Ionization device and method

Abstract

The application provides an ionization device and method, which comprises a housing and an electrospray ion source, the outlet of the electrospray ion source is arranged on the housing; a plurality of gas inlets surround the ion source and are arranged on the first side of the housing; a filtering unit is arranged in the housing and is located between the opposite first side and second side of the housing, the outlet of the ion source is located between the filtering unit and a gas outlet; an adjusting unit is used to directly or through the filtering unit to connect the spaces on both sides of the filtering unit; a gas outlet is arranged on the second side of the housing; and a negative pressure generating unit is connected to the gas outlet. The application has the advantages of high detection signal-to-noise ratio and fast cooling.

Description

TECHNICAL FIELD

[0001] The present application relates to ionization, in particular to ionization devices and methods. BACKGROUND

[0002] Electrospray ionization technology can ionize non-volatile solutions in a relatively simple method, and can accurately quantify the molecular weight of high mass molecules, so it is widely used in mass spectrometry technology. However, due to the presence of solvent particles in the electrospray generation process, the signal sensitivity of mass spectrometry is reduced, and mass spectrometry is contaminated.

[0003] In order to reduce the influence of solvent molecules on the detection accuracy of mass spectrometry, a high-temperature auxiliary gas is usually introduced at the electrospray ion source to achieve desolvation by heating the spray. At this time, since the solvent particles are not charged, they will not be affected by the electric field force and enter the cone capillary, thereby improving the signal strength of the target ions. However, since the auxiliary gas needs to be heated, the ion source shell has a very high temperature, and it needs to wait for about half an hour before disassembly after stopping work. In addition, after desolvation, the solvent particles are scattered in the ion source shell, and part of the solvent will still enter the mass spectrometer with the target ions, thereby affecting the signal sensitivity.

[0004] In view of the above problems, the usual technical solution is to passively exhaust the solvent particles by connecting a waste gas pipe under the shell to exhaust the solvent particles, but this method has the following disadvantages:

[0005] Only part of the direct blowing waste gas can be exhausted, and part of the waste gas remains, and the ion source cannot be quickly cooled. Active air exhaust can also be performed under the shell, which can exhaust more waste gas from the ion source shell, but waste gas still remains, and the ion source cannot be cooled. SUMMARY

[0006] In order to solve the above problems in the prior art, the present application provides an ionization device.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] The ionization device comprises a shell and an electrospray ion source, and the electrospray ion source is arranged on the shell; the ionization device further comprises:

[0009] A gas inlet, a plurality of gas inlets surround the ion source, and are arranged on the first side of the shell with the electrospray ion source;

[0010] A filter unit is arranged in the shell and is located between the first side and the second side of the shell, and the outlet of the ion source is located between the filter unit and the gas outlet.

[0011] an adjusting unit for directly or through the filtering unit connecting the spaces on both sides of the filtering unit;

[0012] a gas outlet provided on the second side of the shell;

[0013] a negative pressure generating unit connected to the gas outlet.

[0014] Another object of the present application is to provide an ionization method, and the object is achieved by the following technical scheme:

[0015] The ionization method comprises the following steps:

[0016] An ionization stage, in which a sample is ionized by an ion source, a spray is formed at the outlet of the ion source, and the outlet of the ion source is located in the shell between the filtering unit and the second side of the shell;

[0017] A carrier gas enters the shell from a plurality of gas inlets on the first side of the shell, then passes through the filtering unit, carries the sheath gas and auxiliary gas discharged from the outlet, and is discharged from the gas outlet on the second side; the second side and the first side are oppositely arranged;

[0018] A cooling stage, in which the ion source is turned off, the carrier gas enters the shell from the plurality of gas inlets, does not pass through the filtering unit, and carries the gas in the shell to be discharged from the gas outlet.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. High signal-to-noise ratio of ion detection;

[0021] During detection, the carrier gas sequentially passes through the gas inlet, the filtering unit and the gas outlet, forming a low-speed uniform unidirectional flow, avoiding vortex of hot volatile solvent gas, background gas, purge gas and the like in the ion source cavity, eliminating particle residues and generating poor pollution, and improving the signal-to-noise ratio of detection;

[0022] 2. Fast cooling;

[0023] When the ion source stops working, the filtering unit no longer filters the carrier gas (the filtering unit rotates or the carrier gas bypasses the filtering unit), thereby forming a high-speed unidirectional flow, rapidly purging high-temperature gas, and cooling the shell, thereby accelerating cooling;

[0024] 3. Low energy consumption;

[0025] The gas supply flow and the gas extraction flow are controlled by a pressure sensor and the like, thereby realizing collaborative and efficient control and reducing energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0026] The disclosure of the present application will become more fully understood from the detailed description given herein below and the accompanying drawings. It should be understood that the drawings are not to scale and are merely intended to illustrate the technical solutions of the present application. In the drawings:

[0027] Figure 1 is a structural schematic diagram of an ionization device according to an embodiment of the present application;

[0028] Figure 2 is a structural schematic diagram of an ionization device according to an embodiment of the present application;

[0029] Figure 3 is a structural schematic diagram of an ionization device according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] Figures 1-3 The optional embodiments of the present application are described in the following description and accompanying drawings to teach those skilled in the art how to make and use the present application. Some of the features have not been described in detail in order not to unnecessarily obscure the present application. Those skilled in the art will understand that variations or modifications of the embodiments described can be made without departing from the scope of the present application. Those skilled in the art will understand that features described in the following description can be combined in a variety of ways to form multiple variations of the present application. Therefore, the present application is not limited to the optional embodiments described in the following description. Rather, the scope of the present application is defined by the claims and their equivalents.

[0031] Embodiment 1

[0032] The structural diagram of the ionization device according to Embodiment 1 of the present application is shown in Figure 1 The ionization device comprises:

[0033] a housing 11 forming an enclosed space, and an electrospray ion source 21 disposed on the housing 11;

[0034] a plurality of gas inlets 31 surrounding the ion source 21 and disposed on the first side 12 of the housing 11 with the electrospray ion source 21;

[0035] a filter unit 61 disposed within the housing 11 between the first side 12 and the second side 13 of the housing 11 opposite to each other, and an outlet of the ion source 21 between the filter unit 61 and a gas outlet 32;

[0036] an adjusting unit for directly or through the filter unit 61 connecting the spaces on both sides of the filter unit 21;

[0037] a gas outlet 32 disposed on the second side 13 of the housing 11;

[0038] A negative pressure generating unit 41 is in communication with the gas outlet 32.

[0039] In order to improve the discharge efficiency of solvent particles and reduce the temperature as soon as possible, further, the ionization device further comprises a control unit, the control unit comprises:

[0040] A pressure sensing module 51 obtains the gas pressure in the housing 11 and the pressure difference ΔP at the gas outlet 32.

[0041] A judgment module is used to judge whether the pressure difference is greater than a threshold value, and the output result is sent to the control module; the threshold value is C1(m1+m2) 2 -C2(m1+m2), m2 is the flow rate through the gas inlet 31, m1 is the flow rate of the outlet gas of the ion source 21, C1 and C2 are coefficients respectively;

[0042] The control module is used to close the negative pressure generating unit when the judgment result is yes, and open the negative pressure generating unit 41 when the judgment result is no.

[0043] In order to discharge the solvent particles in the housing 11, further, the flow rate through the gas inlet 31 satisfies m2:

[0044] m2=C3A 2 -C4A+C5m1+C6, A is the ratio of the cross-sectional area of the gas outlet 32 to the area of the second side 13, C3, C4, C5 and C6 are coefficients respectively.

[0045] In order to reduce the structural complexity, further, the gas outlet 32 comprises a first outlet 321, the central axis of the first outlet 321 and the central axis of the outlet of the ion source 21 are collinear.

[0046] In order to make the carrier gas enter the housing 11 without passing through the filtering unit 61, further, as Figure 1 shown, the adjusting unit comprises:

[0047] A pipeline 71 and a switch valve, the input end of the pipeline 71 is in communication with the space in the housing 11 between the filtering unit 61 and the gas inlet 31, the output end is in communication with the space in the housing 11 between the filtering unit 61 and the gas outlet 32, and the switch valve is arranged on the pipeline 71.

[0048] In order to make the carrier gas flow in the housing 11 without passing through the filtering unit 61, further, the adjusting unit comprises:

[0049] a driving module for driving the filtering unit 61 to rotate around the rotation shaft.

[0050] The ionization method of the embodiment of the application is:

[0051] In the ionization stage, the sample is ionized by the ion source 21, and a spray is formed at the outlet of the ion source 21, which is located in the housing between the filtering unit 61 and the second side 13 of the housing 11.

[0052] The carrier gas enters the housing 11 from the plurality of gas inlets 31 at the first side 12 of the housing, then passes through the filtering unit 61, carries the sheath gas and auxiliary gas discharged from the outlet, and is discharged from the gas outlet 32 at the second side 13; the second side 13 and the first side 12 are oppositely arranged.

[0053] In the cooling stage, the ion source 21 is closed, the carrier gas enters the housing 11 from the plurality of gas inlets 31, does not pass through the filtering unit 61, and carries the gas in the housing 11 to be discharged from the gas outlet 32.

[0054] In order to start the air extraction and cool down as soon as possible, further, the pressure sensing module 51 obtains the gas pressure in the housing 11 and the pressure difference ΔP at the gas outlet 32.

[0055] The judging module judges whether the pressure difference is greater than a threshold value, and outputs the result to the control module; the threshold value is C1(m1+m2) 2 -C2(m1+m2), m2 is the flow rate through the gas inlet 31, m1 is the flow rate of the gas discharged from the outlet of the ion source 21, C1 and C2 are coefficients, and the coefficients are obtained by simulation calculation, in which the ratio of the ion source gas vortex area to the height of the cone is less than 0.8, and the pressure and flow rate are recorded without using outlet air extraction, and the curve fitting is obtained;

[0056] The control module closes the negative pressure generating unit 41 when the judgment result is yes, and opens the negative pressure generating unit when the judgment result is no, and the negative pressure generating unit 41 is connected to the gas outlet 32.

[0057] In order to discharge the solvent particles in the housing 11, further, the flow rate through the gas inlet 31 satisfies m2:

[0058] m2=C3A 2 -C4A+C5m1+C6, A is the ratio of the cross-sectional area of the gas outlet 32 to the area of the second side 13, and C3, C4, C5 and C6 are coefficients, and the values are obtained by simulation calculation, in which m1, m2 and A are fitted when the ratio of the ion source gas vortex area to the height of the cone is less than 0.8.

[0059] Example 2

[0060] Application examples of the ionization apparatus and method according to Embodiment 1 of the present invention.

[0061] like Figure 1 As shown, the first side 12 of the housing 11 is the upper side, and the second side 13 is the lower side, arranged opposite each other. The ion source 21 is an electrospray ion source, fixed on the first side 12, below the outlet filter unit 61. The filter unit 61 includes multiple filters, disposed within the housing 11. Multiple gas inlets 31 are disposed on the first side 12, surrounding the ion source 21. The gas outlet 32 ​​includes a first outlet 321 and other outlets surrounding the first outlet 321, the central axis of the first outlet 321 and the outlet central axis of the ion source 21 are in the same plane. An adjustment unit is used to drive the filters to rotate around a pivot.

[0062] The output end of gas outlet 32 ​​is connected to negative pressure generating unit 41, which employs a vacuum pump. Waste gas treatment unit 42 is connected to negative pressure generating unit 41 and is used to treat the gas discharged from housing 11.

[0063] The pressure sensing module 51 detects the gas pressure at the housing 11 and the gas outlet 32, and obtains the pressure difference ΔP. The judgment module is used to determine whether the pressure difference is greater than a threshold, and outputs the result to the control module; the control module is used to turn off the negative pressure generating unit 41 when the judgment result is yes, and turn on the negative pressure generating unit 41 when the judgment result is no.

[0064] The threshold value = C1(m1 + m2) 2 -C2(m1+m2), m2=C3A 2 -C4A+C5m1+C6, where m1 is the flow rate of the gas discharged from the outlet of ion source 21, and C1 is 6.7×10. 5 -7.3×10 5 In this embodiment, 7.0 × 10 5 C2 takes a value between 4.0 and 6.0, and in this embodiment, it takes a value of 5.0; C3 takes a value between 0.20 and 0.23, and in this embodiment, it takes a value of 0.22; C4 takes a value between 0.033 and 0.035, and in this embodiment, it takes a value of 0.035; C5 takes a value between 160 and 175, and in this embodiment, it takes a value of 168; and C6 takes a value of 0.0011.

[0065] m1 = 6.25 × 10 -5 kg / s, A=0.227, we can get m2=0.0150kg / s, threshold=158.7Pa.

[0066] The ionization method of this embodiment of the invention, that is, the working process of the ionization device of this embodiment, is as follows:

[0067] During the ionization stage, the sample is ionized by ion source 21, and a spray is formed at the outlet of ion source 21.

[0068] The carrier gas enters the housing 11 through multiple gas inlets 31 on the first side 12 of the housing, then passes through the filter unit 61, carrying the sheath gas and auxiliary gas discharged from the outlet of the ion source 21, and is discharged from the gas outlet 32 ​​on the second side 13; the second side 13 and the first side 12 are arranged opposite to each other;

[0069] During the cooling phase, the ion source 21 is shut off, and the carrier gas enters the housing 11 through the multiple gas inlets 31. The regulating unit drives the filter to rotate around the axis, as shown in the case of a vertical arrangement. Figure 2 As shown, the carrier gas flows downward without being blocked by the filter, that is, it does not pass through the filter unit 61, and carries the gas in the housing 11 out of the gas outlet 32;

[0070] During the above stage, the pressure sensing module 51 obtains the gas pressure inside the housing 11 and the pressure difference ΔP at the gas outlet 32;

[0071] The judgment module determines whether the pressure difference is greater than a threshold, and sends the result to the control module; the threshold is C1(m1+m2). 2 -C2(m1+m2) =158.7Pa;

[0072] If the judgment result is yes, the control module shuts down the negative pressure generating unit 41; in this embodiment, ΔP=159.5 Pa, the negative pressure generating unit 41 is shut down; the simulation results show that the carrier gas can effectively discharge solvent particles and prevent solvent particles from remaining in the shell;

[0073] If the judgment result is negative, the control module turns on the negative pressure generating unit 41.

[0074] Example 3

[0075] An application example of the ionization apparatus and method according to Embodiment 1 of the present invention differs from that in Embodiment 2 in that:

[0076] 1. For example Figure 3 As shown, the regulating unit no longer drives the filter, but includes a pipe 71 and a switching valve 72. During the ionization stage, the switching valve 72 is closed, and the carrier gas must pass through the filter unit 61. During the cooling stage, the switching valve 72 is open, and the carrier gas does not pass through the filter unit 61.

[0077] 2. The gas outlet includes only the first outlet 321, and the inner wall of the second side 13 is in the shape of an inverted frustum.

[0078] m1 = 6.25 × 10 -5kg / s, A=0.076, m2=0.0102 kg / s, threshold=73.8 Pa.

[0079] The ionization method of the embodiment of the application, i.e. the working process of the ionization device of the embodiment, is as follows:

[0080] The ionization stage: the sample is ionized by the ion source 21, and a spray is formed at the outlet of the ion source 21;

[0081] The switch valve 72 is closed, the carrier gas enters the housing 11 from the plurality of gas inlets 31 at the first side 12 of the housing, then passes through the filter unit 61, carries the sheath gas and the auxiliary gas discharged from the outlet of the ion source 21, and is discharged from the gas outlet 32 at the second side 13; the second side 13 and the first side 12 are oppositely arranged;

[0082] The cooling stage: the ion source 21 is closed, the switch valve 72 is opened, the carrier gas enters the housing 11 from the plurality of gas inlets 31, the carrier gas flows to the lower side of the filter unit 61, i.e. does not pass through the filter unit 61, carries the gas in the housing 11, and is discharged from the gas outlet 32;

[0083] In the above stages, the pressure sensing module 51 obtains the gas pressure in the housing 11 and the pressure difference ΔP at the gas outlet 32;

[0084] The judging module judges whether the pressure difference is greater than a threshold value, and outputs the result to the control module; the threshold value is C1(m1+m2) 2 C2(m1+m2)=73.8 Pa;

[0085] If the judgment result is yes, the control module closes the negative pressure generating unit 41; in the embodiment, ΔP=573.6 Pa, and the negative pressure generating unit 41 is closed; simulation results show that the carrier gas can effectively discharge the solvent particles, and prevent the solvent particles from remaining in the housing;

[0086] If the judgment result is no, the control module opens the negative pressure generating unit 41.

Claims

1. An ionization device, comprising a housing and an electrospray ionization source, wherein the electrospray ionization source is disposed on the housing; characterized in that, The ionization device further includes: Gas inlets, multiple gas inlets surround the ion source, and are disposed on the first side of the housing together with the electrospray ion source; A filter unit is disposed within the housing and positioned between a first side and a second side of the housing that are opposite to each other. The outlet of the ion source is located between the filter unit and the gas outlet. An adjustment unit is used to directly connect the spaces on both sides of the filter unit or to connect them through the filter unit, and includes a drive module for driving the filter unit to rotate around a rotating shaft. A gas outlet is provided on the second side of the housing; A negative pressure generating unit, wherein the negative pressure generating unit is connected to the gas outlet; The control unit includes a pressure sensing module, which obtains the gas pressure inside the housing and the pressure difference ΔP at the gas outlet. The judgment module is used to determine whether the pressure difference is greater than a threshold, and the output result is sent to the control module. The control module is used to turn off the negative pressure generating unit when the judgment result is yes, and turn on the negative pressure generating unit when the result is no.

2. The ionization device according to claim 1, characterized in that, The threshold is: C1(m1+m2) 2 -C2(m1+m2), where m2 is the flow rate through the gas inlet, m1 is the flow rate of the gas discharged from the ion source outlet, and C1 and C2 are coefficients.

3. The ionization device according to claim 1, characterized in that, The flow rate through the gas inlet satisfies m2: m2 = C3A 2 -C4A+C5m1+C6, where A is the ratio of the cross-sectional area of ​​the gas outlet to the area of ​​the second side, and C3, C4, C5, and C6 are coefficients.

4. The ionization device according to claim 1, characterized in that, The gas outlet includes a first outlet, and the central axis of the first outlet and the central axis of the outlet of the ion source are in the same plane.

5. The ionization device according to claim 4, characterized in that, The gas outlet further includes other outlets surrounding the first outlet.

6. The ionization device according to claim 1, characterized in that, The adjustment unit includes: The pipeline and the switching valve are provided. The input end of the pipeline connects to the internal space of the housing between the filter unit and the gas inlet, and the output end connects to the internal space of the housing between the filter unit and the gas outlet. The switching valve is installed on the pipeline.

7. An ionization method using the ionization apparatus of claim 1, wherein the ionization method is as follows: During the ionization stage, the sample is ionized by the ion source, and a spray is formed at the outlet of the ion source, which is located inside the housing between the filter unit and the second side of the housing. The carrier gas enters the housing through multiple gas inlets on the first side of the housing, then passes through the filter unit, carrying the sheath gas and auxiliary gas discharged from the outlet of the ion source, and is discharged from the gas outlet on the second side; the second side and the first side are arranged opposite to each other; During the cooling phase, the ion source is turned off, and the carrier gas enters the housing from the multiple gas inlets. Without passing through the filter unit, it carries the gas inside the housing and exits from the gas outlet.

8. The ionization method according to claim 7, characterized in that, The pressure sensing module obtains the gas pressure inside the housing and the pressure difference ΔP at the gas outlet; The judgment module determines whether the pressure difference is greater than a threshold, and sends the result to the control module; the threshold is C1(m1+m2). 2 -C2(m1+m2), where m2 is the flow rate through the gas inlet, m1 is the flow rate of the gas discharged from the ion source outlet, and C1 and C2 are coefficients. The control module shuts down the negative pressure generating unit when the judgment result is yes, and turns on the negative pressure generating unit when the result is no. The negative pressure generating unit is connected to the gas outlet.

9. The ionization method according to claim 7, characterized in that, The flow rate through the gas inlet satisfies m2: m2 = C3A 2 -C4A+C5m1+C6, where A is the ratio of the cross-sectional area of ​​the gas outlet to the area of ​​the second side, and C3, C4, C5, and C6 are coefficients.

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