A method for high-resolution isolation of target ions for mass spectrometry

Abstract

A method for isolating target ions with high resolution for a mass spectrometer comprises the following steps: S1, determining a SWIFT waveform based on the motion frequency of the isolated ions; S2, superimposing a sinusoidal waveform on the SWIFT waveform to obtain a SWIFTSIN isolation waveform, wherein the frequency of the sinusoidal waveform corresponds to the motion frequency of ions adjacent to the isolated ions; S3, applying the SWIFTSIN isolation waveform to the mass spectrometer, wherein the SWIFT waveform in the SWIFTSIN isolation waveform completes a coarse isolation process, exciting ions with mass-to-charge ratios far from the target ions while leaving the target ions and ions with adjacent mass-to-charge ratios, wherein the sinusoidal waveform in the SWIFTSIN isolation waveform completes the excitation of ions adjacent to the isolated ions. This method can reduce the space charge effect of miniaturized mass spectrometers for on-site detection, which is beneficial for improving the spectral resolution and the quantitative analysis capability of the instrument, thereby improving on-site detection efficiency.

Description

Technical Field

[0001] The present invention relates to, in particular to, a method for isolating target ions with high resolution for a mass spectrometer. Background Art

[0002] Mass spectrometry is a method that separates and detects substances based on the different motion states of ions of different mass-to-charge ratios in an electric or magnetic field. Its high sensitivity and rapid response have made it the "gold standard" for chemical testing. Mass spectrometry is widely used in food and drug analysis, explosives detection, and drug testing, and is playing an increasingly important role. Ion isolation is a key technique in mass spectrometry. By isolating ions of a specific mass-to-charge ratio in the mass analyzer and stimulating other ions, it can reduce space charge effects in the mass analyzer, improve spectral resolution and signal-to-noise ratio, and enhance the instrument's quantitative analysis capabilities. Tandem mass spectrometry, another key technique in mass spectrometry, also often requires a pre-process for ion isolation. By isolating ions of a specific mass-to-charge ratio and then performing collision-induced dissociation (CID), fragmentation information of the isolated precursor ions can be obtained, thereby improving the accuracy of substance identification.

[0003] Ion isolation is a key technology in assisting mass spectrometry analysis. Ion isolation avoids exciting ions with specific mass-to-charge ratios while exciting other ions, hence the term "ion-selective excitation." Resonant excitation is a widely used excitation technique. By applying an auxiliary AC excitation signal containing specific frequency components, it can selectively excite ions with the same motion frequency components. Currently, a widely used selective ion excitation technique is the stored waveform inverse Fourier transform (SWIFT). Before designing the isolation waveform, the motion frequencies of the ions in the mass analyzer are first calculated. Then, starting from the frequency domain, a rectangular broadband amplitude spectrum is designed. This spectrum contains a series of frequency components corresponding to the motion frequencies of the ions not to be isolated, thereby exciting these ions. It excludes the motion frequencies of the ions to be isolated, thereby isolating them in the ion trap mass analyzer. After the amplitude spectrum is designed, an inverse Fourier transform is performed in conjunction with quadratic phase modulation to obtain the isolation waveform.

[0004] Assuming that the amplitude of the rectangular amplitude spectrum is A0, the corresponding SWIFT waveform can be expressed as:

[0005]

[0006] Where p(w) is the quadratic phase function, which can be expressed as:

[0007]

[0008] Where w0 and w1 are the starting frequency and ending frequency of the waveform respectively, and t0 to t1 is the main time interval of the waveform energy distribution.

[0009] Figure 1 The frequency range is from 0 to 600kHz, the notch band is from 220kHz to 240kHz, the period is 21ms, and the signal energy is mainly concentrated in the signal from 0 to 15ms. Figure 1 (a), (b), and (c) are the time domain waveform, amplitude spectrum, and time-frequency diagram, respectively.

[0010] At a specific RF voltage, ions in the mass analyzer exhibit periodic motion, with ions of different mass-to-charge ratios exhibiting different frequencies. By applying an auxiliary AC excitation signal, as shown above, at a specific RF voltage amplitude, ions with frequencies between 220kHz and 240kHz are not excited, while ions with frequencies in other frequency ranges are excited. This allows the isolation of ions with frequencies between 220kHz and 240kHz at this RF voltage.

[0011] The SWIFT waveform is widely used in mass spectrometers to achieve ion isolation. Theoretically, increasing the RF voltage can increase the frequency interval of ion motion, thereby achieving high-resolution isolation (high-resolution isolation here refers to the ability to excite ions with a mass-to-charge ratio close to the isolated ion without affecting the intensity of the isolated ion). However, for miniaturized mass spectrometers used for on-site testing, the instrument's size limits the amplitude of the RF voltage, and the space charge effect of the smaller mass analyzer can negatively impact isolation. When applied to miniaturized mass spectrometers for on-site testing, the SWIFT waveform is unable to achieve high-resolution isolation. Simply reducing the notch width or increasing the amplitude of the frequency components at the notch edge will result in a loss of intensity for the isolated ions.

[0012] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0013] The main purpose of the present invention is to overcome the defects of the above-mentioned background technology and provide a method for isolating target ions with high resolution for a mass spectrometer.

[0014] To achieve the above object, the present invention adopts the following technical solutions:

[0015] A method for high-resolution isolation of target ions for a mass spectrometer comprises the following steps:

[0016] S1. Determine the SWIFT waveform based on the motion frequency of the isolated ions;

[0017] S2, superimposing a sinusoidal waveform on the SWIFT waveform to obtain a SWIFTSIN isolation waveform, wherein the frequency of the sinusoidal waveform corresponds to the motion frequency of the ions adjacent to the isolated ion;

[0018] S3. Apply the SWIFTSIN isolation waveform to the mass spectrometer, wherein the SWIFT waveform in the SWIFTSIN isolation waveform completes a coarse isolation process, excites ions with mass-to-charge ratios far away from the target ions, and leaves the target ions and ions with adjacent mass-to-charge ratios, wherein the sinusoidal waveform in the SWIFTSIN isolation waveform completes the excitation of ions adjacent to the isolated ions.

[0019] Further:

[0020] The width of the notch band of the SWIFT waveform is greater than a mass-to-charge ratio.

[0021] The width of the notch band of the SWIFT waveform is 3-5 mass-to-charge ratios.

[0022] In step S3, after the SWIFT waveform completes the coarse isolation, the sine waveform is applied to complete the fine isolation process.

[0023] The phase parameters of the SWIFT waveform are adjusted to compress the energy of the waveform in the first half of the cycle and superimpose the sinusoidal waveform in the second half.

[0024] The length and amplitude of the sinusoidal waveform are adjustable according to the intensity of the excited ions, wherein the amplitude is much lower than the amplitude of the SWIFT waveform.

[0025] When ions of a certain mass-to-charge ratio are isolated, the superimposed sinusoidal waveform includes two frequency components, and the two frequency components respectively correspond to the motion frequencies of the isolated ions with a mass-to-charge ratio of ±1.

[0026] When a plurality of ions of non-adjacent mass-to-charge ratios are isolated simultaneously, the frequency components of the superimposed sinusoidal waveforms are determined according to the mass-to-charge ratios of the excited ions.

[0027] The mass spectrometer is a miniaturized mass spectrometer for on-site detection.

[0028] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0029] The present invention has the following beneficial effects:

[0030] The present invention proposes a high-resolution isolation method suitable for on-site detection of miniaturized mass spectrometers. This method can achieve ion isolation of a single mass-to-charge ratio without changing the existing structure of the instrument and without increasing the length of the isolation waveform, thereby simplifying the secondary mass spectrum and facilitating the improvement of the on-site identification rate of sample ions. At the same time, collision-induced dissociation after high-resolution isolation facilitates a more direct correspondence between fragment ions and precursor ions, facilitating the establishment of a fragmentation pathway for precursor ions. The ion isolation method of the present invention has a significant effect on reducing the spatial charge effect of ion trap mass analyzers. The high-resolution isolation method can reduce the spatial charge effect of miniaturized mass spectrometers for on-site detection. When achieving isolation of non-adjacent multi-mass-to-charge ratio ions, it is beneficial to improving the spectral resolution and the quantitative analysis capability of the instrument, thereby improving on-site detection efficiency. The high-resolution isolation method of the present invention is particularly beneficial for improving the analytical performance of miniaturized mass spectrometers for on-site detection.

[0031] The high-resolution ion isolation method of the present invention enables per-unit mass isolation and resolution on a small, on-site mass spectrometer, simplifying secondary spectra and improving the speed of substance identification. Tandem mass spectrometry analysis, performed by isolating a single isotope of a precursor ion, facilitates inferring the molecular formula of the fragment ions and deriving the fragmentation pathway of the precursor ion. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a SWIFT signal with a frequency range of 0 to 600kHz and a notch band frequency of 220kHz to 240kHz.

[0033] Figure 2 This is a flow chart of SWIFTSIN waveform generation according to an embodiment of the present invention.

[0034] Figure 3 The frequency range of the embodiment of the present invention is 0-600kHz, the notch band frequency is 220kHz-240kHz, and the supplementary sinusoidal frequency is a SWIFT signal of 229.2kHz.

[0035] Figure 4 The excitation efficiencies at different frequencies under the conditions of 0.1 ms and 3 V0 (a) and 5 ms and 0.2 V0 (b) in the embodiment of the present invention are shown.

[0036] Figure 5 Figures 1 and 2 show the full scan spectrum (a) of an embodiment of the present invention (the inner part shows the spectrum after coarse isolation), the spectrum after exciting the m / z 357 ion (b), the spectrum after isolating the m / z 358 ion (c), the CID spectrum after coarse isolation (d), and the CID spectrum after isolating the m / z 358 ion (e). DETAILED DESCRIPTION

[0037] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0038] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and coupling or communication.

[0039] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0041] An embodiment of the present invention provides a method for high-resolution isolation of target ions for a mass spectrometer, comprising the following steps:

[0042] Determine the SWIFT waveform based on the movement frequency of the isolated ions;

[0043] Superimposing a sinusoidal waveform on the SWIFT waveform to obtain a SWIFTSIN isolation waveform, wherein the frequency of the sinusoidal waveform corresponds to the motion frequency of the ions adjacent to the isolated ion;

[0044] The SWIFTSIN isolation waveform is applied to the mass spectrometer, wherein the coarse isolation process is completed by the SWIFT waveform in the SWIFTSIN isolation waveform, ions with mass-to-charge ratios far away from the target ions are excited and the target ions and ions with adjacent mass-to-charge ratios are left, wherein the excitation of ions adjacent to the isolated ions is completed by the sinusoidal waveform in the SWIFTSIN isolation waveform.

[0045] In a preferred embodiment, after the SWIFT waveform completes the coarse isolation, the sine waveform is applied to complete the fine isolation process. The phase parameters of the SWIFT waveform are adjusted to compress the waveform energy in the first half of the cycle and superimpose the sine waveform in the second half.

[0046] The method of the embodiment of the present invention is particularly suitable for on-site detection of miniaturized mass spectrometers. It can realize the isolation of ions of a single mass-to-charge ratio without changing the existing structure of the instrument and without increasing the length of the isolation waveform, simplify the secondary mass spectrum, and facilitate the improvement of the on-site identification rate of sample ions. At the same time, collision-induced dissociation after high-resolution isolation facilitates the establishment of a more direct correspondence between the fragment ions and the precursor ions, and facilitates the establishment of a fragmentation pathway for the precursor ions. The ion isolation method of the present invention has a significant effect on reducing the spatial charge effect of the ion trap mass analyzer. The high-resolution isolation method can reduce the spatial charge effect of the on-site detection of miniaturized mass spectrometers. When realizing the isolation of non-adjacent multi-mass-to-charge ratio ions, it is beneficial to improving the spectral resolution and improving the quantitative analysis capability of the instrument, and can improve the efficiency of on-site detection. The high-resolution isolation method of the present invention is particularly beneficial for improving the analytical performance of on-site detection of miniaturized mass spectrometers.

[0047] Specific embodiments of the present invention are further described below.

[0048] The basic principle of high-resolution isolation waveform SWIFTSIN waveform

[0049] To achieve high-resolution isolation, the SWIFTSIN isolation waveform was designed. This isolation waveform is based on the SWIFT waveform by superimposing the energy of one or more frequency components. Specifically, the SWIFT waveform is used for coarse isolation, which excites ions with mass-to-charge ratios far from the target ion, while retaining the target ion and ions with adjacent mass-to-charge ratios. The SIN waveform, on the other hand, is a superimposed sinusoidal waveform whose frequency corresponds to the motion frequency of ions adjacent to the isolated ion and is used to excite the adjacent ions.

[0050] It should be noted that when more ions are stored in the ion trap mass analyzer of the mass spectrometer, the movement frequency of the ions will shift due to the influence of the space charge effect. At the same time, the existence of the space charge effect will also change the movement trajectory of the ions, resulting in mass shift, resolution reduction, etc. The notch band of the SWIFT waveform is set wider, preferably greater than a mass-to-charge ratio, and is used to complete the coarse isolation process of the ions. At this time, the influence of the space charge effect is not obvious, but when the superimposed sinusoidal frequency components are used to try to further excite the ions with adjacent mass-to-charge ratios of the isolated ions, the superimposed frequency is as close as possible to the actual movement frequency of the ions in the ion trap in order to achieve complete excitation of the adjacent ions of the isolated ions without causing erroneous excitation of the isolated ions. Therefore, it is preferred to apply a sinusoidal waveform to complete the fine isolation process after the SWIFT waveform isolation completes the coarse isolation.

[0051] Generate high-resolution isolated waveform SWIFTSIN waveform

[0052] Figure 2 The SWIFTSIN waveform generation process of one embodiment is shown. First, the motion frequency of the isolated ions is determined, the SWIFT waveform is designed, and then the sinusoidal excitation process is supplemented after the SWIFT waveform. In the flowchart, the waveform length affects the resolution of the isolated signal. In order to achieve a better isolation effect, the longer the length, the better. However, in actual isolation, the signal length does not need to be too large. When the isolation requirements are met, the shorter the length, the better (saving timing time). The optimal length of the SWIFT waveform and the SIN waveform can be determined by pre-experimentation based on the specific state of the instrument.

[0053] First, calculate the movement frequency of the isolated ions and design the SWIFT waveform. In order to complete the complete excitation of other non-isolated ions, the frequency component of the SWIFT waveform that is not 0 can be given a larger amplitude (such as 2.5V0), and in order to avoid the energy of the frequency component adjacent to the movement frequency of the isolated ions from causing false excitation of the isolated ions, a wider notch band (preferably a width of 3-5 mass-to-charge ratios) is set. In order not to increase the length of the isolation waveform and not to reduce the bandwidth and resolution of the SWIFT waveform after adding the sinusoidal waveform excitation process, the phase parameters of the SWIFT waveform are selected to compress the energy of the waveform in the first half of the cycle (such as Figure 1, the isolation waveform period is 21ms, but the energy is mainly concentrated in the first 15ms). Then a sine waveform is superimposed on the second half. The length and amplitude of the superimposed sine wave are adjustable according to the intensity of the excited ions, but the amplitude is much lower than the intensity of the SWIFT waveform (such as a sine wave with a length of 5ms and an amplitude of 0.25V0 can be used to complete the excitation of ions m / z357 with an intensity of 500mV without affecting the intensity of the ions around it), which is used to achieve fine excitation of ions with a mass-to-charge ratio adjacent to the target ion. When isolating ions of a certain mass-to-charge ratio, the superimposed sinusoidal waveform preferably contains two frequency components, which respectively correspond to the motion frequencies of the isolated ions with a mass-to-charge ratio of ±1. When isolating multiple non-adjacent mass-to-charge ratio ions at the same time, the superimposed frequency components are determined according to the mass-to-charge ratio of the excited ions.

[0054] Figure 3 It is a SWIFTSIN waveform with a frequency range of 0 to 600kHz and a notch band of 220kHz to 240kHz. A 5ms sine waveform is added to the second half of the SWIFT waveform, and the frequency of the sine wave is 229.2kHz.

[0055] High-resolution excitation principle of SIN waveform in SWIFTSIN waveform

[0056] The reason the supplemental sine waveform can excite ions with mass-to-charge ratios close to those of the isolated ions without causing false excitation of the isolated ions is that, compared to each frequency component in the SWIFT waveform, the duration of each supplemental sine wave excitation is prolonged and the intensity is weakened. This results in higher excitation resolution at this frequency. High excitation resolution here can be understood as significantly higher excitation efficiency for M ions than for M-1 and M+1 ions.

[0057] Figure 4 The excitation effects of a sine wave on pioglitazone ions (m / z 357, with two isotope ions at m / z 358 and m / z 359) at different exposure times and intensities are shown. The left figure shows an exposure time of 0.1 ms and an intensity of 3V0 for each frequency component, while the right figure shows an exposure time of 5 ms and an intensity of 0.2V0 for each frequency component. In the right figure, at a frequency of 199 kHz, the excitation efficiency of the m / z 358 ion exceeds 90%, while the excitation efficiency of the m / z 357 ion is less than 20%. In the left figure, at a frequency of 199 kHz, the excitation efficiency of three ions with adjacent mass-to-charge ratios all exceeds 90%. Therefore, the exposure method shown on the right can be said to provide higher resolution for ion excitation.

[0058] SWIFTSIN waveform unit mass isolation effect

[0059] SWIFTSIN waveform high resolution isolation capability can be reflected in unit mass isolation, Figure 5 The results using the SWIFTSIN waveform to isolate the ion m / z 358 are shown. The experimental sample was a mixture of rotundine, rosiglitazone, dioxetine hydrochloride, and repaglinide, with a final concentration of 1 ppm for each substance after mixing, and the solvent was pure methanol solution. Figure 5 (a) shows a full-scan mass spectrum, showing distinct peaks at each sample's mass-to-charge ratio. The peaks for rotundine and rosiglitazone show poor resolution. The SWIFT isolation waveform has a frequency range of 0 to 600 kHz, a notch band of 227 to 231 kHz, a waveform intensity of 2.5 V0, and a period of 21 ms. Figure 5 The inner image in middle (a) is the signal peak after rough isolation. It can be seen that the spectral signal resolution of rotundine and rosiglitazone is significantly improved after isolation, and the isotope peaks of rotundine and rosiglitazone appear. Figure 5 (b) shows the isolation effect after superimposing a sine wave waveform with a length of 5 ms, an intensity of 0.27V0, and a frequency of 229.2 kHz under the conditions of (a). It can be seen that under the action of the 229.2 kHz frequency, the ion of m / z 357 is excited, while the intensities of the ions of m / z 356 and m / z 358 remain unchanged, indicating that the SWIFTSIN waveform achieves fine excitation of the m / z 357 ion. Figure 5 Figures (c) through (d) show simplified secondary spectra after high-resolution isolation. The SWIFTSIN waveform superimposes four 5ms sine waves on the original SWIFT waveform, with frequencies of 230kHz, 229.2kHz, 227.8kHz, and 227.2kHz, and amplitudes of 0.23V0, 0.12V0, 0.12V0, and 0.23V0, respectively, to excite ions with mass-to-charge ratios of 356, 357, 359, and 360. Figure (c) shows the spectra before and after isolation, revealing that only the m / z 358 ion remains in the ion trap after isolation. Figure 5 (d) and (e) show the results of secondary mass spectrometry after SWIFT isolation and SWIFTSIN isolation. It can be seen that compared Figure 5 Middle (d), Figure 5 In (e), the fragment ions of rotundine disappear, and at the same time Figure 5 The inner panel of panel (e) shows the disappearance of the isotopic fragments of rosiglitazone after SWIFTSIN isolation. This is because the rosiglitazone m / z 359 isotope ion is excited during SWIFTSIN isolation. Therefore, the secondary mass spectrometry after isolation shows only fragments of the m / z 358 ion and not of the m / z 359 ion. This indicates that the isolated ion is indeed m / z 358.

[0060] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0061] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0062] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0063] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0064] The background section of the present invention may contain background information about the problem or environment of the present invention, but does not necessarily describe the prior art. Therefore, the inclusion of content in the background section is not an admission by the applicant that the prior art is present.

[0065] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. A method for high-resolution isolation of target ions for a mass spectrometer, characterized in that: The steps include: S1. Determine the SWIFT waveform based on the motion frequency of the isolated ions; S2, superimposing a sinusoidal waveform on the SWIFT waveform to obtain a SWIFTSIN isolation waveform, wherein the frequency of the sinusoidal waveform corresponds to the motion frequency of the ions adjacent to the isolated ion; S3. Apply the SWIFTSIN isolation waveform on the mass spectrometer, wherein the SWIFT waveform in the SWIFTSIN isolation waveform completes a coarse isolation process, excites ions with mass-to-charge ratios far from the target ions and leaves the target ions and ions with adjacent mass-to-charge ratios, wherein the sinusoidal waveform in the SWIFTSIN isolation waveform completes the excitation of ions adjacent to the isolated ions; wherein, after the SWIFT waveform completes the coarse isolation, the sinusoidal waveform is applied again to complete the fine isolation process; wherein the phase parameters of the SWIFT waveform are adjusted to compress the energy of the waveform in the first half of the period, and superimpose the sinusoidal waveform in the second half.

2. The method according to claim 1, wherein The width of the notch band of the SWIFT waveform is greater than a mass-to-charge ratio.

3. The method according to claim 2, wherein The width of the notch band of the SWIFT waveform is 3-5 mass-to-charge ratios.

4. The method according to any one of claims 1 to 3, wherein The length and amplitude of the sinusoidal waveform are adjustable according to the intensity of the excited ions, wherein the amplitude is much lower than the amplitude of the SWIFT waveform.

5. The method according to any one of claims 1 to 3, characterized in that When ions of a certain mass-to-charge ratio are isolated, the superimposed sinusoidal waveform includes two frequency components, and the two frequency components respectively correspond to the motion frequencies of the isolated ions with a mass-to-charge ratio of ±1.

6. The method according to any one of claims 1 to 3, wherein: When a plurality of ions of non-adjacent mass-to-charge ratios are isolated simultaneously, the frequency components of the superimposed sinusoidal waveforms are determined according to the mass-to-charge ratios of the excited ions.

7. The method according to any one of claims 1 to 3, characterized in that The mass spectrometer is a miniaturized mass spectrometer for on-site detection.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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