cycle as above and use the (i+1)-th ion lens as the selected ion lens to traverse all ion lenses.

[0104] For example, in the above detection stage, if i = 3 and the judgment result is yes, there is contamination in the device upstream of the third ion lens. Cycle as above and use the (i-1)-th ion lens in the ion transport direction as the selected ion lens to traverse all ion lenses. If the judgment result is no, it indicates that there is no contamination (charge accumulation) in the ion transport device.

Claims

1. A multifunctional ion transport device, comprising a multipole rod and an ion lens; characterized in that, The ion transport device further includes: an AC rod, which includes multiple segments extending along a direction parallel to the ion transport direction; a power supply, which loads an AC voltage on the multiple segments according to the working mode and the mapping relationship, and the mapping relationship is the corresponding relationship between the working mode and the loaded AC voltage; a gas supply unit, and the background gas output by the gas supply unit enters the multipole rod and flows against the ion transport direction; The mapping relationship is as follows: In the selective bandpass mode, the ratio D of the amplitude of the loaded AC voltage to the amplitude of the boundary voltage is 0.8 < D ≤ 1. Clusters corresponding to the mass-to-charge ratio cannot move stably in the radial direction and will be discharged from the multipole rod by the AC resonance energy; In the selective collision dissociation mode, the ratio D of the amplitude of the loaded AC voltage to the amplitude of the boundary voltage is 0 < D ≤ 0.

8. Clusters corresponding to the mass-to-charge ratio and target ions oscillate in the radial direction, causing the ions of the current mass-to-charge ratio to oscillate, while colliding with the background gas, separating the adduct molecules from the analyte ions, making the clusters smaller, and splitting the target ions into daughter ions to obtain fragment information; Ion transport mode: The ratio D of the amplitude of the loaded AC voltage to the amplitude of the boundary voltage is D = 0 for ion transport; The boundary voltage is: ； When A ≥ 300, ; When A < 300, ; fac is the frequency of the boundary voltage, A is the mass-to-charge ratio, r0 is the multipole rod field radius, V rf is the radio frequency amplitude of the rod, V ac is the amplitude of the boundary voltage.

2. The ion transport device according to claim 1, characterized in that, In the selective collision dissociation mode, along the direction parallel to the ion transport direction, the amplitude of the voltage loaded on the multiple segments becomes smaller.

3. The ion transport device according to claim 1, characterized in that, The AC rod is arranged between adjacent poles of the multipole rod. In the cross-section perpendicular to the ion transport direction, the center of the AC rod is on the perpendicular bisector of the line connecting the centers of the adjacent poles, and the angles between the tangents of the AC rod passing through the centers of the adjacent poles and the line are both 45 degrees.

4. The ion transport device according to claim 1, wherein The AC rod is shared with the multipole rod, and a radio frequency voltage is loaded on the multiple segments.

5. A working method of the ion transport device according to any one of claims 1-4, and the working method is: The power supply loads an AC voltage on the multiple segments according to the working mode and the mapping relationship, and the mapping relationship is the corresponding relationship between the working mode and the loaded AC voltage; The gas supply unit outputs gas as needed, and the gas enters the multipole rod and flows against the ion transport direction.

6. The working method according to claim 5, characterized in that The working method further includes a detection stage, and the detection stage includes the steps: (A1) Positive ions pass through N ion lenses and are received by the detector to obtain a first signal A1; a multipole rod is arranged between adjacent ion lenses; N is an integer greater than 2; (A2) Negative ions pass through the transport device and are blocked by the i-th ion lens in the selected ion transport direction, where i = 1, 2 ··· N; (A3) Positive ions pass through multiple ion lenses and are received by the detector to obtain a second signal A2; (A4) Determine whether the difference between the second signal A2 and the first signal A1 exceeds the threshold; If the result is yes, there is contamination in the upstream transport device of the selected ion lens; If the result is no, the transport device is normal.

7. The working method according to claim 6, characterized in that, If the result is no, execute steps (A1)-(A4), and the (i + 1)-th or (i - 1)-th ion lens in the ion transport direction is used as the selected ion lens; Cycle in the above manner. If the judgment result is yes, there is contamination in the device between the two selected ion lenses with opposite judgment results before and after. If the result is yes, perform steps (A1)-(A4), and the (i-1)-th ion lens in the ion transport direction is used as the selected ion lens; Loop in the above manner. If the judgment result is no, there is contamination in the device between the selected ion lens corresponding to the judgment result and the i-th ion lens.

8. The working method according to claim 6, characterized in that, If i = 1 and the judgment result is yes, there is contamination in the device upstream of the first ion lens.

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