CN-122025505-A - Mass spectrum control method and system for improving sampling rate of ion trap mass spectrometer

CN122025505ACN 122025505 ACN122025505 ACN 122025505ACN-122025505-A

Abstract

The invention discloses a mass spectrum control method and a system for improving the sampling rate of an ion trap mass spectrometer, which relate to the technical field of mass spectrum analysis, the method is applied to the mass spectrometer provided with a discontinuous atmospheric pressure interface and a bilinear ion trap, the opening and the closing of an interface valve and the electric parameters of the two ion traps are cooperatively controlled, the two traps respectively execute two different operations of ion sample injection and gas supplementation in the same valve opening period, and execute the processes of fragmentation, spectrum scanning, transfer, selection and the like of the previous batch of ions in parallel in the subsequent steps. Therefore, the traditional serial analysis flow is changed into a time-interleaved parallel pipeline mode, the single analysis equivalent time is obviously shortened, and the sampling rate is improved by nearly one time at the highest. The invention is especially suitable for being combined with continuous separation devices such as liquid chromatography and the like, can effectively increase chromatographic peak sampling points, improves the accuracy and repeatability of quantitative analysis, and enhances the capturing capability of transient signals.

Inventors

WU JUNHAN
LI XIAOPENG
Bu Jiexuan

Assignees

清谱科技(苏州)有限公司
北京清谱科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. A mass spectrometry control method for increasing the sampling rate of an ion trap mass spectrometer, for use in a mass spectrometer equipped with a discontinuous atmospheric pressure interface and a dual linear ion trap mass analyser, the dual linear ion trap comprising a first ion trap and a second ion trap, the method comprising the steps of: step S1, in a first time period, opening the discontinuous atmospheric pressure interface, and simultaneously controlling the electric parameters of the mass spectrometer to enable ions to be detected to enter the second ion trap; s2, closing the discontinuous atmospheric pressure interface, and executing target ion selection operation on ions in the second ion trap after the atmospheric pressure in the vacuum cavity is reduced to a first preset condition; s3, opening the discontinuous atmospheric pressure interface again in a second time period, controlling the electric parameters of the mass spectrometer at the same time, enabling new ions to be detected to enter the first ion trap, and executing gas supplementing operation in the second ion trap; s4, closing the discontinuous atmospheric pressure interface, sequentially performing collision induction cracking operation and first spectrum scanning analysis on the ions selected in the step S2 in the second ion trap, and transferring the ions in the first ion trap to the second ion trap after the air pressure in the vacuum cavity is reduced to a second preset condition; step S5, repeatedly executing the steps S2 to S4, so that the analysis processes of ions of different batches are performed in time cross parallel.
2. The method according to claim 1, wherein in step S3, the simultaneous control is performed by adjusting at least one of radio frequency voltage, direct current voltage or excitation voltage applied to the first ion trap and the second ion trap such that one ion trap is in a state allowing ion trapping and storage to perform ion injection and the other ion trap is in a state allowing lifting of gas pressure in the trap and ion storage or manipulation to perform gas replenishment during the same valve opening period.
3. The method according to claim 1, wherein the first preset condition in step S2 is that the gas pressure in the vacuum chamber is reduced to a gas pressure range that allows ion mass selective isolation operation, and the second preset condition in step S4 is that the gas pressure in the vacuum chamber is reduced to a gas pressure range that allows axial transfer of ions from one ion trap to another ion trap.
4. The method according to claim 1, wherein in step S4, after the second ion trap performs the first scan analysis, the operation of transferring ions in the first ion trap to the second ion trap is started.
5. The method of claim 1, wherein subsequent target ion selection, collision induced fragmentation and second scan spectral analysis for the batch of ions are performed in the second ion trap after the ions in the first ion trap are transferred to the second ion trap.
6. A dual linear ion trap mass analyser for carrying out the method of any one of claims 1 to 5, comprising: a vacuum chamber; a non-continuous atmospheric pressure interface connected to said vacuum chamber; the first ion trap and the second ion trap are coaxially arranged in the vacuum chamber; and the control unit is configured to control the opening and closing of the discontinuous atmospheric pressure interface and independently control the electric parameters applied to the first ion trap and the second ion trap so as to realize that the two ion traps execute different ion operation steps in the same time period.
7. The dual linear ion trap mass analyzer of claim 6, wherein the control unit ensures that the original ion state in the ion trap that is performing the replenishment gas operation is not disturbed by newly incoming ions when the valve is opened for gas replenishment by coordinating the valve opening timing with the rf voltage timing of each ion trap.
8. A mass spectrometry system, comprising: A dual linear ion trap mass analyser according to claim 6 or 7; And the continuous separation device is used for continuously providing a sample to be tested and is connected with an ion source of the bilinear ion trap mass analyzer.
9. The mass spectrometry system of claim 8, wherein the continuous separation device is a liquid chromatograph or a capillary electrophoresis apparatus.
10. A computer storage medium having stored thereon a computer software product comprising instructions for causing a computer device to perform the mass spectrometry control method of increasing the sample rate of an ion trap mass spectrometer of any of claims 1 to 5.

Description

Mass spectrum control method and system for improving sampling rate of ion trap mass spectrometer Technical Field The invention relates to the technical field of mass spectrometry, in particular to a mass spectrometry control method and system for improving the sampling rate of an ion trap mass spectrometer. Background The ion trap mass spectrometer, in particular to a miniaturized ion trap mass spectrometer, has the advantages of high sensitivity and high specificity of mass spectrometry technology, has the characteristics of small volume, portability, simple and convenient operation and the like, and has wide application prospect in the field detection fields of public safety, instant medical detection and the like. The ion trap mass analyzer has a compact structure, relatively high working air pressure and tandem mass spectrometry capability, and is one of the key technical paths for the development of the current miniature mass spectrometer. In order to further promote miniaturization of a mass spectrometry system, a discontinuous atmospheric pressure interface is introduced into an ion trap mass spectrometry system, the interface is usually connected with an atmospheric environment and a vacuum cavity by adopting a pinch valve, pulse introduction of ions in an atmospheric pressure ion source is realized by quick opening and closing of a valve, and after the valve is closed, capturing, selecting, fragmentation and scanning analysis of the ions are sequentially completed in the process of natural pressure drop in the vacuum cavity. The system effectively reduces the requirement on the continuous air suction capability of the vacuum system, realizes the multi-stage mass spectrometry function in a single vacuum cavity, and becomes an important platform technology for miniaturization of mass spectrometry instruments. However, the workflow of a discontinuous atmospheric pressure interface ion trap mass spectrometer exhibits significant pulsing and timing dependencies when performing tandem mass spectrometry analysis. The typical secondary tandem mass spectrometry comprises the steps of opening a valve to introduce sample ions under atmospheric pressure, increasing the air pressure in a cavity, closing the valve, selecting and isolating target ions after the air pressure is reduced to a proper range, opening the valve again for short air supplementing to raise the background air pressure so as to realize collision-induced fragmentation, and then closing the valve, and carrying out mass scanning on fragment ions after the air pressure is reduced again. Each operation step corresponds to a specific air pressure interval, and waiting time required by air pressure change exists between the steps, so that a single analysis period is long. The whole analysis process must be performed strictly in sequence, i.e. after the completion of the previous complete sample-injection-selection-fragmentation-scanning cycle, before the next analysis can be started, as shown in fig. 1 and 2. The serial processing mode severely limits the sampling frequency of the mass spectrometer, particularly when coupling continuous sample separation devices such as liquid chromatography and the like, the longer single analysis time can lead to insufficient chromatographic peak sampling points, thereby affecting the accuracy of signal fitting, the repeatability of quantitative analysis and the capturing capability of transient signals, and restricting the performance of the technology in rapid and continuous detection scenes. Therefore, the discontinuous atmospheric pressure interface ion trap mass spectrometer in the prior art has the problems of long single analysis period and low sampling rate caused by the time sequence change of the air pressure, and a control method capable of optimizing the time sequence arrangement and improving the analysis flux is needed. Disclosure of Invention Therefore, the embodiment of the invention provides a mass spectrum control method and a mass spectrum control system for improving the sampling rate of an ion trap mass spectrometer, which are used for solving the problems of long single analysis period and low sampling rate caused by pressure time sequence change in the ion trap mass spectrometer with a discontinuous atmospheric pressure interface in the prior art. To solve the above technical problem, an embodiment of the present invention provides a mass spectrometry control method for increasing a sampling rate of an ion trap mass spectrometer, which is applied to a mass spectrometer equipped with a discontinuous atmospheric pressure interface and a dual linear ion trap mass analyzer, the dual linear ion trap including a first ion trap and a second ion trap, the method comprising the steps of: step S1, in a first time period, opening the discontinuous atmospheric pressure interface, and simultaneously controlling the electric parameters of the mass spectrometer to enable ions to be detected to enter the