Mass spectrum method for measuring low-carbon components and low-carbon component measuring system

Abstract

The invention belongs to the technical field of column chromatography, and particularly relates to a mass spectrometry method for measuring low-carbon components and a low-carbon component measuring system.The mass spectrometry method for measuring the low-carbon components comprises the steps that components in a sample are separated into a plurality of chromatographic peak sets; acquiring a mass spectrum corresponding to each chromatographic peak group, and purifying characteristic ion peaks in each mass spectrum; reconstructing the characteristic ion peak corresponding to each component so as to carry out deconvolution on the mass spectrum; identifying substances corresponding to the components; according to the method, the detection time can be shortened, the rapid detection requirement can be met, meanwhile, by purifying the characteristic ion peak, background interference ions can be effectively removed, the definition and the signal-to-noise ratio of a mass spectrum are remarkably improved, the purified mass spectrum data are more suitable for efficient spectrum library retrieval and quantitative analysis, and by combining characteristic ion reconstruction and a deconvolution algorithm, the detection efficiency is improved. Multiple components can be accurately distinguished in a complex spectrogram, the qualitative accuracy is high, the quantitative error is low, and the reliability of a result is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of testing technology, and specifically relates to column chromatography, and in particular to a mass spectrometry method for measuring low-carbon components and a low-carbon component measurement system. Background Art

[0002] In the fields of chemical industry, environment, medicine, etc., the detection of low-carbon components (C1-C10) is an important analytical content. Traditional gas chromatography (GC) or mass spectrometry (MS) methods often require a long period of component separation before identification, and inevitably introduce some ion source pollutants, making it difficult to achieve rapid and accurate identification. In addition, in complex samples, matrix interference often affects the resolution, resulting in reduced quantitative and qualitative accuracy.

[0003] Based on gas chromatography-mass spectrometry (GC-MS), the sample needs to be purified or diluted before being injected into the system. It passes through a gas chromatography column and uses the interaction between the stationary phase and the mobile phase in the column to separate the components according to their boiling points or polarity differences. The low-boiling point components (such as C1-C5) are eluted first, and the high-boiling point components (such as C6-C10) are eluted later. The separated components enter the ion source of the mass spectrometer and are ionized to produce charged fragment ions. The mass spectrometer detects and characterizes the ions based on their mass-to-charge ratio (m / z). However, there are disadvantages such as long separation time and significant matrix interference. The sample needs to be completely chromatographically separated, which takes several minutes and is difficult to meet the needs of rapid detection. In complex samples, the high concentration of matrix components interferes with the signal of the target substance, resulting in reduced accuracy of the test results.

[0004] Direct mass spectrometry analysis technology is used. Although separation is not required, it directly enters the ion source through an injection device (such as an electrospray capillary). The sample molecules are ionized by corona discharge under atmospheric pressure to form positive and negative ions. The ions enter the mass spectrometer and are separated and detected according to the mass-to-charge ratio (m / z). The mass spectrometry signal is directly collected, and the ion fragment information is analyzed by algorithms to achieve qualitative and quantitative analysis of the compound. However, there are disadvantages such as complex spectra, severe overlap, and limited quantitative ability. When there is a lack of separation steps, the characteristic ions of different components overlap a lot, resulting in inaccurate analysis. In the absence of separation, the background ions of the complex matrix will affect the peak area determination of the target substance and reduce the accuracy of quantitative analysis.

[0005] Therefore, it is urgent to develop a new mass spectrometry method and low-carbon component measurement system to solve the technical problems of how to overcome the long chromatographic separation time and the overlap of characteristic ion signals.

[0006] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0007] The embodiments of the present disclosure at least provide a mass spectrometry method for measuring low-carbon components and a low-carbon component measurement system.

[0008] In a first aspect, an embodiment of the present disclosure provides a mass spectrometry method for measuring low-carbon components, which includes: separating the components in a sample into a plurality of chromatographic peak groups; obtaining a mass spectrum corresponding to each chromatographic peak group, and purifying characteristic ion peaks in each mass spectrum; reconstructing the characteristic ion peaks corresponding to each component to deconvolute the mass spectrum; searching the mass spectrum through the NIST library and the characteristic ion library to identify the substance corresponding to each component.

[0009] In an optional embodiment, the method for separating components in a sample into several chromatographic peak groups includes: the sample is divided into three chromatographic peak groups after separation by a chromatographic column, namely a first chromatographic peak group, a second chromatographic peak group, and a third chromatographic peak group; the first chromatographic peak group includes C1-C5 components, the second chromatographic peak group includes C6-C8 components, and the third chromatographic peak group includes C9-C10 components.

[0010] In an optional embodiment, the method for obtaining a mass spectrum corresponding to each chromatographic peak group and purifying characteristic ion peaks in each mass spectrum includes: obtaining mass spectra corresponding to the first chromatographic peak group, the second chromatographic peak group, and the third chromatographic peak group through a mass spectrometer; after removing noise peaks in the mass spectrum, obtaining model peaks in the mass spectrum; and purifying each characteristic ion peak in the mass spectrum according to the model peaks.

[0011] In an optional embodiment, the maximum peak height of the chromatographic peak in the mass spectrum is located, and a number of points are continuously scanned on both sides of the maximum peak height, and the number of scanning points is the window width; the minimum value in each scanning point is obtained, and the position corresponding to the scanning point is the boundary of the scanning window; the minimum values ​​on both sides of the maximum value in the scanning window are connected to form a baseline; a least squares fitting calculation is performed on the scanning point closest to the baseline, and the number of points used for the calculation is half of the number of window points; when the height from the maximum peak intensity point to the least squares baseline is less than a first preset threshold value, the peak is discarded.

[0012] In an optional embodiment, the maximum scanning point of the chromatographic peak and its two adjacent scanning points are obtained; a quadratic fit is performed on the maximum scanning point and its two adjacent scanning points to obtain the maximum value of the quadratic fitting curve, and the corresponding maximum retention time is obtained; all scanning points in the scanning window of the chromatographic peak are time-shifted to the left, and the shift amount is the maximum retention time and the intensity remains unchanged.

[0013] In an optional embodiment, the intensity value of the peak with the highest intensity in the chromatogram is A max , the intensity value A of the spectrum peak and the scanning points n away from the spectrum peak nThe sharpness between is positioned as: ; Among them, N f is the noise factor; each scanning time interval is divided into 10 sub-time periods; each mean sharpness corresponding to the retention time is placed in the corresponding sub-time period; the range of the sub-time period corresponding to the maximum value scanning point is obtained, and when the average sharpness corresponding to the range is the largest, the spectrum peak is the model peak.

[0014] In an optional embodiment, the mass spectrum of each ion is matched with the model peak of the measured target component, and the matching formula is: ; Where A(n) is the intensity response of the mass spectrum of each ion at scanning point n; M(n) is the intensity response of the model peak at scanning point n; a, b, and c are constants.

[0015] In an optional implementation, according to the least squares principle, the error: ; The minimum conditions are: ; to obtain the values ​​of a, b, and c, and the value of c is the intensity of the peak.

[0016] In an optional embodiment, the method of reconstructing the characteristic ion peaks corresponding to each component to deconvolve the mass spectrum includes: separating the overlapping signals between the characteristic ion peaks by proposing a model to complete the deconvolution of the mass spectrum.

[0017] In the second aspect, the embodiments of the present disclosure also provide a low-carbon component measurement system, which includes: a chromatographic column, a mass spectrometer and a host computer; the chromatographic column separates the components in the sample to separate them into a number of chromatographic peak groups; the mass spectrometer obtains a mass spectrum corresponding to each chromatographic peak group; the host computer is configured to purify the characteristic ion peaks in each mass spectrum; the host computer is configured to reconstruct the characteristic ion peaks corresponding to each component to deconvolute the mass spectrum; the host computer is configured to retrieve the mass spectrum through the NIST library and the characteristic ion library to identify the substance corresponding to each component.

[0018] The beneficial effect of the present invention is that the present invention can shorten the detection time and meet the needs of rapid detection by initially separating and screening the samples at the same time, and can effectively remove background interfering ions by purifying characteristic ion peaks, significantly improving the clarity and signal-to-noise ratio of the mass spectrum, making the purified mass spectrum data more suitable for efficient library retrieval and quantitative analysis, and combining characteristic ion reconstruction with deconvolution algorithms, it can accurately distinguish multiple components in complex spectra, with high qualitative accuracy and low quantitative error, significantly improving the reliability of the results.

[0019] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, this article specifically cites preferred embodiments and provides detailed descriptions as follows in conjunction with the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A flow chart of a mass spectrometry method for measuring low-carbon components provided in an embodiment of the present disclosure; Figure 2 A chromatogram of a total ion flow of C1-C10 provided in an embodiment of the present disclosure; Figure 3 A mass spectrum of each component provided in an embodiment of the present disclosure; Figure 4 A flowchart for removing noise spectrum peaks provided in an embodiment of the present disclosure; Figure 5 A flowchart of peak sharpness determination provided in an embodiment of the present disclosure; Figure 6 A vector representation diagram of a three-dimensional space of a graph provided in an embodiment of the present disclosure; Figure 7 A principle block diagram of a low-carbon component measurement system provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In this article, when it is mentioned that the first component is located on the second component, this may mean that the first component may be directly formed on the second component, or the third component may be interposed between the first component and the second component. In addition, in the drawings, in order to effectively describe the technical content, the thickness of the components may be exaggerated or reduced.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0027] like Figures 1 to 6 At least one embodiment provides a mass spectrometry method for measuring low-carbon components, which includes: separating the components in the sample to separate them into a number of chromatographic peak groups; obtaining a mass spectrum corresponding to each chromatographic peak group, and purifying the characteristic ion peaks in each mass spectrum; reconstructing the characteristic ion peaks corresponding to each component to deconvolute the mass spectrum; searching the mass spectrum through the NIST library and the characteristic ion library to identify the substance corresponding to each component.

[0028] Specifically, the full name of NIST refers to the National Institute of Standards and Technology, and the NIST library is a large commercial mass spectrometry database that provides a large number of mass spectra and related data.

[0029] In at least one embodiment, by initially separating and screening the sample at the same time, the detection time can be shortened to meet the needs of rapid detection. At the same time, by purifying the characteristic ion peaks, the background interfering ions can be effectively removed, and the clarity and signal-to-noise ratio of the mass spectrum can be significantly improved, making the purified mass spectrometry data more suitable for efficient library retrieval and quantitative analysis. In addition, by combining the characteristic ion reconstruction and deconvolution algorithm, multiple components can be accurately distinguished in complex spectra, with high qualitative accuracy and low quantitative error, thereby significantly improving the reliability of the results.

[0030] In at least one embodiment, see Figure 2 The method for separating the components in the sample into several chromatographic peak groups includes: the sample is divided into three chromatographic peak groups after separation by a chromatographic column, namely a first chromatographic peak group, a second chromatographic peak group, and a third chromatographic peak group; the first chromatographic peak group includes C1-C5 components, the second chromatographic peak group includes C6-C8 components, and the third chromatographic peak group includes C9-C10 components.

[0031] Specifically, the first chromatographic peak group (C1-C5): Under appropriate temperature control conditions, the chromatographic column can complete the separation of C1-C5 components within 25 seconds, mainly including methane, ethane, propane, butane and pentane. These components have small molecular weights and low boiling points, so they can pass through the chromatographic column quickly after temperature control optimization.

[0032] Specifically, the second chromatographic peak group (C6-C8): under further heating conditions, n-hexane, n-heptane and n-octane are separated within 30 seconds. The components of this peak group have slightly higher boiling points and molecular weights, ensuring that unique chromatographic peaks can be formed in the chromatographic column, which is convenient for mass spectrometry detection.

[0033] Specifically, the third chromatographic peak group (C9-C10): under the highest temperature conditions, benzene, toluene, n-nonane and n-decane were separated and the peak group detection was completed within 40 seconds.

[0034] Specifically, the three separated chromatographic peak groups represent three typical boiling point ranges of low-carbon components, which simplifies the mass spectrometry detection process while avoiding interference from complex matrices.

[0035] Specifically, after the chromatographic peak groups are separated, the detection time window of each group is locked, and the ions within the target peak group are limited for screening to avoid interference from non-target components. A standard characteristic ion library is established for low-carbon components, and 1-3 characteristic ion peaks (such as m / z 86, 57, and 43 for C6) are selected for each component for rapid identification. When performing mass spectrometry retrieval, the characteristic ion peaks of each component are automatically extracted from the complex spectrum to form a characteristic spectrum and achieve rapid identification within 30 seconds.

[0036] Specifically, see Figure 3 , Figure 3 The upper left in the middle is n-hexane (m / z 86), the upper right is n-heptane (m / z 100), the lower left is methylcyclohexane (m / z 98), and the lower right is benzene (m / z 78). In at least one embodiment, the method for obtaining a mass spectrum corresponding to each chromatographic peak group and purifying characteristic ion peaks in each mass spectrum includes: obtaining mass spectra corresponding to the first chromatographic peak group, the second chromatographic peak group, and the third chromatographic peak group through a mass spectrometer; after removing noise peaks in the mass spectrum, obtaining model peaks in the mass spectrum; and purifying each characteristic ion peak in the mass spectrum according to the model peaks.

[0037] In at least one embodiment, see Figure 4 , Figure 5, locate the maximum peak height of the chromatographic peak in the mass spectrum, and continuously scan a number of points on both sides of the maximum peak height, and the number of scanning points is the window width; obtain the minimum value in each scanning point, and the position corresponding to the scanning point is the boundary of the scanning window; connect the minimum values ​​on both sides of the maximum value in the scanning window to form a baseline; perform a least squares fitting calculation on the scanning point closest to the baseline, and the number of points used for the calculation is half of the number of window points; when the height from the maximum peak intensity point to the least squares baseline is less than the first preset threshold, the peak is discarded.

[0038] Specifically, when the height from the maximum peak intensity point to the least squares baseline is greater than a first preset threshold, the peak is recorded and considered to be a possible component.

[0039] In at least one embodiment, the maximum scanning point of the chromatographic peak and its two adjacent scanning points are obtained; a quadratic fit is performed on the maximum scanning point and its two adjacent scanning points to obtain the maximum value of the quadratic fitting curve, and the corresponding maximum retention time is obtained; all scanning points in the scanning window of the chromatographic peak are time-shifted to the left, and the shift amount is the maximum retention time and the intensity remains unchanged.

[0040] Specifically, find out the maximum value point of the chromatographic peak as point b, and its two adjacent points as points a and c; use the quadratic fitting method to fit the spectral peak points b, a and c, find the maximum value of the quadratic fitting curve, and find out the retention time corresponding to the maximum value, which is the maximum retention time t; correction of retention time: time-shift all scanning points in the scanning window of the chromatographic peak to the left, the shift amount is t, and the intensity remains unchanged.

[0041] In at least one embodiment, the intensity value of the peak with the highest intensity in the chromatogram is A max , the intensity value A of the spectrum peak and the scanning points n away from the spectrum peak n The sharpness between is positioned as: ; Among them, N f is the noise factor; each scanning time interval is divided into 10 sub-time periods; each mean sharpness corresponding to the retention time is placed in the corresponding sub-time period; the range of the sub-time period corresponding to the maximum value scanning point is obtained, and when the average sharpness corresponding to the range is the largest, the spectrum peak is the model peak.

[0042] Specifically, the uncertainty range of the sub-time period corresponding to the maximum value is obtained. If, within the uncertainty range, the average sharpness corresponding to no other sub-time period is greater than the average sharpness corresponding to the maximum value time period, then there is a target compound in the time period, that is, the spectral peak is the model peak.

[0043] In at least one embodiment, the mass spectrum of each ion is matched with the model peak of the measured target component, and the matching formula is: ; Where A(n) is the intensity response of the mass spectrum of each ion at scanning point n; M(n) is the intensity response of the model peak at scanning point n; a, b, and c are constants.

[0044] Specifically, a, b, and c are constants to be determined.

[0045] Specifically, a+b·n is used as the background signal, where a is the offset of the background signal and b is the slope of the background signal.

[0046] Specifically, the two constants a and b obtained represent the linear baseline of the background signal and are used for baseline subtraction.

[0047] Specifically, the matching formula represents the portion of the signal intensity that is higher than the background signal and is used for the extraction of the spectrum.

[0048] Specifically, each extracted intensity value is , n max That is, the position of the scanning point where the model peak appears to have a maximum value.

[0049] In at least one embodiment, according to the least squares principle, the error: ; The minimum conditions are: ; to obtain the values ​​of a, b, and c, and the value of c is the intensity of the peak.

[0050] Specifically, when the mass spectrum is calculated by the above formula, the mass spectrum peaks of each component can be purified. The method of the measured components has been verified by experiments, and can effectively remove background interfering ions, significantly improve the clarity and signal-to-noise ratio of the mass spectrum, and make the purified mass spectrum data more suitable for efficient library retrieval and quantitative analysis.

[0051] Specifically, the data purification technology effectively removed the ion source background noise and matrix interference, and the signal-to-noise ratio was increased to more than 3 times the original. The data purification technology based on the model peak effectively eliminated the ion source pollutants and complex matrix interference, enhanced the purity and signal-to-noise ratio of the mass spectrometry data, and provided high-quality data support for library retrieval and quantitative analysis.

[0052] In at least one embodiment, the method of reconstructing the characteristic ion peaks corresponding to each component to deconvolve the mass spectrum includes: separating the overlapping signals between the characteristic ion peaks by proposing a model to complete the deconvolution of the mass spectrum.

[0053] Specifically, by reconstructing the characteristic ion peaks of each component, accurate and rapid identification of each component in a complex spectrum is ensured. When analyzing a multi-component mixed sample, the characteristic ion peaks between components may overlap. When measuring a multi-component mixed sample, the characteristic ion peaks of each component may overlap, for example, the characteristic ion of C6 is m / z 86, and the characteristic ions of C8 are m / z 86 and 114. At this time, the signal value of m / z 86 in the test result may contain part of C6 and part of C8. At this time, the signals of the second and third characteristic ion peaks of each of the controversial components are extracted, and the chromatographic peaks with overlapping signals are separated first. By analyzing the relative intensities of other characteristic ions, the algorithm can identify which ion signals come from C6 or C8, thereby achieving rapid separation of overlapping signals.

[0054] Specifically, in the separated overlapping signals, deconvolution is performed through the characteristic ion and abundance relationship. After the overlapping signals are detected, the ion signals of the overlapping parts are first separated according to the signal abundance ratio of the second and third characteristic ion peaks in each component. Since there is always one independent characteristic ion peak among the three characteristic ion peaks of each component, that is, the peak does not overlap with the characteristic ion peaks generated by other components. Therefore, this independent characteristic ion peak can be used as a calculation basis, and its contribution to the mass intensity can be accurately calculated in combination with its abundance relationship with the first characteristic ion peak. In the deconvolution process, cross-calculations and verifications are performed between multiple characteristic ion peaks to ensure accurate distribution of the proportion of overlapping signals. The spectrum can calculate the angle between the vectors of the sample and the reference in the mass number space in a three-dimensional coordinate system, and can quickly identify the actual proportion of each group in the overlapping signal, so as to be used for identification and quantitative analysis.

[0055] Specifically, the sample space is represented by X. In the sample space X, the vector space represented by the mass number set I can be expressed as: ; Among them, W xi is the contribution of the ith mass number in the sample space.

[0056] Specifically, the reference object space is represented by Y. In the reference object space Y, the vector space represented by the mass number set I can be represented as: ; Among them, W Yi is the contribution of the ith mass number in the sample space.

[0057] Specifically, according to the above two formulas, the spectrum can be regarded as a point in a multidimensional coordinate system. This multidimensional coordinate system is composed of the mass number of the spectrum and can be represented by (I1, I2, ..., I n ) indicates that, with mass number I i The corresponding contribution W xi or W Yi This means that the point is on the coordinate axis Ii Therefore, the sample spectrum and the reference spectrum can be regarded as a point in the sample space and the reference space.

[0058] If the sample spectrum X i and reference spectrum Y i Containing the same three mass numbers I1, I2, I3, the two spectra can be represented by two vectors X and Y in a three-dimensional coordinate system, such as Figure 6 shown.

[0059] Assume that the intensity of the sample spectrum corresponding to the three mass numbers I1, I2, and I3 is H X1 ,H X2 ,H X3 The intensities of the reference spectra corresponding to these three mass numbers are H Y1 ,H Y2 ,H Y3 If there is H X1 =H Y1 ,H X2 =H Y2 ,H X3 =H Y3 Then the sample can be considered as the reference object, that is, the vector X i and vector Y i The angle between them is zero. Therefore, in the V-based spectrum retrieval algorithm, if mass spectrum retrieval calculation is to be realized, it is only necessary to calculate the angle between the vectors of the sample and the reference in the mass number space. Therefore, in the spectrum retrieval algorithm proposed in the present invention, the similarity calculation method between the sample spectrum and the reference spectrum will adopt the cosine similarity calculation method.

[0060] Calculation of similarity between spectra: The mass number set of a sample in the sample space X , intensity set , the mass number set of a reference object in the reference object space Y , intensity set .

[0061] Take sample mass number collection and the reference mass set The union of , let the union The number of elements in is u. It forms a u-dimensional mass number space X Iu . Sample and reference material spectra in X Iu The coordinates inside can be expressed as: , where i ranges from 1 to u.

[0062] Specifically, according to the above formula, we can get the mass number space X of the sample and the reference: IuThe internal coordinates can be expressed as vectors and vector According to the cosine similarity calculation, the similarity between two vectors can be obtained by the following formula: The larger the calculated sim value is, the stronger the two vectors are. and vector The more similar, the higher the similarity between the sample spectrum and the reference spectrum.

[0063] Specifically, each component is searched through the NIST library, and the search results of each component are compared with the search results of the characteristic ion library, as shown in Table 1 and Table 2. The similarity ranking of n-Hexane and toluene in the two library search results is the same as that in the characteristic ion library search, and each substance can be accurately identified.

[0064] Table 1

[0065] Table 2

[0066] Combining characteristic ion reconstruction and deconvolution algorithms, it is possible to accurately distinguish multiple components in complex spectra, with a qualitative accuracy of over 99% and a quantitative error of less than ±3%, significantly improving the reliability of the results.

[0067] Based on the same inventive concept, Figures 1 to 7 At least one embodiment further provides a low-carbon component measurement system, which includes: a chromatographic column, a mass spectrometer and a host computer; the chromatographic column separates the components in the sample to separate them into a number of chromatographic peak groups; the mass spectrometer obtains a mass spectrum corresponding to each chromatographic peak group; the host computer is configured to purify the characteristic ion peaks in each mass spectrum; the host computer is configured to reconstruct the characteristic ion peaks corresponding to each component to deconvolve the mass spectrum; the host computer is configured to retrieve the mass spectrum through the NIST library and the characteristic ion library to identify the substance corresponding to each component.

[0068] In summary, the present invention can shorten the detection time and meet the needs of rapid detection by initially separating and screening the samples. At the same time, by purifying the characteristic ion peaks, the background interfering ions can be effectively removed, and the clarity and signal-to-noise ratio of the mass spectrum can be significantly improved, making the purified mass spectrometry data more suitable for efficient library retrieval and quantitative analysis. In addition, combined with the characteristic ion reconstruction and deconvolution algorithm, it can accurately distinguish multiple components in complex spectra, with high qualitative accuracy and low quantitative error, thereby significantly improving the reliability of the results.

[0069] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0070] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, terms such as "first", "second" and other numerical terms do not imply an order or sequence when used in this document unless explicitly indicated above. Therefore, without departing from the teachings of the example embodiments, the first element, component, region, layer or section discussed above may be referred to as a second element, component, region, layer or section.

[0071] Spatially relative terms, such as "inside", "outside", "below", "below", "down", "above", "on", etc., may be used herein to facilitate description of the relationship of one element or feature to another element or feature as illustrated in the figure. In addition to the orientation depicted in the figure, spatially relative terms may be intended to cover different orientations of the device in use or operation. For example, if the device in the figure is turned over, the elements described as "below" or "below" other elements or features will be oriented to be "above" other elements or features. Therefore, the example term "below" can cover the orientation above and below. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0072] In the above discussion, unless otherwise stated, the terms "about," "approximately," "substantially," etc., when used to describe a numerical value, mean a variation of + / - 10% of the value.

[0073] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A mass spectrometry method for measuring low-carbon components, characterized in that: include: Separate the components in the sample into several chromatographic peak groups; Obtain the mass spectrum corresponding to each chromatographic peak group, and purify the characteristic ion peaks in each mass spectrum; The characteristic ion peaks corresponding to each component are reconstructed to deconvolve the mass spectrum; The mass spectra were searched through the NIST library and characteristic ion library to identify the substances corresponding to each component.

2. The mass spectrometry method for measuring low-carbon components according to claim 1, characterized in that: The method for separating the components in the sample into a plurality of chromatographic peak groups comprises: After separation by the chromatographic column, the sample is divided into three chromatographic peak groups, namely the first chromatographic peak group, the second chromatographic peak group, and the third chromatographic peak group; The first chromatographic peak group includes C1-C5 components, the second chromatographic peak group includes C6-C8 components, and the third chromatographic peak group includes C9-C10 components.

3. The mass spectrometry method for measuring low-carbon components according to claim 2, characterized in that: The method for obtaining the mass spectrum corresponding to each chromatographic peak group and purifying the characteristic ion peaks in each mass spectrum includes: Obtaining mass spectra corresponding to the first chromatographic peak group, the second chromatographic peak group, and the third chromatographic peak group by a mass spectrometer; After removing the noise peak in the mass spectrum, the model peak in the mass spectrum is obtained; Purify the characteristic ion peaks in the mass spectrum according to the model peak.

4. The mass spectrometry method for measuring low-carbon components according to claim 3, characterized in that: Locate the maximum peak height of the chromatographic peak in the mass spectrum, and continuously scan a number of points on both sides of the maximum peak height, and the number of scanning points is the window width; Get the minimum value of each scanning point, and the position corresponding to the scanning point is the boundary of the scanning window; Connect the minimum values ​​on both sides of the maximum value in the scan window to form a baseline; Perform a least squares fitting calculation on the scan point closest to the baseline, and the number of points used in the calculation is half of the number of window points; When the height from the maximum peak intensity point to the least squares baseline is less than a first preset threshold, the peak is discarded.

5. The mass spectrometry method for measuring low-carbon components according to claim 4, characterized in that: Obtain the maximum scanning point of the chromatographic peak and its two adjacent scanning points; Perform quadratic fitting on the maximum scanning point and its two adjacent scanning points to obtain the maximum value of the quadratic fitting curve and the corresponding maximum retention time; All scanning points within the scanning window of the chromatographic peak are time-shifted to the left, and the shift amount is the maximum retention time and the intensity remains unchanged.

6. The mass spectrometry method for measuring low-carbon components according to claim 5, characterized in that: The intensity of the highest peak in the chromatogram is A max , the intensity value A of the spectrum peak and the scanning points n away from the spectrum peak n The sharpness between is positioned as: ; Among them, N f is the noise factor; Each scanning time interval is divided into 10 sub-time periods; Put each mean sharpness corresponding to the retention time into the corresponding sub-time period; The range of the sub-time period corresponding to the maximum value scanning point is obtained, and when the average sharpness corresponding to the range is the largest, the spectrum peak is a model peak.

7. The mass spectrometry method for measuring low-carbon components according to claim 6, characterized in that: The mass spectrum of each ion is matched with the model peak of the measured target component, and the matching formula is: ； Where A(n) is the intensity response of the mass spectrum of each ion at scan point n; M(n) is the intensity response of the model peak at scan point n; a, b, c are constants.

8. The mass spectrometry method for measuring low-carbon components according to claim 7, characterized in that: According to the least squares principle, the error: ; The minimum conditions are: ; To obtain the values ​​of a, b, and c, where the value of c is the intensity of the peak.

9. The mass spectrometry method for measuring low-carbon components according to claim 1, characterized in that: The method of reconstructing the characteristic ion peaks corresponding to each component to deconvolute the mass spectrum includes: The proposed model is used to separate the overlapping signals between the characteristic ion peaks to complete the deconvolution of the mass spectrum.

10. A low carbon component measurement system, characterized in that: include: Chromatographic columns, mass spectrometers and host computers; The chromatographic column separates the components in the sample to separate into a number of chromatographic peak groups; The mass spectrometer obtains a mass spectrum corresponding to each chromatographic peak group; The host computer is configured to purify characteristic ion peaks in each mass spectrum; The host computer is configured to reconstruct the characteristic ion peaks corresponding to each component to deconvolve the mass spectrum; The host computer is configured to search the mass spectra through the NIST library and the characteristic ion library to identify the substances corresponding to each component.

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