CN108198741B

CN108198741B - Application mode of auxiliary regulating voltage AC

Info

Publication number: CN108198741B
Application number: CN201711208700.XA
Authority: CN
Inventors: 肖育; 姚如娇; 姜健; 顾义畅; 丁正知; 朱勇勇
Original assignee: SHANGHAI YUDA INDUSTRIAL CO LTD
Current assignee: SHANGHAI YUDA INDUSTRIAL CO LTD
Priority date: 2017-11-27
Filing date: 2017-11-27
Publication date: 2021-05-07
Anticipated expiration: 2037-11-27
Also published as: CN108198741A

Abstract

The invention discloses an application mode of auxiliary regulating voltage AC, wherein an auxiliary alternating current signal AC2 is added in the traditional linear ion trap electric signal application mode; the waveform of the auxiliary signal AC2 is a sine wave or a square wave with a certain frequency, and the amplitude of the sine wave or the square wave; the time period for which the auxiliary signal AC2 is applied is set to be an ion cooling phase or an ion collision induced dissociation phase. The method can be realized by the following three ways: 1) applying an auxiliary signal AC2 to the electrode in the non-ion emission direction; 2) applying an auxiliary signal AC2 to the electrode in the ion emission direction; 3) two auxiliary signals AC2 and AC3 were applied to the four electrodes of the ion trap. The method can effectively improve the ion cooling effect and the efficiency of ion collision induced dissociation, thereby improving the analysis performance of the linear ion trap.

Description

Application mode of auxiliary regulating voltage AC

Technical Field

The invention relates to the technical field of mass analyzers, in particular to an application mode of auxiliary regulation voltage AC.

Background

Mass spectrometry is a method of qualitatively and quantitatively analyzing substances by separating ions according to their mass-to-charge ratios by an electric field or a magnetic field, and instruments for analyzing using mass spectrometry are collectively called mass spectrometers. The mass spectrometer is a representative of modern high-end analytical instruments, and is an effective tool for trace detection of low-content substances due to the advantages of strong qualitative and quantitative capability, high sensitivity, detection limit and the like. At present, mass spectrometry instruments have been widely used in the fields of food safety, life sciences, medical testing, environmental monitoring, public safety, aerospace, and the like. More and more national standards, industry standards and analytical detection methods are being developed based on mass spectrometry instruments.

The mass analyzer is a core component of a mass spectrometer, and the mass spectrometer can be classified into a magnetic mass spectrometer, a fourier transform-ion cyclotron resonance mass spectrometer, an ion trap mass spectrometer, a quadrupole mass spectrometer, and a time-of-flight mass spectrometer according to the difference of the mass analyzer. The ion trap mass spectrometer can better perform multi-stage mass spectrometry with good ion storage capacity, so that the overall analysis performance of the instrument is improved. The core ion trap mass analyzer (hereinafter referred to as ion trap) has the characteristics of small size, simple structure, easy processing, loose requirements on working air pressure and the like, and becomes a research hotspot in the field of mass spectrometry in two years.

Currently, commonly used ion trap mass spectrometers include three-dimensional ion trap mass spectrometers and linear ion trap mass spectrometers. A three-dimensional ion trap mass analyzer is comprised of two hyperboloid end cap electrodes and a rotating hyperboloid ring electrode, and during mass analysis, ions are stored in a spherical region in the center of the three-dimensional ion trap. The linear ion trap mass analyzer is composed of two pairs of hyperbolic cylindrical surfaces and two end cover electrodes which are symmetrically arranged, and ions are stored in a cylindrical area in the center of the linear ion trap in the mass analysis process. Compared with a three-dimensional ion trap, the linear ion trap has a larger ion storage space, so that more ions can be stored, the analysis sensitivity is improved, the space charge effect is avoided, and the quality resolution is ensured to meet the analysis requirement.

The radio frequency power supply is a key component and an important component of the linear ion trap mass spectrometer, and only the radio frequency power supply and the ion trap mass analyzer are organically combined can a quadrupole electric field required by mass analysis be effectively formed. The resonance excitation signal module coupled by the radio frequency signal is an important part of the whole circuit system. The functions of the resonance excitation signal are many: firstly, in the mass analysis process, the ion motion has a natural frequency, when the applied resonance excitation frequency is consistent with the natural frequency of the ions, the ions resonate and are emitted from a trap to be detected; secondly, when the multistage tandem mass spectrometry is carried out, a resonance excitation signal with a small amplitude needs to be applied to enable ions to generate Collision Induced Dissociation (CID); in the processes of ion mass selective isolation and mass selective ejection, a resonance excitation module is required to output a specific signal waveform.

The excitation signal AC (hereinafter referred to as AC1 for the difference) is generally applied to the electrodes in the ion exit direction in a dipole manner, as shown in fig. 1. Taking a linear ion trap with semi-arc electrodes as an example, an AC1 signal given by a measurement and control system is directly coupled to radio frequency RF through two identical secondary coils T1 and T2, and since an excitation signal AC1 is only applied to the electrodes in the x direction, T2 is grounded to ensure that the outputs of two coupled radio frequency RF signals are balanced. It has also been reported that excitation signal AC1, i.e., a dual AC1 signal, can be applied to both the x-direction and y-direction electrodes to improve the mass analysis performance of the linear ion trap.

The linear ion trap mass analysis process is generally divided into an ionization sampling stage, an ion cooling stage, a mass scanning stage and an ion clearing stage, wherein an excitation signal AC1 is generally only used as an excitation signal and works in an ion isolation, CID or ion analysis stage, and other stages such as the ion sampling stage, the ion cooling stage and the like are generally not applied with an AC1 signal. No research has been conducted to determine whether the application of an auxiliary AC signal during the entire mass analysis process, except during the scanning phase, promotes and optimizes the performance of the mass analysis of the linear ion trap.

Disclosure of Invention

In order to realize the pneumatic pressurization technology, the invention provides an auxiliary regulation voltage AC application mode to improve the analysis performance of the linear ion trap.

The purpose of the invention is realized by the following technical scheme: an auxiliary adjusting voltage AC application mode is characterized in that an auxiliary alternating current signal AC2 is added in a traditional linear ion trap electric signal application mode; the waveform of the auxiliary signal AC2 is a sine wave or a square wave with a certain frequency, and the amplitude of the sine wave or the square wave; the time period for which the auxiliary signal AC2 is applied is set to be an ion cooling phase or an ion collision induced dissociation phase. The method can be realized by the following three ways:

1) applying an auxiliary signal AC2 to the electrode in the non-ion emission direction;

2) applying an auxiliary signal AC2 to the electrode in the ion emission direction;

3) two auxiliary signals AC2 and AC3 were applied to the four electrodes of the ion trap.

The auxiliary signal AC2 works simultaneously with the excitation signal AC1 in and only during the ion collision induced dissociation phase (CID).

The auxiliary signal AC2 may or may not be identical in amplitude, frequency and phase to the excitation signal AC 1.

Preferably, two auxiliary signals AC2 and AC3 may be applied, one to each set of electrodes of the linear ion trap; the amplitude, frequency and phase of the auxiliary signals AC2 and AC3 may or may not be identical. The auxiliary signals AC2 and AC3 may be operated simultaneously, or at least one auxiliary AC2 or AC3 may be operated during the ion collision induced dissociation phase or the ion cooling phase.

Compared with the prior art, the method for applying the auxiliary regulating voltage AC provided by the invention can effectively improve the ion cooling effect and the efficiency of ion collision induced dissociation, thereby improving the analysis performance of the linear ion trap.

Drawings

Fig. 1 is a schematic diagram of a linear ion trap with excitation signal AC1 voltage applied in a dipole fashion to semi-circular arc electrodes: 101 is a semi-arc electrode linear ion trap, 102 and 103 are secondary coils, 104 is a radio frequency power supply, 105 is an excitation signal AC, and 106 is an inductance matching terminal.

Fig. 2 is a schematic diagram of an application manner of the auxiliary signal AC2 in embodiment 1 of the present invention.

Fig. 3 is a schematic diagram of voltage signals of the excitation signal AC1 and the auxiliary signal AC2 in embodiment 1 of the present invention.

Fig. 4 is a schematic diagram of an application manner of the auxiliary signal AC2 in embodiment 2 of the present invention.

Fig. 5 is a schematic diagram of the application manner of the auxiliary signals AC2 and AC3 in embodiment 3 of the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Example 1

One embodiment of the auxiliary regulation voltage AC is shown in fig. 2. Wherein 201 is a semi-arc electrode linear ion trap, 202 and 203 are secondary coils, 204 is an excitation signal AC1, 205 is an auxiliary signal AC2, and 206 is a radio frequency power supply. In this embodiment, the excitation signal AC2 is coupled to the negative terminal of the rf power source via the secondary coil 202 and applied to the x-direction electrodes; the auxiliary signal AC2 is coupled to the positive side of the radio frequency RF through the secondary coil 203 and is applied to the electrodes in the y-direction. In the mass analysis process, the excitation signal AC1 works only in the ion collision induced dissociation phase or the scanning phase, the auxiliary signal AC2 works only in the ion collision induced dissociation phase or the ion cooling phase, the voltage signals of AC1 and AC2 are shown in fig. 3, and the amplitudes and frequencies of the two signals can be the same or different, and the phases can be the same as or opposite to those shown in fig. 3(a) or the opposite to those shown in fig. 3 (b). The auxiliary AC2 signal is applied in the ion induced dissociation stage to effectively improve the ion collision fragmentation efficiency, and the auxiliary signal AC2 is applied in the ion cooling stage to effectively improve the ion cooling efficiency, which is beneficial to effectively improving the analysis performance of the linear ion trap.

Example 2

One embodiment of the auxiliary regulation voltage AC is shown in fig. 4. Wherein 401 is a semi-circular arc electrode linear ion trap, 402 is a radio frequency power supply RF, 403, 404, 407, 408 are secondary coils, 405 is an excitation signal AC1, 406 is an auxiliary signal AC2, 409 and 410 are corresponding inductance matching ground terminals. In this embodiment, the excitation signals AC1 and AC2 are coupled to the negative side of the rf power source via the

secondary coils

403 and 404, respectively, and are applied to the x-direction electrodes. Because the electrode in the x direction is coupled with 2 paths of AC signals, 2 inductors are required to be coupled with the grounding terminal corresponding to the electrode in the y direction, and the radio frequency RF signals on the electrode in the x direction and the electrode in the y direction are ensured to be balanced. The difference between the embodiment and the embodiment 1 is that the auxiliary adjusting voltage AC2 is also applied to the electrode in the ion emergence direction, and in the ion induced dissociation stage, the excitation signal AC1 and the auxiliary signal AC2 can work simultaneously, so that the ion dissociation efficiency is effectively improved; in the ion cooling stage, the excitation signal AC1 does not work, and the auxiliary signal AC2 works, so that the ion cooling efficiency is improved; in the mass scanning stage, the auxiliary signal AC2 is not operated, and the excitation signal AC1 is operated, so that the mass scanning process is completed. In this example, although the electrodes to which the auxiliary signal AC2 is applied are different from those in example 1, the purpose to be finally achieved and the effect to be achieved are the same.

Example 3

One way of applying the auxiliary regulation voltage AC is shown in fig. 5. Wherein 501 is a semi-circular arc electrode linear ion trap, 502 is a radio frequency power supply RF, 503, 504, 507, 508 are secondary coils, 505 is an excitation signal AC1, 506 is an auxiliary signal AC2, 509 is an auxiliary signal AC3, and 510 is a corresponding inductance matching ground. The difference between this example and the above described embodiment is that two auxiliary signals AC2 and AC3 are applied. The excitation signal AC1 and the auxiliary signal AC2 are coupled to the negative side of the radio frequency RF through the

secondary coils

503 and 504, respectively, applied to the x-direction electrodes; the auxiliary signal AC3 is coupled to the positive side of the RF signal through the secondary coil 507, while the inductive matching ground 510 ensures that the RF signals RF on the two sets of electrodes are balanced. The advantage of this embodiment lies in adopting double-circuit auxiliary signal AC2 and AC3, and this will be more favorable to improving the efficiency that ion collision induced dissociation, and the better messenger ion that can be simultaneously in the ion cooling stage cools down, is carried out mass analysis by stable transmission to linear ion trap inside, effectively improves mass analysis performance.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims

1. An auxiliary regulation voltage AC application mode is characterized in that an auxiliary alternating current signal AC2 is added in the application of a linear ion trap electric signal; the waveform of the auxiliary signal AC2 is a sine wave or a square wave with a certain frequency; the time period for which the auxiliary signal AC2 is applied is set to an ion cooling phase or an ion collision induced dissociation phase;

applying an auxiliary signal AC2 on the electrode in the ion emergence direction, applying an auxiliary signal AC2 on the electrode in the non-ion emergence direction, or applying two auxiliary signals AC2 and AC3 on the four electrodes of the ion trap;

the auxiliary signal AC2 and the excitation signal AC1 work simultaneously in and only in the ion collision induced dissociation phase;

the ion trap adopts a semi-arc electrode linear ion trap, the excitation signal AC1 voltage is applied to the semi-arc electrode linear ion trap in a dipole mode, and the auxiliary signals AC2 and AC3 can work simultaneously or at least one auxiliary AC2 or AC3 works in the ion cooling stage.

2. An auxiliary regulation voltage AC as claimed in claim 1 wherein the auxiliary signal AC2 is substantially identical in amplitude, frequency and phase to the excitation signal AC 1.

3. An auxiliary regulation voltage AC as claimed in claim 1 wherein the auxiliary signal AC2 is substantially non-identical in amplitude, frequency and phase to the excitation signal AC 1.

4. An auxiliary regulation voltage AC application as claimed in claim 1 wherein two auxiliary signals AC2 and AC3 may be applied, one to each set of electrodes of the linear ion trap; the amplitude, frequency and phase of the auxiliary signals AC2 and AC3 may or may not be identical.