WO2013055081A1

WO2013055081A1 - Ion regulator for mass spectrometer, mass spectrometer comprising the same and method of regulating ion for mass spectrometer

Info

Publication number: WO2013055081A1
Application number: PCT/KR2012/008178
Authority: WO
Inventors: Myoung Choul Choi; Sang Hwan Choi; Se Gyu Lee; Jeong Min Lee; Yang Sun Kim
Original assignee: Korea Basic Science Institute; Asta Co., Ltd.
Priority date: 2011-10-13
Filing date: 2012-10-10
Publication date: 2013-04-18
Also published as: KR20130039857A; KR101287441B1

Abstract

An ion regulator for a mass spectrometer may include: a first extraction lens having a first hole through which ions can pass; and a second extraction lens electrically isolated from the first extraction lens and having a second hole which is aligned with the first hole so that the ions passing through the first hole can pass therethrough. The surface of the first hole may be inclined with respect to the moving direction of the ions. Use of the ion regulator will simplify the overall structure of a mass spectrometer and control parameters therefor, and will allow the development of a reliable and efficient compact mass spectrometer.

Description

ION REGULATOR FOR MASS SPECTROMETER, MASS SPECTROMETER COMPRISING THE SAME AND METHOD OF REGULATING ION FOR MASS SPECTROMETER

Embodiments relate to an ion regulator with simplified structure of a lens for focusing ions and a lens for controlling deflection of ions used in a mass spectrometer, e.g., a time-of-flight mass spectrometer, a mass spectrometer including the same, and a method of regulating ions for a mass spectrometer.

A time-of-flight (TOF) mass spectrometer (MS) is an apparatus for elucidating molecular structure by measuring the mass of molecular ions and fragment ions, and has become a standard for high-resolution broadband mass spectrometry. The TOF MS may have an ionization source based on matrix-assisted laser desorption ionization (MALDI), electrospray ionization (ESI), or the like. The TOF MS can measure the mass of ions by accelerating the ions generated by the ionization source and measuring the time of flight of the ions. For example, US Patent No. 7,034,288 titled "Time-of-flight mass spectrometer" discloses a conventional TOF MS.

FIG. 1 schematically shows the configuration of a conventional TOF MS.

Referring to FIG. 1, a sample plate 2 may be positioned on a stage 1, and a sample 3 may be placed on the sample plate 2. When a laser is irradiated to the sample 3, ions 4 may be generated from the sample 3. The generated ions 4 are accelerated by an acceleration voltage applied to

extraction lenses

11, 12 and move toward a detector 15. The detector 15 determines the mass of the ions 4 by measuring the time during which the ions 4 fly through a zone with a predetermined length having a zero (0) potential difference after passing through the

extraction lenses

11, 12.

In order to prevent the ions 4 from diffusing, an einzel lens 13 consisting of three electrodes aligned in series is used to focus the ions to the center. And, in order to correct misalignment that may occur during installation of the apparatus, a deflection lens 14 is used to adjust the motion of the ions toward the detector 15. The einzel lens 13 and the deflection lens 14 are respectively connected to a power circuit for voltage control. Control of the performance of detection signals and improvement of the ion signals are achieved by adjusting the voltage applied thereto.

However, an increased number of the

lenses

13, 14 for regulating the focusing and deflection of the ions results in increased burden of controlling the voltage applied to the

lenses

13, 14 as well as increased complexity in the operation of the mass spectrometer and increased number of power supplies to be used. As a result, the overall apparatus size increases and use of the apparatus becomes complicated.

According to an aspect, the present disclosure is directed to providing an ion regulator for a mass spectrometer capable of regulating focusing and deflection of ions without additional electrodes or power supplies and thus capable of minimizing the number of electrodes for ion regulation and power supplies, a mass spectrometer including the same, and a method of regulating ions for a mass spectrometer.

An ion regulator for a mass spectrometer according to an exemplary embodiment may include: a first extraction lens having a first hole through which ions can pass; and a second extraction lens electrically isolated from the first extraction lens and having a second hole which is aligned with the first hole so that the ions passing through the first hole can pass therethrough. The surface of the first hole may be inclined with respect to the moving direction of the ions.

A mass spectrometer according to an exemplary embodiment may include: an ion regulator comprising a first extraction lens having a first hole through which ions generated from a sample can pass, and a second extraction lens having a second hole which is aligned with the first hole so that the ions passing through the first hole can pass therethrough; and a detector detecting the ions emitted from the ion regulator through the second hole. The surface of the first hole may be inclined with respect to the moving direction of the ions.

A method of regulating ions for a mass spectrometer according to an exemplary embodiment may include: providing a first extraction lens having a first hole and a second extraction lens having a second hole which is aligned with the first hole, wherein the surface of the first hole is inclined with respect to a line connecting the center of the first hole and the center of the second hole; applying a voltage between the first extraction lens and the second extraction lens; and passing ions through the first hole and the second hole.

An ion regulator for a mass spectrometer, a mass spectrometer comprising the same and a method of regulating ions for a mass spectrometer according an aspect of to the present disclosure allows the regulation of ions in a mass spectrometer such as a time-of-flight mass spectrometer in a mechanical way using an electrode for accelerating ions. Accordingly, the number of electrodes for regulation of ions and power supplies needed therefor can be reduced and the parameters for ion regulation can be minimized.

As a result, the overall size of the mass spectrometer can be reduced and the operation of the mass spectrometer becomes simple and user-friendly. Also, the miniaturization of the mass spectrometer will make it possible to develop a portable apparatus. And, since the mass spectrometer can be operated with a decreased number of power supplies, instabilities such as vulnerability to heat, moisture, etc. as well as limited operation life can be minimized and a more reliable mass spectrometer can be realized.

The above and other objects, features and advantages of the present disclosure will become apparent from the following description of certain exemplary embodiments given in conjunction with the accompanying drawings, in which:

FIG. 1 schematically shows the configuration of a conventional time-of-flight mass spectrometer;

FIG. 2 schematically shows a mass spectrometer having an ion regulator according to an exemplary embodiment;

FIGS. 3a and 3b illustrate a process of adjusting the moving direction of ions using an ion regulator according to an exemplary embodiment; and

FIG. 4 shows a simulation result for the change of the moving direction of ions using an ion regulator according to an exemplary embodiment.

The advantages, features and aspects of the present disclosure will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter. The present disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings.

FIG. 2 schematically shows a mass spectrometer having an ion regulator according to an exemplary embodiment.

Referring to FIG. 2, an ion regulator of a mass spectrometer may comprise a first extraction lens 21 and a second extraction lens 22. The first extraction lens 21 may have a first hole 210 through which ions can pass. Also, the second extraction lens 22 may have a second hole 220 through which ions can pass. The first hole 210 and the second hole 220 may be aligned at least in part such that ions can sequentially pass through the first hole 210 and the second hole 220. A voltage may be applied to the first extraction lens 21 and the second extraction lens 22, respectively. For this purpose, the first extraction lens 21 and the second extraction lens 22 may be made of, at least in part, a conducting material.

For example, each of the first extraction lens 21 and the second extraction lens 22 may be in the form of a disk having a

circular hole

210, 220. However, this is only exemplary, and the first extraction lens 21 and the second extraction lens 22 and the first hole 210 and the second hole 220 may have different shapes adequate for the ions to pass therethrough. In addition, the first extraction lens 21 and the second extraction lens 22 are not necessarily physically single devices. For instance, the first extraction lens 21 and the second extraction lens 22 may consist of electrodes spaced apart from each other. In this case, the gap between the electrodes through which ions can pass may correspond to the first hole 210 and second hole 220.

When a sample 3 is placed on a sample plate 2 positioned on a stage 1 and a laser is irradiated to the sample 3, ions 4 may be generated from the sample 3. A voltage may be applied to the sample plate 2. The generated ions 4 may be accelerated toward the first extraction lens 21 by the voltage difference between the sample plate 2 and the first extraction lens 21 and may be incident to the hole 210 of the first extraction lens 21. For example, a voltage of about 20 kV may be applied to the sample plate 2, and a voltage of about 19 kV may be applied to the first extraction lens 21. However, this is only exemplary, and the magnitude of the voltage applied to each portion of the mass spectrometer is not limited to the exemplary description of this disclosure.

The ions 4 passing through the first hole 210 may be accelerated toward the second extraction lens 22 by the voltage difference between the first extraction lens 21 and the second extraction lens 22. For example, a voltage of about 19 kV may be applied to the first extraction lens 21, and a voltage of 0 V may be applied to the second extraction lens 22. The accelerated ions pass through the second hole 220 of the second extraction lens 22 and are emitted from the ion regulator toward a detector 25. Like the second extraction lens 22, a voltage of 0 V may be applied to the detector 25. The detector 25 may determine the mass of the ions 4 by measuring the time during which the ions 4 fly through a zone with a voltage difference of 0 after passing through the second extraction lens 22 until they reach the detector 25.

In the above-described ion regulator, the surface of the first hole 210 may be inclined with respect to the moving direction of the ions. That is to say, the surface of the first hole 210 may have an angle θ larger than 0° and smaller than 90° with respect to a line connecting the center of the first hole 210 and the center of the second hole 220. The inclination of the surface of the first hole 210 may be determined such that the area of the portion where the ions are incident to the first hole 210 is smaller than the area of the portion where the ions are emitted from the first hole 210. As a result, the ions passing through the first hole 210 may be focused by an electric field formed on the surface of the first hole 210. That is to say, the ions passing through the first hole 210 may be focused toward the center of the moving direction of the ions, i.e., in the direction of an extension line from the center of the first hole 210.

In the above-described ion regulator, instead of using an einzel lens consisting of several electrodes for focusing of ions as in the conventional technology, an inclined hole is formed on the extraction lens, which is an essential component of the mass spectrometer, to focus the ions. Accordingly, the number of the electrodes for focusing ions and power supplies therefor can be reduced and miniaturization and simplification of the apparatus can be achieved. In another exemplary embodiment, the ion regulator may be configured not only to focus the ions but also to regulate the moving direction of the ions as will be describe in detail.

FIGS. 3a and 3b illustrate a process of adjusting the moving direction of ions using an ion regulator according to an exemplary embodiment. When describing the embodiment illustrated in FIGS. 3a and 3b, detailed description about the matters that can be easily understood by those skilled in the art from the foregoing description referring to FIG. 2 will be omitted to avoid unnecessary redundancy.

Referring to FIG. 3a, an ion regulator according to an embodiment may comprise a support 26 contacting with a first extraction lens 21. The support 26 serves to correct misalignment that may occur during the installation of the mass spectrometer. The support 26 may be made of a conducting material such as metal or an insulating material, but without being limited to a particular material. By applying a pressure to the support 26, the direction of the first extraction lens 21 may be mechanically adjusted and, as a result, the direction of acceleration of ions can be controlled. Accordingly, the direction of acceleration of ions can be regulated easily without having to use a deflection lens used in the existing mass spectrometer.

In an exemplary embodiment, the support 26 may be in the form of a disk having a circular hole 260. However, this is only exemplary, and the support 26 and the hole 260 may have different shapes adequate to pass the ions. The hole 260 of the support 26 and a first hole 210 of the first extraction lens 21 may be aligned at least in part such that ions 4 generated from a sample 3 can pass through the first the hole 260 of the support 26 and through the first hole 210.

In an exemplary embodiment, the support 26 may be made of a flexible material. And, in an exemplary embodiment, a pressure may be applied to the support 26 using one or more pressure control means. For example, the support 26 may be contacted with a first pressure controller 27 and a second pressure controller 28. The first pressure controller 27 and the second pressure controller 28 may be in the form of a rod adequate to apply a pressure to the support 26, although not being limited thereto. And, the first pressure controller 27 and the second pressure controller 28 may be made of an insulating material.

The direction of the first extraction lens 21 may be adjusted as desired by means of mechanical pressing of the support 26 using the first pressure controller 27 and/or the second pressure controller 28. For this purpose, the first pressure controller 27 and the second pressure controller 28 may be positioned at either end of the hole 260 of the support 26 with the hole 260 therebetween. By applying a pressure of different direction and/or magnitude to the first pressure controller 27 and the second pressure controller 28, the direction of the first extraction lens 21 may be adjusted as desired.

For example, referring to FIG. 3b, the support 26 may be declined rightward in the figure by pulling the first pressure controller 27 while pushing the second pressure controller 28. In case of a time-of-flight mass spectrometer, the distance from an electrode for accelerating ions to a detector is relatively very large as compared to the size of the electrode. Accordingly, even when the support 26 is tilted by 1°, the portion where the ions reach the detector may be changed greatly. Thus, since it is not necessary to excessively tilt the support 26, nonlinear properties caused by the distortion of the support 26 may be minimized.

In an exemplary embodiment, the first extraction lens 21 may be at least in part coupled to a second extraction lens 22, such that the direction of the second extraction lens 22 can be adjusted by adjusting the direction of the first extraction lens 21 using the support 26. However, this is only exemplary. In another embodiment, the direction of the first extraction lens 21 may be adjusted independently of the direction of the second extraction lens 22.

In the foregoing embodiment described referring to FIGS. 3a and 3b, two pressure controllers, i.e. the first pressure controller 27 and the second pressure controller 28, were used as a means to apply pressure to the support 26. However, this is only exemplary, and more or less pressure controllers may be used. For example, in an exemplary embodiment, three or more pressure controllers aligned to be spaced apart from each other may be used to apply a pressure to the support 26, in order to regulate the moving direction of ions in vertical and horizontal axes in a plane where the ions reach.

The three paths of

ions

400, 410, 420 shown in FIG. 4 are the paths of ions when the tilt angle of the first extraction lens is 0°, about 1° and about 2°, respectively. As shown in the figure, the position where the ions reach change relatively greatly even when the tilt angle of the lens is only 1°.

While the present disclosure has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the disclosure as defined in the following claims.

Claims

An ion regulator for a mass spectrometer, comprising:

a first extraction lens having a first hole through which ions can pass; and

a second extraction lens electrically isolated from the first extraction lens and having a second hole which is aligned with the first hole so that the ions passing through the first hole can pass therethrough,

wherein the surface of the first hole is inclined with respect to the moving direction of the ions.
The ion regulator for a mass spectrometer according to claim 1, further comprising a support supporting the first extraction lens, wherein the support is disposed such that the direction of the first extraction lens can be changed by a pressure applied to the support.
The ion regulator for a mass spectrometer according to claim 2, wherein the support is made of a flexible material.
The ion regulator for a mass spectrometer according to claim 2, further comprising at least one pressure controller contacting with the support and controlling the pressure applied to the support.
The ion regulator for a mass spectrometer according to claim 4, wherein the at least one pressure controller comprises at least three pressure controllers aligned to be spaced apart from each other.
The ion regulator for a mass spectrometer according to claim 4, wherein the pressure controller is in the form of a rod made of an insulating material.
A mass spectrometer comprising:

an ion regulator comprising a first extraction lens having a first hole through which ions generated from a sample can pass, and a second extraction lens having a second hole which is aligned with the first hole so that the ions passing through the first hole can pass therethrough; and

a detector detecting the ions emitted from the ion regulator through the second hole,

wherein the surface of the first hole is inclined with respect to the moving direction of the ions.
The mass spectrometer according to claim 7, wherein the ions emitted through the second hole are directly incident to the detector.
The mass spectrometer according to claim 7, wherein the ion regulator further comprises a support supporting the first extraction lens, wherein the support is disposed such that the direction of the first extraction lens can be changed by a pressure applied to the support.
The mass spectrometer according to claim 9, wherein the ion regulator further comprises at least one pressure controller contacting with the support and controlling the pressure applied to the support.
A method of regulating ions for a mass spectrometer, comprising:

providing a first extraction lens having a first hole and a second extraction lens having a second hole which is aligned with the first hole, wherein the surface of the first hole is inclined with respect to a line connecting the center of the first hole and the center of the second hole;

applying a voltage between the first extraction lens and the second extraction lens; and

passing ions through the first hole and the second hole.
The method of regulating ions for a mass spectrometer according to claim 11, wherein the passing the ions through the first hole and the second hole comprises focusing the ions passing through the first hole toward the center of the moving direction of the ions by means of an electric field formed on the surface of the first hole.
The method of regulating ions for a mass spectrometer according to claim 11, further comprising changing the direction of the first extraction lens by adjusting a pressure applied to a support contacting the first extraction lens.