A system and method for qualitative identification of compounds based on dual mode mass spectrometry analysis

Abstract

The application discloses a compound qualitative identification system and method based on a dual-mode mass spectrum analysis, which utilizes a quadrupole mass spectrometer and an orbitrap mass spectrometer to synchronously provide spectrum information; taking the spectrum of the quadrupole mass spectrometer as an index, a plurality of matching results are obtained through NIST spectrum library retrieval, each matching result comprises a compound name, a matching degree and a possibility; if the matching degree and the possibility both reach a threshold value, the corresponding compound name is taken as a qualitative result; otherwise, the matching degrees are arranged from high to low, the first N matching results are taken as candidate results, and the theoretical mass numbers of fragment ions of the corresponding candidate compounds are determined respectively; the measured mass numbers are determined according to the spectrum information provided by the orbitrap mass spectrometer; the mass accuracies of the N candidate compounds are calculated respectively; the mass accuracies less than or equal to a threshold value are screened and arranged from low to high, and the candidate compounds corresponding to the first M mass accuracies are reserved as qualitative results.

Description

Technical Field

[0001] This invention relates to the field of mass spectrometry analysis, and more particularly to a system and method for qualitative identification of compounds based on dual-mode mass spectrometry analysis. Background Technology

[0002] In gas chromatography-mass spectrometry (GC-MS), traditional low-resolution mass spectrometry identifies compounds by combining information from chromatographic retention time, mass spectrometric fragment ions, and molecular ion peaks with databases (such as NIST). However, the following problems exist in practical applications:

[0003] First, the molecular ion peak is missing: most compounds produce abundant fragment ions during ionization, resulting in weak or missing molecular ion peak signals, which leads to insufficient qualitative evidence.

[0004] Second, homologue / isomeric interference: fragment ion spectra of structurally similar compounds (such as organophosphates and carbamates in pesticide residues) overlap significantly, which can easily lead to misjudgment.

[0005] Third, high-resolution mass spectrometry data overload: Although high-resolution mass spectrometry such as orbital traps can provide accurate mass numbers (<5ppm), the number of fragment ions surges, and a large number of highly similar candidate compounds are generated after database matching. The time cost of manual screening is very high, and the basic knowledge required of the operators is also very high.

[0006] Currently, it is difficult to quickly and accurately identify compounds using gas chromatography-mass spectrometry.

[0007] The disclosure of the above background technical content is only for the purpose of assisting in understanding the concept and technical solution of this application, and does not necessarily provide technical instruction. Summary of the Invention

[0008] The purpose of this invention is to provide an identification system for precise qualitative analysis of compounds by combining quadrupole mass spectrometry and high-resolution orbital trap mass spectrometry with NIST MSSearch.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A compound qualitative identification system based on dual-mode mass spectrometry includes an ion source, a quadrupole mass spectrometer, an orbital trap mass spectrometer, and an analyzer, wherein the quadrupole mass spectrometer and the orbital trap mass spectrometer are configured to simultaneously provide their respective spectral information;

[0011] The analyzer uses the quadrupole mass spectra as an index to retrieve multiple matching results from the NIST spectral library. Each matching result includes the compound name, matching degree, and probability.

[0012] If a matching result exists that meets both a preset matching threshold and a preset probability threshold, then the compound name corresponding to that matching result is used as the qualitative result; otherwise, the analyzer continues to execute the following steps:

[0013] The matching results are arranged from high to low according to the matching degree. The top N matching results are taken as candidate results, and the theoretical mass number of the fragment ions of the corresponding candidate compounds is determined, where N is an integer.

[0014] The measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer.

[0015] Based on the theoretical mass number and the measured mass number, calculate the mass accuracy of each of the N candidate compounds;

[0016] The quality precision is selected from those that are less than or equal to the preset precision threshold. If the number of selected samples is greater than M, the selected quality precision is arranged from low to high, and the candidate compounds corresponding to the top M quality precision are retained as the qualitative results, where 0 < M ≤ N / 2.

[0017] Furthermore, in accordance with any or a combination of the aforementioned technical solutions, a deflection focusing lens group is also provided between the quadrupole mass spectrometer and the orbital trap mass spectrometer;

[0018] The quadrupole mass spectrometer includes a quadrupole, a linear ion trap, a darad electrode, and an electron multiplier. The linear ion trap is provided with an opening for lateral deflection of ions, so that a portion of the ions output from the ion source are transmitted to the darad electrode, and another portion of the ions are transmitted to the orbital trap of the orbital trap mass spectrometer after passing through the opening of the linear ion trap and the deflection focusing lens group.

[0019] Furthermore, following any one or a combination of the aforementioned technical solutions, the system further includes a GC transfer line and a filament, wherein the filament is configured to heat the GC transfer line, and the GC transfer line is configured to allow sample molecules to enter the ion source from the chromatographic column of the gas chromatograph in gaseous form.

[0020] Furthermore, following any one or a combination of the aforementioned technical solutions, the theoretical mass number of the fragment ions of the compound is determined in the following manner:

[0021] The molecular structure of the candidate compound is input into the mass spectrometer data processing software, which simulates the compound's fracture path based on the built-in fragmentation mechanism to predict the precise mass of the fragment ions that will be generated after the fracture.

[0022] Furthermore, following any one or a combination of the aforementioned technical solutions, the measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer in the following manner:

[0023] In response to selecting a corresponding target peak in the total ion chromatogram obtained by the orbital trap mass spectrometry scan, the system generates a mass spectrum of the retention time corresponding to the target peak and displays the measured mass number of the target peak on the mass spectrum.

[0024] Furthermore, based on any one or a combination of the aforementioned technical solutions, the mass accuracy of the compound is calculated using the following formula:

[0025] Quality accuracy = [(Measured mass number - Theoretical mass number) / Theoretical mass number] × 10 6 ;

[0026] If the minimum mass precision among the N candidate compounds is greater than the precision threshold, a qualitative failure is indicated, and / or the candidate compound with the minimum mass precision is output as a reference.

[0027] Furthermore, following any one or a combination of the aforementioned technical solutions, N≤20, or N≤15, or N≤10;

[0028] M=4, or M=3, or M=2, or M=1.

[0029] Furthermore, based on any one or a combination of the aforementioned technical solutions, the orbital trap mass spectrometer has a resolution of less than or equal to 5 ppm;

[0030] The preset accuracy threshold value ranges from less than or equal to 5 ppm.

[0031] According to another aspect of the present invention, the present invention provides a method for qualitative identification of compounds based on dual-mode mass spectrometry analysis, comprising the following steps:

[0032] An ion source is configured to simultaneously trigger a quadrupole mass spectrometer and an orbital trap mass spectrometer, causing a portion of the ions output from the ion source to be transported to the dynamo pole of the quadrupole mass spectrometer, and causing another portion of the ions to be deflected and transported to the orbital trap of the orbital trap mass spectrometer. The quadrupole mass spectrometer generates a first spectrum, and the orbital trap mass spectrometer generates a second spectrum.

[0033] Using the first spectrum as an index, multiple matching results are obtained by searching the NIST spectral library. Each matching result includes the compound name, matching degree, and probability.

[0034] If a matching result exists that meets both the preset matching degree threshold and the preset probability threshold, then the compound name corresponding to that matching result is used as the qualitative result; otherwise, continue with the following steps:

[0035] The matching results are arranged from high to low according to the matching degree. The top N matching results are taken as candidate results, and the theoretical mass number of the fragment ions of the corresponding candidate compounds is determined, where N is an integer.

[0036] The measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer.

[0037] Based on the theoretical mass number and the measured mass number, calculate the mass accuracy of each of the N candidate compounds;

[0038] The quality precision is selected from those that are less than or equal to the preset precision threshold. If the number of selected samples is greater than M, the selected quality precision is arranged from low to high, and the candidate compounds corresponding to the top M quality precision are retained as the qualitative results, where 0 < M ≤ N / 2.

[0039] Furthermore, following any one or a combination of the aforementioned technical solutions, the theoretical mass number of the fragment ions of the compound is determined by the following method: inputting the molecular structure of the candidate compound into the mass spectrometer data processing software, simulating the compound's fracture path based on the built-in fragmentation mechanism, in order to predict the precise mass of the fragment ions that generate charged fragments after fracture.

[0040] The measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer in the following manner: in response to selecting the corresponding target peak in the total ion chromatogram obtained by the orbital trap mass spectrometer scan, a mass spectrum of the retention time corresponding to the target peak is generated, and the measured mass number of the target peak is displayed on the mass spectrum.

[0041] The mass accuracy of a compound is calculated using the following formula: Mass accuracy = [(Measured mass number - Theoretical mass number) / Theoretical mass number] × 10 6 ;

[0042] If the minimum mass precision among the N candidate compounds is greater than the precision threshold, a qualitative failure is indicated, and / or the candidate compound with the minimum mass precision is output as a reference, wherein N≤20, or N≤15, or N≤10; M=4, or M=3, or M=2, or M=1.

[0043] The beneficial effects of the technical solution provided by this invention are as follows:

[0044] a. Using quadrupole mass spectrometry data for NIST library search and matching, and using orbital trap mass spectrometry data for mass accuracy matching, demonstrates cross-validation of dual-mode data, significantly reducing the risk of misjudgment of homologues / isomers and reducing the need for human intervention;

[0045] b. The dual-mode mass spectrometer simultaneously triggers quadrupole mass spectrometry and high-resolution orbital trap mass spectrometry to obtain two mass spectra at the same time. Combined with NIST MS Search, it enables accurate identification of compounds.

[0046] c. The identification method is simple to operate and requires relatively low knowledge from the identification personnel. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A schematic diagram of a dual-mode mass spectrometer provided as an exemplary embodiment of the present invention;

[0049] Figure 2 A flowchart for qualitative identification of compounds based on dual-mode mass spectrometry analysis is provided as an exemplary embodiment of the present invention.

[0050] Figure 3 A total ion current (TIC) plot obtained by quadrupole scanning (Q Scan) is provided as an exemplary embodiment of the present invention;

[0051] Figure 4 for Figure 3 The mass spectrum corresponding to a retention time of 21.848 min is shown.

[0052] Figure 5 A total ion current (TIC) plot obtained by an orbital trap FT scan is provided as an exemplary embodiment of the present invention;

[0053] Figure 6 for Figure 5 The mass spectrum corresponding to a retention time of 21.848 min is shown.

[0054] Figure 7 According to Figure 4 The list of compounds obtained by searching the mass spectra;

[0055] Figure 8 According to Figure 6 The list is obtained by searching for compounds using the mass spectrum. Detailed Implementation

[0056] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0057] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0058] In one embodiment of the present invention, a compound qualitative identification system based on dual-mode mass spectrometry is provided, including an ion source 100, a quadrupole mass spectrometer, an orbital trap mass spectrometer, and an analyzer. The quadrupole mass spectrometer and the orbital trap mass spectrometer are configured to simultaneously provide their respective spectral information. The mass spectrum resolution of the quadrupole mass spectrometer is lower than that of the orbital trap mass spectrometer. In one embodiment of the present invention, the mass spectrum resolution of the quadrupole mass spectrometer is between 0.35 amu and 2 amu, or 0.35 amu to 1 amu, and the mass spectrum resolution of the orbital trap mass spectrometer is ≤5 ppm. The identification system is used to identify sample compounds, such as... Figure 1 As shown, the system also includes a GC transfer line 200 and a filament 300, wherein the filament 300 is configured to heat the GC transfer line 200, and the GC transfer line 200 is configured to allow sample molecules to enter the ion source from the chromatographic column of the gas chromatograph in gaseous form.

[0059] like Figure 1 As shown, a deflection focusing lens group 400 is also provided between the quadrupole mass spectrometer and the orbital trap mass spectrometer; the quadrupole mass spectrometer includes a quadrupole 500, a linear ion trap 600, a dinter electrode 700 and an electron multiplier 800, wherein the linear ion trap is provided with an opening for lateral deflection of ions, so that a portion of the ions output from the ion source are transmitted to the dinter electrode 700, and another portion of the ions are transmitted to the orbital trap 900 of the orbital trap mass spectrometer after passing through the opening of the linear ion trap and the deflection focusing lens group 400.

[0060] like Figure 2 As shown, the analyzer identifies the sample compounds through the following steps:

[0061] S100: Using the quadrupole mass spectra as an index, multiple matching results are obtained by searching the NIST spectral library. Each matching result includes the compound name, matching degree, and probability.

[0062] NIST MS Search is a specialized software for analyzing and identifying mass spectrometry data, particularly adept at identifying unknown compounds. Its core function is spectral library retrieval, which can be considered a "compound fingerprint database" or a "mass spectrum search engine." NIST MS Search compares an input unknown mass spectrum with millions of spectra of known compounds in its vast built-in standard spectral library, and then outputs a ranking list of matching scores, listing the known compounds most similar to the unknown mass spectrum and providing a score for the matching degree.

[0063] Unlike conventional methods that rely on matching scores to quickly identify compounds, this application utilizes NIST MS Search, which also returns a "probability" index. This invention not only considers the matching score but also combines probability to comprehensively evaluate the true likelihood of the identification results. Mass spectrometry plays a very important role in this comprehensive evaluation, as explained in steps S210-S240 below.

[0064] S200: If a matching result exists that meets both a preset matching degree threshold and a preset probability threshold, the compound name corresponding to that matching result is used as the qualitative result. In this embodiment, the higher the set values ​​of the matching degree threshold and the probability threshold, the more accurate the qualitative result will be once the conditions are met. Even if a correct matching result is "passed" in step S200 because it does not meet the requirement that both the matching degree and probability thresholds are met, it does not prevent it from being qualitatively determined again by continuing to execute the following steps through the analyzer:

[0065] S210: Arrange the matching results in descending order of matching degree, take the top N matching results as candidate results, and determine the theoretical mass number of the fragment ions of the corresponding candidate compounds, where N is an integer;

[0066] Specifically, the theoretical mass number of fragment ions of a compound is determined by inputting the molecular structure of the candidate compound into the mass spectrometer data processing software, simulating the compound's fracture path based on the built-in fragmentation mechanism, and predicting the precise mass of the fragment ions that will be generated after fracture.

[0067] S220: Determine the measured mass number based on the spectral information provided by the orbital trap mass spectrometer, as follows:

[0068] In response to selecting a corresponding target peak in the total ion chromatogram obtained by the orbital trap mass spectrometry scan, the system generates a mass spectrum of the retention time corresponding to the target peak and displays the measured mass number of the target peak on the mass spectrum.

[0069] S230: Based on the theoretical mass number and the measured mass number, calculate the mass accuracy of each of the N candidate compounds using the following formula;

[0070] Quality accuracy = [(Measured mass number - Theoretical mass number) / Theoretical mass number] × 10 6 ;

[0071] S240: Filter the quality precision that is less than or equal to the preset precision threshold. If the number of filtered products is greater than M, then sort the filtered quality precision from low to high and retain the candidate compounds corresponding to the first M quality precision as the qualitative results, where 0 < M ≤ N / 2.

[0072] In this embodiment, the resolution of the orbital trap mass spectrometer is less than or equal to 5 ppm, and the preset accuracy threshold range is less than or equal to 5 ppm.

[0073] S250: If the minimum mass precision among the N candidate compounds is greater than the precision threshold, a qualitative failure is indicated, and / or the candidate compound with the minimum mass precision is output as a reference.

[0074] In one embodiment of the present invention, the value of N can be 20, 15, or 10, and the value of M can be 4, 3, 2, or 1. Using the above identification steps, the number of candidate compounds can be reduced from tens or even hundreds to single digits, reducing the workload of manual verification by more than 90%. In step S100, quadrupole mass spectrometry data is used for NIST library search and matching; in steps S220 to S250, orbital trap mass spectrometry data is used for mass accuracy matching. This demonstrates cross-validation using dual-mode data, significantly reducing the risk of misidentification of homologues / isomers and minimizing the need for manual intervention.

[0075] In one embodiment of the present invention, a method for qualitative identification of compounds based on dual-mode mass spectrometry is provided, such as... Figure 2 As shown, it includes the following steps:

[0076] An ion source is configured to simultaneously trigger a quadrupole mass spectrometer and an orbital trap mass spectrometer, causing a portion of the ions output from the ion source to be transported to the dynamo pole of the quadrupole mass spectrometer, and causing another portion of the ions to be deflected and transported to the orbital trap of the orbital trap mass spectrometer. The quadrupole mass spectrometer generates a first spectrum, and the orbital trap mass spectrometer generates a second spectrum.

[0077] Using the first spectrum as an index, multiple matching results are obtained by searching the NIST spectral library. Each matching result includes the compound name, matching degree, and probability.

[0078] If a matching result exists that meets both the preset matching degree threshold and the preset probability threshold, then the compound name corresponding to that matching result is used as the qualitative result; otherwise, continue with the following steps:

[0079] The matching results are arranged from high to low according to the matching degree. The top N matching results are taken as candidate results, and the theoretical mass number of the fragment ions of the corresponding candidate compounds is determined, where N is an integer.

[0080] The measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer.

[0081] Based on the theoretical mass number and the measured mass number, calculate the mass accuracy of each of the N candidate compounds;

[0082] The quality precision is selected from those that are less than or equal to the preset precision threshold. If the number of selected samples is greater than M, the selected quality precision is arranged from low to high, and the candidate compounds corresponding to the top M quality precision are retained as the qualitative results, where 0 < M ≤ N / 2.

[0083] Furthermore, following any one or a combination of the aforementioned technical solutions, the theoretical mass number of the fragment ions of the compound is determined by the following method: inputting the molecular structure of the candidate compound into the mass spectrometer data processing software, simulating the compound's fracture path based on the built-in fragmentation mechanism, in order to predict the precise mass of the fragment ions that generate charged fragments after fracture.

[0084] The measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer in the following manner: in response to selecting the corresponding target peak in the total ion chromatogram obtained by the orbital trap mass spectrometer scan, a mass spectrum of the retention time corresponding to the target peak is generated, and the measured mass number of the target peak is displayed on the mass spectrum.

[0085] The mass accuracy of a compound is calculated using the following formula: Mass accuracy = [(Measured mass number - Theoretical mass number) / Theoretical mass number] × 10 6 ;

[0086] If the minimum mass precision among the N candidate compounds is greater than the precision threshold, a qualitative failure is indicated, and / or the candidate compound with the minimum mass precision is output as a reference, wherein N≤20, or N≤15, or N≤10; M=4, or M=3, or M=2, or M=1.

[0087] Figures 3 to 8A specific embodiment is shown using a Cassitrap 120K mass spectrometry system to test a mixed standard sample of pesticide residues (Group A) in the national standard. The sample was tested using both quadrupole scanning (Q Scan) and high-resolution scanning (FT Scan). After obtaining the total ion chromatogram, a single chromatographic peak was selected for mass spectrometry analysis. The more types of compounds in a mixed sample, the more difficult it is to qualitatively identify each compound. The advantage of this invention lies in its accurate identification of multiple compounds in a mixed sample; see [link to relevant documentation]. Figures 3 to 6 :

[0088] Figure 3 This is the total ion chromatogram obtained from Q Scan. Multiple chromatographic peaks can be seen. Taking the retention time of 21.848 min as an example, the mass spectrum corresponding to this peak is... Figure 4 The mass spectrum corresponding to a retention time of 21.848 min in the total ion chromatogram obtained by Q Scan shows that the measured mass number of the target peak is 222.10. The mass spectrum can be accessed from the total ion chromatogram by double-clicking the area containing the chromatographic peak or by other methods, depending on the software settings.

[0089] Figure 5 This is the total ion chromatogram obtained from the FT Scan. Similarly, open the mass spectrum corresponding to the chromatographic peak with a retention time of 21.848 min. Figure 6 The mass spectrum corresponding to the retention time of 21.848 min in the total ion chromatogram obtained by FT Scan shows that the measured mass number of the target peak is 222.1020.

[0090] It is evident that the mass spectrum accuracy of the orbital trap FT scan is higher than that of the quadrupole Q scan. In this embodiment, the measured mass number used to calculate the mass accuracy is... Figure 6 The mass number displayed is 222.1020, while Figure 4 The displayed mass spectrum is used for NIST spectral library retrieval on the S100.

[0091] In fact, based on the rules governing the generation of the total ion chromatogram, there is always a certain time difference between each chromatographic peak on the total ion chromatogram and its time axis. On the other hand, the software automatically identifies each chromatographic peak and integrates them according to preset rules; see [link to relevant documentation]. Figure 3 Each peak in the image is labeled with its retention time; however, some peaks have missing retention times, requiring manual integration to determine their retention times. Figure 3 and Figure 5 The reason for the incomplete synchronization of retention time markers is that the selection of the integration line for chromatographic peak integration affects both retention time and peak area. If there are obvious problems with the software's automatic integration, manual re-integration is also necessary.

[0092] Similarly, for other compounds in the mixture, selecting chromatographic peaks with different retention times to open the corresponding orbital trap mass spectra allows us to obtain the measured mass numbers of those other compounds. Therefore, this invention is particularly suitable for the accurate characterization of compounds in a mixed sample. Figure 3 The retention time selected in Figure 5 If there is no perfectly corresponding retention time, it is necessary to check if there is a chromatographic peak close to that retention time, manually integrate it, and find the peak corresponding to the same or very similar retention time in the total ion chromatogram obtained by FT Scan, so as to further obtain its corresponding mass spectrum. This will not be elaborated further.

[0093] like Figure 7 As shown, NIST was used to search for compounds on the corresponding mass spectra of the Q Scan, resulting in a list of the top 10 compounds. It can be seen that the match rate of all compounds did not exceed 72%, with only 12.47% of compounds having the highest match rate and 56.56% having the highest match rate.

[0094] like Figure 8 As shown, NIST was used to search for compounds on the corresponding mass spectra from the FT Scan. The top 6 compound list shows that none of the compounds had a match rate exceeding 70%, while the probability of matching the first and second highest match rates was less than 10%.

[0095] In this embodiment, the dual verification of matching degree and probability cannot yield a qualitative result, and further information optimization and extraction through algorithms are needed. Based on the names and structural formulas matched by NIST, and according to the tightness of functional group binding, the precise mass numbers of fragment ions are calculated / estimated as shown in Table 1:

[0096] Table 1: Precise mass numbers of fragment ions

[0097]

[0098] By comparing the precise mass numbers of all major fragments with high-resolution test results, the correct compound was determined. In this example, among the precise mass numbers of fragment ions calculated based on functional groups, the theoretical mass of pyraclostrobin fragments, 222.1027 (i.e., the theoretical mass number), is... Figure 6 The precise mass of 222.1020 (i.e., the measured mass) shown in the FT Scan mass spectrum is closest to this. This confirms that the compound corresponding to this spectrum is pyraclostrobin. The selected chromatographic peak retention time is 21.848 min. According to national standards, the chromatographic peak at this retention time corresponds to pyraclostrobin, thus perfectly matching the actual compound.

[0099] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0100] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A compound qualitative identification system based on dual-mode mass spectrometry, characterized in that, It includes an ion source, a quadrupole mass spectrometer, an orbital trap mass spectrometer, and an analyzer, wherein the quadrupole mass spectrometer and the orbital trap mass spectrometer are configured to simultaneously provide their respective spectral information; The analyzer uses the quadrupole mass spectra as an index to retrieve multiple matching results from the NIST spectral library. Each matching result includes the compound name, matching degree, and probability. If a matching result exists that meets both a preset matching threshold and a preset probability threshold, then the compound name corresponding to that matching result is used as the qualitative result; otherwise, the analyzer continues to execute the following steps: The matching results are arranged from high to low according to the matching degree. The top N matching results are taken as candidate results. The theoretical mass number of the fragment ions of the corresponding candidate compounds is determined by the following method: The molecular structure formula of the candidate compound is input into the mass spectrometer data processing software. The compound fracture path is simulated according to the built-in fragmentation mechanism to predict the precise mass of the fragment ions of charged fragments generated after fracture. Here, N is an integer. The measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer. Based on the theoretical and measured mass numbers, the mass precision of each of the N candidate compounds is calculated using the following formula: Mass precision = [(Measured mass number - Theoretical mass number) / Theoretical mass number] × 10 6 ; The quality precision is selected from those that are less than or equal to the preset precision threshold. If the number of selected samples is greater than M, the selected quality precision is arranged from low to high, and the candidate compounds corresponding to the top M quality precision are retained as the qualitative results, where 0 < M ≤ N / 2.

2. The compound qualitative identification system based on dual-mode mass spectrometry analysis according to claim 1, characterized in that, A deflection focusing lens group is also provided between the quadrupole mass spectrometer and the orbital trap mass spectrometer. The quadrupole mass spectrometer includes a quadrupole, a linear ion trap, a darad electrode, and an electron multiplier. The linear ion trap is provided with an opening for lateral deflection of ions, so that a portion of the ions output from the ion source are transmitted to the darad electrode, and another portion of the ions are transmitted to the orbital trap of the orbital trap mass spectrometer after passing through the opening of the linear ion trap and the deflection focusing lens group.

3. The compound qualitative identification system based on dual-mode mass spectrometry analysis according to claim 1, characterized in that, It also includes a GC transfer line and a filament, wherein the filament is configured to heat the GC transfer line, which is configured to allow sample molecules to enter the ion source from the chromatographic column of the gas chromatograph in gaseous form.

4. The compound qualitative identification system based on dual-mode mass spectrometry analysis according to claim 1, characterized in that, Based on the spectral information provided by the orbital trap mass spectrometer, the measured mass number is determined as follows: In response to selecting a corresponding target peak in the total ion chromatogram obtained by the orbital trap mass spectrometry scan, the system generates a mass spectrum of the retention time corresponding to the target peak and displays the measured mass number of the target peak on the mass spectrum.

5. The compound qualitative identification system based on dual-mode mass spectrometry analysis according to claim 1, characterized in that, If the minimum mass precision among the N candidate compounds is greater than the precision threshold, a qualitative failure is indicated, and / or the candidate compound with the minimum mass precision is output as a reference.

6. The compound qualitative identification system based on dual-mode mass spectrometry analysis according to claim 1, characterized in that, N≤20, or N≤15, or N≤10; M=4, or M=3, or M=2, or M=1.

7. The compound qualitative identification system based on dual-mode mass spectrometry analysis according to any one of claims 1 to 6, characterized in that, The resolution of the orbital trap mass spectrometer is less than or equal to 5 ppm; The preset accuracy threshold value ranges from less than or equal to 5 ppm.

8. A method for qualitative identification of compounds based on dual-mode mass spectrometry, characterized in that, Includes the following steps: An ion source is configured to simultaneously trigger a quadrupole mass spectrometer and an orbital trap mass spectrometer, causing a portion of the ions output from the ion source to be transported to the dynamo pole of the quadrupole mass spectrometer, and causing another portion of the ions to be deflected and transported to the orbital trap of the orbital trap mass spectrometer. The quadrupole mass spectrometer generates a first spectrum, and the orbital trap mass spectrometer generates a second spectrum. Using the first spectrum as an index, multiple matching results are obtained by searching the NIST spectral library. Each matching result includes the compound name, matching degree, and probability. If a matching result exists that meets both the preset matching degree threshold and the preset probability threshold, then the compound name corresponding to that matching result is used as the qualitative result; otherwise, continue with the following steps: The matching results are arranged from high to low according to the matching degree. The top N matching results are taken as candidate results, and the theoretical mass number of the fragment ions of the corresponding candidate compounds is determined respectively: the molecular structure formula of the candidate compound is input into the mass spectrometer data processing software, and the compound fracture path is simulated according to the built-in fragmentation mechanism to predict the precise mass of the fragment ions of charged fragments generated after fracture, where N is an integer. The measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer. Based on the theoretical and measured mass numbers, the mass precision of each of the N candidate compounds is calculated using the following formula: Mass precision = [(Measured mass number - Theoretical mass number) / Theoretical mass number] × 10 6 ; The quality precision is selected from those that are less than or equal to the preset precision threshold. If the number of selected samples is greater than M, the selected quality precision is arranged from low to high, and the candidate compounds corresponding to the top M quality precision are retained as the qualitative results, where 0 < M ≤ N / 2.

9. The method for qualitative identification of compounds based on dual-mode mass spectrometry according to claim 8, characterized in that, The measured mass number is determined based on the spectral information provided by the orbital trap mass spectrometer in the following manner: in response to selecting the corresponding target peak in the total ion chromatogram obtained by the orbital trap mass spectrometer scan, a mass spectrum of the retention time corresponding to the target peak is generated, and the measured mass number of the target peak is displayed on the mass spectrum. If the minimum mass precision among the N candidate compounds is greater than the precision threshold, a qualitative failure is indicated, and / or the candidate compound with the minimum mass precision is output as a reference, wherein N≤20, or N≤15, or N≤10; M=4, or M=3, or M=2, or M=1.

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