阅读说明：本技术 飞行时间质谱仪离子源和飞行时间质谱仪 (Time-of-flight mass spectrometer ion source and time-of-flight mass spectrometer ) 是由 喻佳俊 林利泉 黄武海 黄凯彬 吕德辉 吕金诺 于 2018-06-28 设计创作，主要内容包括：本申请涉及一种飞行时间质谱仪离子源和飞行时间质谱仪。所述飞行时间质谱仪离子源包括加速电场产生装置,加速电场产生装置包括第一电极和第二电极,第一电极用于加载指数脉冲电压,第二电极用于加载方形脉冲电压,指数脉冲电压和方形脉冲电压的频率相同,加速电场产生装置用于在指数脉冲电压和方形脉冲电压下,对离子进行加速,使得同质量数的离子同时到达检测器。采用上述飞行时间质谱仪离子源能够将相同频率的指数脉冲电压和方形脉冲电压分别施加在加速电场产生装置的第一电极和第二电极,使得加速电场产生装置上可以加载易于调谐的加速电压,增强加速电压稳定性,以便于对离子进行精准和稳定的加速,提高飞行时间质谱仪的分辨率。(The present application relates to a time-of-flight mass spectrometer ion source and a time-of-flight mass spectrometer. The ion source of the time-of-flight mass spectrometer comprises an accelerating electric field generating device, wherein the accelerating electric field generating device comprises a first electrode and a second electrode, the first electrode is used for loading exponential pulse voltage, the second electrode is used for loading square pulse voltage, the frequency of the exponential pulse voltage is the same as that of the square pulse voltage, and the accelerating electric field generating device is used for accelerating ions under the exponential pulse voltage and the square pulse voltage so that the ions with the same mass number reach a detector at the same time. By adopting the ion source of the time-of-flight mass spectrometer, the exponential pulse voltage and the square pulse voltage with the same frequency can be applied to the first electrode and the second electrode of the accelerating electric field generating device respectively, so that the accelerating electric field generating device can be loaded with the accelerating voltage which is easy to tune, the stability of the accelerating voltage is enhanced, the ions can be accelerated accurately and stably, and the resolution of the time-of-flight mass spectrometer is improved.)

1. An ion source of a time-of-flight mass spectrometer, comprising accelerating electric field generating means;

the accelerating electric field generating device comprises a first electrode and a second electrode;

the first electrode is used for loading exponential pulse voltage, the second electrode is used for loading square pulse voltage, the frequency of the exponential pulse voltage is the same as that of the square pulse voltage, and the accelerating electric field generating device is used for accelerating ions under the exponential pulse voltage and the square pulse voltage, so that the ions with the same mass number reach the detector at the same time.

2. The time-of-flight mass spectrometer ion source of claim 1, wherein the pulse start position of the exponential pulse voltage is temporally co-located with the pulse start position of the square wave pulse voltage.

3. The time-of-flight mass spectrometer ion source of claim 2, wherein the pulse width of the exponential pulse voltage is equal to the pulse width of the square pulse voltage.

4. The time-of-flight mass spectrometer ion source of claim 2, wherein the first electrode comprises a sample target from which positive ions are generated by ionization;

one exponential pulse of the exponential pulse voltage after the laser pulse irradiates the sample target and the delay time is

one square wave pulse of the square wave pulse voltage after the laser pulse irradiates the sample target and the delay time is

5. The time-of-flight mass spectrometer ion source of claim 2, wherein the first electrode comprises a sample target from which negative ions are generated by ionization;

one exponential pulse of the exponential pulse voltage after the laser pulse irradiates the sample target and the delay time is

one square wave pulse of the square wave pulse voltage after the laser pulse irradiates the sample target and the delay time is

6. The time-of-flight mass spectrometer ion source of claim 1, further comprising an accelerating electric field power supply circuit;

the accelerating electric field power supply circuit comprises an output interface and an input interface;

the output interface comprises an index pulse voltage interface and a square pulse voltage interface, the index pulse voltage interface is connected with the first electrode, the square pulse voltage interface is connected with the second electrode, the index pulse voltage interface is used for inputting the index pulse voltage to the first electrode, and the square pulse voltage interface is used for inputting the square pulse voltage to the second electrode;

the input interface comprises a high-voltage interface, an index pulse signal interface and a square wave pulse signal interface, wherein the high-voltage interface is used for being connected with a high-voltage power supply, the index pulse signal interface is used for being connected with an index pulse signal, and the square wave pulse signal interface is used for being connected with a square wave pulse signal.

7. The time-of-flight mass spectrometer ion source of claim 6, wherein the accelerating electric field power supply circuit comprises a first resistor, a first capacitor, a second resistor, and a second capacitor;

the high-voltage power supply interface, the first resistor, the first capacitor and the index pulse signal interface are connected in series, and the index pulse voltage interface is a connection point between the first resistor and the first capacitor;

the high-voltage power supply interface, the second resistor, the second capacitor and the square wave pulse signal interface are connected in series, and the square pulse voltage interface is a connection point between the second resistor and the second capacitor.

8. A time-of-flight mass spectrometer comprising a time-of-flight mass spectrometer ion source according to any of claims 1 to 7, wherein the time-of-flight mass spectrometer ion source is arranged to accelerate ions such that ions of the same mass number arrive at the detector simultaneously.

9. The time-of-flight mass spectrometer of claim 8, further comprising a drift tube, a high voltage power supply, a system controller, a mass analyzer, and the detector, the time-of-flight mass spectrometer ion source comprising the accelerating electric field generating device and an accelerating electric field power supply circuit, the accelerating electric field generating device comprising a first electrode and a second electrode;

the accelerating electric field power supply circuit is respectively connected with the first electrode and the second electrode, the system controller is respectively connected with the pulse laser, the accelerating electric field power supply circuit, the high-voltage power supply and the detector, and the mass analyzer is respectively connected with the detector and the system controller;

the drift tube is used for forming a field-free flight area;

the accelerating electric field generating device of the time-of-flight mass spectrometer ion source, the drift tube and the detector are sequentially arranged in space, and ions with the same mass number simultaneously arrive at the detector after passing through the field-free flight area;

the system controller is used for controlling the pulse laser to output pulse laser, inputting an index pulse signal and a square wave pulse signal to the accelerating electric field power supply circuit, and controlling the high-voltage power supply to input high-voltage to the accelerating electric field power supply circuit;

and the mass analyzer is used for acquiring a mass spectrogram according to the detection signal of the detector and the measurement parameters of the system controller.

10. The time-of-flight mass spectrometer of claim 9, further comprising a pulsed laser, the first electrode comprising a sample target, the pulsed laser for outputting pulsed laser light by which the sample target is irradiated and the ions are generated in the accelerating electric field generating means.

Technical Field

The application relates to the technical field of time-of-flight mass spectrometers, in particular to a time-of-flight mass spectrometer ion source and a time-of-flight mass spectrometer.

Background

The time-of-flight mass spectrometer is a mass spectrometer which has simple structure, high sensitivity and high resolution, theoretically has no upper limit on analytical mass and is suitable for a pulse ion source, and the matrix-assisted laser desorption ionization time-of-flight mass spectrometer formed by combining the matrix-assisted laser desorption ionization source is gradually an important means for analyzing biomacromolecules such as protein, polypeptide, nucleic acid and the like.

The delay extraction technology is a method capable of improving the resolution of a mass spectrum, and is characterized in that ions generated by laser ionization are not accelerated immediately, but are allowed to fly freely for about hundreds of nanoseconds according to the initial speed of the ions in a relatively electric field-free environment, and then the ions are accelerated and extracted by utilizing a pulse technology. The core principle of this technique is to increase the initial positional dispersion of ion generation and to compensate the initial spatial dispersion of ions with the positional dispersion. The delay extraction technology can greatly improve the mass resolution of the matrix-assisted laser desorption ionization time-of-flight mass spectrometer. However, since the required delay time is inconsistent for ions of different mass numbers, the conventional delayed extraction technique has an ion discrimination effect, and usually only produces a good resolution enhancement effect for ions in a specific range.

Through the similar exponential waveform pulse of the pulse focusing technology, ions with the same mass number can be accelerated to reach a detector at the same time, and the focusing of mass spectrogram spectral lines is realized. However, under the pulse focusing technology, the generation mode of the quasi-exponential waveform pulse is complex, tuning is difficult, focusing performance is not good, and the resolution of the time-of-flight mass spectrometer is low.

Disclosure of Invention

In view of the above, it is necessary to provide a time-of-flight mass spectrometer ion source and a time-of-flight mass spectrometer in view of the low resolution of the time-of-flight mass spectrometer.

An ion source of a time-of-flight mass spectrometer comprises an accelerating electric field generating device;

the accelerating electric field generating device comprises a first electrode and a second electrode;

the first electrode is used for loading exponential pulse voltage, the second electrode is used for loading square pulse voltage, the frequency of the exponential pulse voltage is the same as that of the square pulse voltage, and the accelerating electric field generating device is used for accelerating ions under the exponential pulse voltage and the square pulse voltage, so that the ions with the same mass number reach the detector at the same time.

In one embodiment, the pulse start position of the exponential pulse voltage is temporally identical to the pulse start position of the square wave pulse voltage.

In one embodiment, the pulse width of the exponential pulse voltage is equal to the pulse width of the square pulse voltage.

In one embodiment, the first electrode includes a sample target, and the detection object is positive ions generated by ionization from the sample target;

one exponential pulse of the exponential pulse voltage after the laser pulse irradiates the sample target and the delay time is

Wherein, U_eIs an exponential pulse voltage, U₀To accelerate the voltage, U₁Is the amplitude of the exponential pulse voltage, tau is the delay time, t_w1Is the time constant of the exponential pulse voltage, U₀And U₁Is a positive number;

one square wave pulse of the square wave pulse voltage after the laser pulse irradiates the sample target and the delay time is

Wherein, U_rectIs a square wave pulse voltage, U₀To accelerate the voltage, U₂Is the amplitude of the square wave pulse voltage, and tau is the delayTime, t_w2Pulse width, U, of square-wave pulse voltage₀And U₂Is a positive number.

In one embodiment, the first electrode includes a sample target, and the detection object is negative ions generated by ionization from the sample target;

one exponential pulse of the exponential pulse voltage after the laser pulse irradiates the sample target and the delay time is

Wherein, U_eIs an exponential pulse voltage, U₀To accelerate the voltage, U₁Is the amplitude of the exponential pulse voltage, tau is the delay time, t_w1Is the time constant of the exponential pulse voltage, U₀And U₁Is a positive number;

one square wave pulse of the square wave pulse voltage after the laser pulse irradiates the sample target and the delay time is

Wherein, U_rectIs a square wave pulse voltage, U₀To accelerate the voltage, U₂Is the amplitude of the square wave pulse voltage, tau is the delay time, t_w2Pulse width, U, of square-wave pulse voltage₀And U₂Is a positive number.

In one embodiment, the time-of-flight mass spectrometer ion source further comprises an accelerating electric field power supply circuit;

the accelerating electric field power supply circuit comprises an output interface and an input interface;

the output interface comprises an index pulse voltage interface and a square pulse voltage interface, the index pulse voltage interface is connected with the first electrode, the square pulse voltage interface is connected with the second electrode, the index pulse voltage interface is used for inputting index pulse voltage to the first electrode, and the square pulse voltage interface is used for inputting square pulse voltage to the second electrode;

the input interface comprises a high-voltage interface, an index pulse signal interface and a square wave pulse signal interface, the high-voltage interface is used for being connected with a high-voltage power supply, the index pulse signal interface is used for being connected with an index pulse signal, and the square wave pulse signal interface is used for being connected with a square wave pulse signal.

In one embodiment, the accelerating electric field power supply circuit includes a first resistor, a first capacitor, a second resistor, and a second capacitor;

the high-voltage power supply interface, the first resistor, the first capacitor and the index pulse signal interface are connected in series, and the index pulse voltage interface is a connection point between the first resistor and the first capacitor;

the high-voltage power supply interface, the second resistor, the second capacitor and the square wave pulse signal interface are connected in series, and the square pulse voltage interface is a connection point between the second resistor and the second capacitor.

A time-of-flight mass spectrometer comprising a time-of-flight mass spectrometer ion source, wherein the time-of-flight mass spectrometer ion source is arranged to accelerate ions such that ions of the same mass number arrive at a detector simultaneously.

In one embodiment, the time-of-flight mass spectrometer further comprises a drift tube, a high voltage power supply, a system controller, a mass analyzer and a detector, the ion source of the time-of-flight mass spectrometer comprises an accelerating electric field generating device and an accelerating electric field power supply circuit, and the accelerating electric field generating device comprises a first electrode and a second electrode;

the system controller is respectively connected with the pulse laser, the accelerating electric field power circuit, the high-voltage power supply and the detector, and the mass analyzer is respectively connected with the detector and the system controller;

the drift tube is used for forming a field-free flight area;

the accelerating electric field generating device, the drift tube and the detector of the ion source of the time-of-flight mass spectrometer are sequentially arranged in space, and ions with the same mass number simultaneously reach the detector after passing through the field-free flight area;

the system controller is used for controlling the pulse laser to output pulse laser, inputting an index pulse signal and a square wave pulse signal to the accelerating electric field power circuit, and controlling the high-voltage power supply to input high-voltage to the accelerating electric field power circuit;

the mass analyzer is used for acquiring a mass spectrogram according to a detection signal of the detector and a measurement parameter of the system controller.

In one embodiment, the time-of-flight mass spectrometer further comprises a pulsed laser, the first electrode comprising a sample target, the pulsed laser for outputting pulsed laser light, irradiating the sample target with the pulsed laser light and generating ions in the accelerating electric field generating means.

Above-mentioned time of flight mass spectrometer ion source and time of flight mass spectrometer, the exponential pulse voltage and the square pulse voltage of same frequency are applyed respectively at the first electrode and the second electrode of accelerating the electric field generating device for can load the accelerating voltage of easily tuning on the accelerating electric field generating device, strengthen accelerating voltage stability, reduce because the unstable interference to the ion of accelerating voltage, so that carry out accurate and stable acceleration to the ion, improve time of flight mass spectrometer's resolution ratio.

Drawings

FIG. 1 is a schematic diagram of the ion source of a time-of-flight mass spectrometer in one embodiment;

FIG. 2 is a timing diagram of the pulses of the accelerating electric field generating device according to one embodiment;

FIG. 3(a) is a timing diagram of positive ion detection pulses in one embodiment;

FIG. 3(b) is a timing diagram of the pulse for detecting negative ions in one embodiment;

FIG. 4 is a schematic diagram of an accelerating electric field power supply circuit according to an embodiment;

FIG. 5 is a schematic diagram of an accelerating electric field power circuit according to another embodiment;

FIG. 6 is a schematic diagram of the structure of a time-of-flight mass spectrometer in one embodiment;

FIG. 7 is a schematic diagram of a time-of-flight mass spectrometer in a further embodiment;

FIG. 8 is a schematic diagram of a pulsed laser according to one embodiment;

FIG. 9 is a schematic diagram of another embodiment of a time-of-flight mass spectrometer;

FIG. 10 is a timing diagram of pulses for a time-of-flight mass spectrometer in another embodiment;

FIG. 11 is a schematic diagram of the pulsing of positive ion detection and negative ion detection in another embodiment;

FIG. 12 is a graph of simulated contrast resolution in another embodiment;

FIG. 13 is a mixed polypeptide mass spectrum of another embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In one embodiment, as shown in fig. 1, fig. 1 is a schematic structural diagram of an ion source of a time-of-flight mass spectrometer in one embodiment, in this embodiment, an ion source of a time-of-flight mass spectrometer is provided, which includes an accelerating electric field generating device; the accelerating electric field generating device comprises a first electrode 10 and a second electrode 20;

the first electrode 10 is used for loading exponential pulse voltage, the second electrode 20 is used for loading square pulse voltage, wherein the frequency of the exponential pulse voltage is the same as that of the square pulse voltage, and the accelerating electric field generating device is used for accelerating ions under the exponential pulse voltage and the square pulse voltage, so that the ions with the same mass number reach the detector at the same time.

Above-mentioned time of flight mass spectrometer ion source, the first electrode 10 and the second electrode 20 at the electric field generating device are accelerated to exponential pulse voltage and the square pulse voltage of same frequency are applyed respectively for can load the accelerating voltage of easily tuning on the electric field generating device with higher speed, strengthen accelerating voltage stability, reduce because the unstable interference to the ion of accelerating voltage, so that carry out accurate and stable acceleration to the ion, the pulse voltage frequency is more stable, can reduce time of flight's error, time of flight mass spectrometer's resolution ratio is improved.

The method comprises the steps of applying exponential pulse voltage and square pulse voltage with the same frequency to a first electrode 10 and a second electrode 20 of an accelerating electric field generating device respectively, wherein the pulse periods of the exponential pulse voltage and the square pulse voltage are the same, the exponential pulse voltage of one period and the square pulse voltage of one period are loaded on the accelerating electric field generating device, and an accelerating electric field is formed in the accelerating electric field generating device in the period to accelerate ions. And the frequency of the pulse voltage is stable, the accelerating electric field is stably formed in a period, the frequency of the accelerating electric field is also stable, the error of the flight time is reduced, the influence of unstable voltage on the resolution of the flight time mass spectrometer is greatly avoided, and the resolution of the flight time mass spectrometer is improved. As shown in the equation for the resolution of a time-of-flight mass spectrometer: and R is t/2 delta t, wherein the time of flight t is shown, delta t is a time of flight error, and the smaller the time of flight error is, the higher the resolution of the time of flight mass spectrometer is.

The sample target can be used for placing a sample, for example, the sample can be placed on the sample target by dropping a sample solution onto the sample target and drying, and the sample can be used for generating ions after being irradiated by laser. The sample target can be placed on the first electrode or the second electrode, i.e. an exponential pulse voltage can be applied to the sample target through the first electrode, and a square wave pulse voltage can also be applied to the sample target through the second electrode. And the intensity between the exponential pulse voltage of the first electrode and the square wave pulse voltage of the second electrode can be controlled to generate and provide an electric field capable of realizing acceleration for ions to be detected.

In one embodiment, the pulse start position of the exponential pulse voltage is temporally identical to the pulse start position of the square wave pulse voltage.

FIG. 2 is a timing diagram of the pulse of the accelerating electric field generator in an embodiment, as shown in FIG. 2, where the initial position of the exponential pulse voltage, t, is shown in FIG. 2₀And also the pulse start position of the square wave pulse voltage, in a minimum pulse period, the accelerating electric field generating device starts to form an accelerating electric field at the pulse start positions of the exponential pulse voltage and the square wave pulse voltage, so that the ions start to accelerate at the pulse start positions.

According to the ion source of the time-of-flight mass spectrometer, the pulse starting positions of the exponential pulse voltage and the square wave pulse voltage are the same in time domain, and ions can be accurately controlled to accelerate.

For example, the pulse start positions of the exponential pulse voltage and the square wave pulse voltage start at the same time, and the pulse widths of the exponential pulse voltage and the square wave pulse voltage may be the same or different; when the pulse width is the same, the duration time of the accelerating electric field is the same as the pulse width; when the pulse widths are different, the accelerating electric field lasts at least the time of the minimum pulse width.

In one embodiment, the pulse width of the exponential pulse voltage is equal to the pulse width of the square pulse voltage.

As shown in fig. 2, t in fig. 2_w2Is the pulse width of the exponential pulse voltage, t_w2And also the pulse width of the square pulse voltage, in a minimum pulse period, the pulse width of the exponential pulse voltage is equal to the pulse width of the square pulse voltage, and within the pulse width, an accelerating electric field is formed in the accelerating electric field generating device to accelerate the ions.

The ion source of the time-of-flight mass spectrometer can form an accelerating electric field in the accelerating electric field generating device within a fixed pulse width, keep the accelerating electric field to be generated periodically, keep the periodic duration, stabilize the frequency of the accelerating electric field and improve the resolution of the time-of-flight mass spectrometer.

In one embodiment, the first electrode 10 includes a sample target, and the detection object is positive ions generated by ionization from the sample target;

one exponential pulse of the exponential pulse voltage after the laser pulse irradiates the sample target and the delay time is

Wherein, U_eIs an exponential pulse voltage, U₀To accelerate the voltage, U₁Is the amplitude of the exponential pulse voltage, tau is the delay time, t_w1Is the time constant of the exponential pulse voltage, U₀And U₁Is a positive number;

a square wave pulse of the square wave pulse voltage after the laser pulse irradiates the sample target and the delay time is passedIs composed of

Wherein, U_rectIs a square wave pulse voltage, U₀To accelerate the voltage, U₂Is the amplitude of the square wave pulse voltage, tau is the delay time, t_w2Pulse width, U, of square-wave pulse voltage₀And U₂Is a positive number.

The exponential pulse voltage and the convenient pulse voltage are shown in fig. 3(a), and fig. 3(a) is a pulse timing diagram of positive ion detection according to an embodiment.

The ion source of the time-of-flight mass spectrometer can provide a proper, stable and accurate accelerating electric field for positive ions, and improves the resolution of the time-of-flight mass spectrometer for mass spectrometry of the positive ions.

In one embodiment, the first electrode 10 includes a sample target, and the detection object is negative ions generated by ionization from the sample target;

one exponential pulse of the exponential pulse voltage after the laser pulse irradiates the sample target and the delay time isWherein, U_eIs an exponential pulse voltage, U₀To accelerate the voltage, U₁Is the amplitude of the exponential pulse voltage, tau is the delay time, t_w1Is the time constant of the exponential pulse voltage, U₀And U₁Is a positive number;

one square wave pulse of the square wave pulse voltage after the laser pulse irradiates the sample target and the delay time is

Wherein, U_rectIs a square wave pulse voltage, U₀To accelerate the voltage, U₂Is the amplitude of the square wave pulse voltage, tau is the delay time, t_w2Pulse width, U, of square-wave pulse voltage₀And U₂Is a positive number.

The exponential pulse voltage and the convenient pulse voltage are shown in fig. 3(b), and fig. 3(b) is a pulse timing diagram of positive ion detection according to an embodiment.

Above-mentioned time of flight mass spectrometer ion source can provide suitable, stable and accurate acceleration electric field for the anion, improves the time of flight mass spectrometer and carries out mass spectrometry's resolution ratio to the anion.

In one embodiment, as shown in fig. 4, fig. 4 is a schematic diagram of the structure of an accelerating electric field power supply circuit in one embodiment, the ion source of the time-of-flight mass spectrometer further comprises an accelerating electric field power supply circuit 30;

the accelerating electric field power circuit 30 includes an output interface and an input interface;

the output interface comprises an index pulse voltage interface and a square pulse voltage interface, the index pulse voltage interface is connected with the first electrode, the square pulse voltage interface is connected with the second electrode, the index pulse voltage interface is used for inputting index pulse voltage to the first electrode 10, and the square pulse voltage interface is used for inputting square pulse voltage to the second electrode 20;

the input interface comprises a high-voltage interface, an index pulse signal interface and a square wave pulse signal interface, the high-voltage interface is used for being connected with a high-voltage power supply, the index pulse signal interface is used for being connected with an index pulse signal, and the square wave pulse signal interface is used for being connected with a square wave pulse signal.

Above-mentioned time of flight mass spectrometer ion source acquires index impulse voltage and square wave impulse voltage through accelerating electric field power supply circuit 30 for can load the simple and easily harmonious impulse voltage of wave form on the electric field generating device with higher speed, and finally load the easy harmonious acceleration voltage on accelerating electric field generating device, the stability of reinforcing acceleration voltage, reduce because the unstable interference to the ion of acceleration voltage, so that carry out accurate and stable acceleration to the ion, improve time of flight mass spectrometer's resolution ratio.

In one embodiment, as shown in fig. 5, fig. 5 is a schematic structural diagram of an accelerating electric field power circuit 30 in another embodiment, and the accelerating electric field power circuit 30 includes a first resistor 31, a first capacitor 32, a second resistor 33, and a second capacitor 34;

the high-voltage power supply interface, the first resistor 31 and the first capacitor 32 are connected in series with the exponential pulse signal interface, and the exponential pulse voltage interface is a connection point between the first resistor 31 and the first capacitor 32;

the high-voltage power supply interface, the second resistor 33 and the second capacitor 34 are connected in series with the square wave pulse signal interface, and the square pulse voltage interface is a connection point between the second resistor 33 and the second capacitor 34.

According to the time-of-flight mass spectrometer ion source, the index pulse signals and the square wave pulse signals can be respectively suspended on the high-voltage through the resistor and the capacitor, the high-voltage index pulse voltage and the high-voltage square wave pulse voltage are output, the index pulse voltage and the square wave pulse voltage with enough strength are provided through a simple circuit, an accelerating electric field with enough field strength can be provided, and the cost of the time-of-flight mass spectrometer ion source can be reduced.

In one embodiment, as shown in fig. 6, fig. 6 is a schematic structural diagram of an embodiment of a time-of-flight mass spectrometer, where the time-of-flight mass spectrometer includes a time-of-flight mass spectrometer ion source 210, and the time-of-flight mass spectrometer ion source 210 is configured to accelerate ions so that ions with the same mass number reach a detector at the same time.

In the time-of-flight mass spectrometer, the ion source 210 includes an accelerating electric field generating device, the accelerating electric field generating device includes a first electrode and a second electrode, the first electrode is used for loading an exponential pulse voltage, the second electrode is used for loading a square pulse voltage, wherein the frequency of the exponential pulse voltage is the same as that of the square pulse voltage, and the accelerating electric field generating device is used for accelerating ions under the exponential pulse voltage and the square pulse voltage, so that the ions with the same mass number reach the detector at the same time; the accelerating voltage which is easy to tune can be loaded on the accelerating electric field generating device, the stability of the accelerating voltage is enhanced, and the interference to ions due to instability of the accelerating voltage is reduced, so that the ions are accelerated accurately and stably, and the resolution ratio of the time-of-flight mass spectrometer is improved.

In one embodiment, as shown in fig. 7, fig. 7 is a schematic structural diagram of a time-of-flight mass spectrometer in yet another embodiment, the time-of-flight mass spectrometer further includes a drift tube 220, a high voltage power supply 230, a system controller 240, a mass analyzer 250, and a detector 260, the ion source 210 of the time-of-flight mass spectrometer includes an accelerating electric field generating device 211 and an accelerating electric field power supply circuit 212, the accelerating electric field generating device 211 includes a first electrode and a second electrode;

the accelerating electric field power circuit 212 is respectively connected with the first electrode and the second electrode, the system controller 240 is respectively connected with the pulse laser, the accelerating electric field power circuit 212, the high-voltage power supply 230 and the detector 260, and the mass analyzer 250 is respectively connected with the detector 260 and the system controller 240;

the drift tube 220 is used to form a field-free flight region;

the accelerating electric field generating device 211, the drift tube 220 and the detector 260 of the ion source 210 of the time-of-flight mass spectrometer are sequentially arranged in space, and ions with the same mass number simultaneously arrive at the detector 260 after the ions generated by the ion source 210 of the time-of-flight mass spectrometer pass through a field-free flight area;

the system controller 240 is configured to control the pulse laser to output pulse laser, input an exponential pulse signal and a square wave pulse signal to the accelerating electric field power supply circuit 212, and control the high-voltage power supply 230 to input high-voltage to the accelerating electric field power supply circuit 212;

the mass analyzer 250 is configured to acquire a mass spectrum according to the detection signal of the detector 260 and the measurement parameter of the system controller 240.

The system controller 240 controls the pulsed laser output from the pulsed laser to impinge on the sample target with a delay time to allow detected ions to ionize from the sample target and fly away from the sample target. The time-of-flight mass spectrometer ion source 210 comprises an accelerating electric field generating device 211, wherein the accelerating electric field generating device 211 comprises a first electrode and a second electrode, the first electrode is used for loading exponential pulse voltage, the second electrode is used for loading square pulse voltage, the frequency of the exponential pulse voltage and the frequency of the square pulse voltage are the same, and the accelerating electric field generating device 211 is used for accelerating ions under the exponential pulse voltage and the square pulse voltage, so that ions with the same mass number reach the detector 260 at the same time. After ions fly away from the sample target, an exponential pulse voltage and a square pulse voltage are loaded on the accelerating electric field generating device 211 to form an accelerating voltage, the accelerating voltage forms an accelerating electric field in the accelerating electric field generating device 211, the accelerating electric field accelerates the ions, the ions pass through a field-free flying area, and finally the ions with the same mass number reach the detector 260.

According to the time-of-flight mass spectrometer, through the connection of the time-of-flight mass spectrometer ion source 210, the drift tube 220, the high-voltage power supply 230, the system controller 240, the mass analyzer 250 and the detector 260, the accelerating voltage which is easy to tune can be loaded on the accelerating electric field generating device 211, the stability of the accelerating voltage is enhanced, the interference to ions due to instability of the accelerating voltage is reduced, so that the ions can be accelerated accurately and stably, and the resolution of the time-of-flight mass spectrometer is improved.

In one embodiment, as shown in fig. 8, fig. 8 is a schematic diagram of a structure of a pulsed laser in one embodiment, the time-of-flight mass spectrometer further includes a pulsed laser 270, the first electrode includes a sample target, and the pulsed laser 270 is configured to output pulsed laser light, irradiate the sample target with the pulsed laser light, and generate ions in the accelerating electric field generating device 211.

The time-of-flight mass spectrometer also includes a pulsed laser 270 that ionizes the ions so that ions of the same mass number subsequently arrive at the detector at the same time.

In another embodiment, as shown in fig. 9, fig. 9 is a schematic structural diagram of a time-of-flight mass spectrometer in another embodiment, where the time-of-flight mass spectrometer in this embodiment includes an accelerating electric field generating device, an accelerating electric field power supply circuit, a high voltage power supply, a drift tube, and a detector. The accelerating electric field generating device comprises a first electrode, a second electrode and a ground electrode, wherein the first electrode is a sample target, and the second electrode is an extraction pole piece. As shown in fig. 10, fig. 10 is a pulse timing chart of another embodiment of the time-of-flight mass spectrometer, the frequency of the exponential pulse voltage and the frequency of the square pulse voltage are the same, and the frequency of the exponential pulse voltage and the frequency of the square pulse voltage are both the same as the frequency of the pulsed laser, that is, the minimum pulse period is the same. Start of pulse of exponential pulse voltageSet t₀And the pulse starting position t of the square wave pulse voltage₀The positions are the same in the time domain, and the pulse width of the exponential pulse voltage is equal to that of the square pulse voltage. Taking the detection of positive ions as an example, the lowest amplitude voltage of the exponential pulse voltage is equal to the highest amplitude voltage of the square wave pulse voltage, so that an accelerating voltage, i.e., an exponential-like voltage, is loaded between the accelerating electric field generating devices, and an accelerating electric field is formed in the accelerating electric field generating devices. The pulse widths of the exponential pulse voltage and the square wave pulse voltage need to meet the requirement that all accelerated ions can be accelerated to fly to a field-free flight area. The index pulse signal and the high-voltage power supply output index pulse voltage through the accelerating electric field power supply circuit and output the index pulse voltage to the sample target, and the square wave pulse signal and the high-voltage output square wave pulse voltage through the accelerating electric field power supply circuit and output the square wave pulse voltage to the extraction pole piece. After a pulse of the pulse laser irradiates the sample target, after the delay time of tau, the ionized ions are dispersed at the initial position in the delay time of tau, namely, the time delay extraction is carried out, like the ions a and b with mass numbers, and the cut-off speed after the ionization is respectively V_aAnd V_bIn which V is_a>V_bThe time of delayed extraction of ions a and b in the period is t_dThe distances of delayed extraction of ions a and b are respectively t_dVa and t_dV_b. After the delay time of tau, the pulse of the exponential pulse voltage and the pulse of the square wave pulse voltage are generated, and the exponential pulse voltage and the square wave pulse voltage form an accelerating voltage on the accelerating electric field generating device, so that an accelerating electric field is generated in the accelerating electric field generating device. The cut-off speed of the ions a is low, the acceleration time in the acceleration electric field generating device is long, and the speed obtained after the ions a fly away from the acceleration electric field generating device is high and enter a field-free flight area of the drift tube; the cut-off speed of the ions b is high, the acceleration time in the acceleration electric field generating device is long, the speed obtained after the ions b fly away from the acceleration electric field generating device is high, and the ions enter a field-free flight area of the drift tube; the ion a follows the ion b in the field-free flight region, and the ion a and the ion b finally arrive at the detector at the same time.

The sample target and the leading-out pole piece are respectively loaded with exponential pulse voltage and square wave pulse voltage, namely, accelerating voltage which is easy to tune is loaded on the accelerating electric field generating device, the stability of the accelerating voltage is enhanced, and the interference of unstable accelerating voltage on ions is reduced, so that the ions with different mass numbers are accelerated accurately and stably, and the resolution ratio of the flight time mass spectrometer with a wide mass range is improved.

If negative ion detection is required, the amplitude voltages of the exponential pulse voltage and the square wave pulse voltage may be reversed, as shown in the negative ion detection of fig. 11, where fig. 11 is a pulse diagram of positive ion detection and negative ion detection in another embodiment.

If the detection is required to be carried out interactively between the positive ions and the negative ions, the voltage on the sample target and the extraction pole piece can be passed. For example, when detecting positive ions, inputting an exponential pulse voltage to a sample target and inputting a square wave pulse voltage with a lower voltage value to a leading-out pole piece; when negative ions need to be detected, exponential pulse voltage can be input into the extraction pole piece without changing the polarity of the voltage, and square wave pulse voltage with higher voltage value is input into the sample target, so that an accelerating electric field for accelerating the negative ions is generated.

The voltage applied to the first electrode may be an exponential pulse voltage, or may be another form of extraction pulse voltage, where the extraction pulse voltage is capable of causing an electric field to change in a certain form and is used to accelerate ions with different mass numbers so that the ions with different mass numbers can reach the detector.

The method of applying pulse to a single electrode by ion optical software-SIMION was compared with the simulation of the present invention, the waveform of the pulse applied to the single electrode is shown in FIG. 12, and Table 1 shows the electrical parameters of the voltage applied by the accelerated electric field generating apparatus under the simulation comparison. As shown in FIG. 12, FIG. 12 is a resolution curve simulated and compared in another embodiment, the optimal resolution curve obtained by the present invention is significantly better than the optimal resolution curve obtained by the original pulse application form, especially in the range of 1000-. FIG. 13 shows a mixed polypeptide mass spectrum of another embodiment, which shows that the time-of-flight mass spectrometer of the present invention obtains high resolution in a wide mass range in the range of 1000-3000Da, illustrating the feasibility of the present invention.

TABLE 1

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent application shall be subject to the appended claims.