Ion mobility spectrometry rapid scanning and spectrum correction method and device
By employing system calibration and spectral correction methods, the problem of spectral distortion under rapid scanning of FAIMS equipment was solved, enabling rapid and accurate qualitative and quantitative analysis.
Patent Information
- Application Number
- CN202310270153.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-20
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2043-03-20
AI Technical Summary
When the scanning speed of the compensation voltage is increased in existing FAIMS equipment, the spectrum is severely distorted, resulting in errors in qualitative and quantitative analysis and making it impossible to achieve rapid analysis.
The equipment parameters are obtained through system calibration, and the spectrum is obtained by combining positive and negative scanning voltages. The parameters are fitted and inverted using the FAIMS distortion peak description formula, and the distortion peak is corrected to the original Gaussian peak.
It enables accurate acquisition and correction of FAIMS spectra under rapid scanning, improves the response time and analysis efficiency of the equipment, and provides accurate qualitative and quantitative information.
Smart Images
Figure CN116359320B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of analysis algorithm of spectrum detection equipment, and particularly relates to a method and device for rapid scanning and spectrum correction of ion mobility spectrometry. BACKGROUND
[0002] High-field asymmetric ion mobility spectrometry (FAIMS) is a device that separates and detects ions in a normal pressure environment by using the difference in ion mobility at high and low fields. As shown in FIG. 1, the FAIMS analyzer is divided into an ionization zone, an analysis zone, and a detection zone. Figure 1
[0003] In the ionization zone of FAIMS, sample molecules enter the vicinity of the ionization source with the airflow, are ionized by the ionization source, and then enter the analysis zone under the driving of the airflow. In the analysis zone, the high field and the low field that alternately appear over time are constructed by the asymmetric voltage (separation voltage) to separate the ions. The mobility of the ions in the high field and the low field regions is different, so that the motion of different ions in the vertical direction is different within the time of thousands of cycles of the electric field; in the horizontal direction, all ions continuously move to the detection zone with the airflow without difference, and ions with different mobility differences show different motion paths. Due to the difference in vertical direction offset, part of the ions can directly pass through the analysis zone and enter the detection zone to be collected and detected by the collecting electrode, and then be amplified and processed by the subsequent circuit; and part of the ions are directly neutralized by hitting the electrode in the analysis zone. When only the separation voltage exists in the analysis zone, most of the ions will be neutralized in the analysis zone, and if a specific compensation voltage (CV) is applied at this time, the ions with different mobility differences can be compensated. Different compensation voltage values can make ions with different mobility differences leave the analysis zone and enter the detection zone. Therefore, the compensation voltage can be used as a scale to distinguish different ions. If a compensation voltage value that changes linearly over time is applied, ions with different mobility differences can enter the detection zone in turn to be collected and detected as the compensation voltage changes. Taking the compensation voltage as the abscissa and the detected ion intensity as the ordinate, the spectrum of FAIMS is obtained.
[0004] The response time of FAIMS is determined by the scanning speed of the compensation voltage. In order to improve the response time of FAIMS, the scanning speed of the compensation voltage is usually improved. However, simply speeding up the compensation voltage will cause serious distortion of the spectrum. A rapidly scanned spectrum and a slowly obtained spectrum have serious deviations in peak height, peak position, etc., as shown in FIG. 2. Figure 2 The FAIMS peaks exhibit symmetrical peak shape, narrow peak width and high peak height at 80s scan time. When the scan time is reduced to 4s, the FAIMS peaks exhibit broadened peak width, reduced peak height and shifted peak position. Simply increasing the compensation voltage scan speed results in serious errors in qualitative and quantitative FAIMS spectra. This is because the abscissa of FAIMS is the compensation voltage, which represents different ions and is used as the substance species (qualitative), and the ordinate is the ion intensity, which represents the number of collected ions and is used to determine the substance content (quantitative). When the peak height and peak position deviate, correct qualitative and quantitative analysis cannot be performed.
[0005] The conventional FAIMS is limited by the structure of the device itself and the characteristics of the amplification circuit, and cannot achieve fast analysis. There are a large number of analysis electrodes in the FAIMS analysis device, which form a large number of equivalent capacitors. In order to effectively detect the ion current of the sample, the FAIMS usually uses a transimpedance amplification circuit to amplify the weak electrical signal. The equivalent resistance and equivalent capacitance existing in large quantities in the FAIMS cause the shape of the ion current to change when the speed of the FAIMS ion current is too fast, and finally the FAIMS peaks presented on the spectrum are distorted. The distorted FAIMS peaks cannot extract effective qualitative and quantitative information. Therefore, in order to produce normal peaks, the scan speed of the FAIMS device cannot be set too fast. SUMMARY
[0006] The purpose of the present application is to provide a kind of ion mobility spectrum fast scanning and spectrum correction method and device, which can solve the problems in the prior art, greatly improve the scan speed of FAIMS device, and improve the overall response time of the device.
[0007] To achieve the above purpose, the following technical solutions are adopted in the present application:
[0008] In the first aspect of the present application, a kind of ion mobility spectrum fast scanning and spectrum correction method is disclosed, and the method comprises:
[0009] S1, system calibration: obtain the scan spectrum and carry out parameter fitting to determine the system parameters;
[0010] S2, fast scan spectrum acquisition: real-time spectrum acquisition, using forward scanning voltage to obtain forward scanning spectrum, and using negative scanning voltage to obtain negative scanning spectrum;
[0011] S3, spectrum correction: according to system parameters, forward scanning spectrum and negative scanning spectrum, determine the original Gaussian peak of the system, and carry out spectrum correction.
[0012] Further, the determination of system parameters and the determination of the original Gaussian peak of the system are both realized by using the description formula of the FAIMS distorted peak.
[0013] The FAIMS distortion peak description formula is:
[0014]
[0015] Wherein, I o is the output current, A is the peak height, σ is the standard deviation, p is the peak position, x is equal to CV, c is the equivalent capacitance of the system, r is the equivalent resistance of the system, k is the scan speed, e is the natural base, and Erfc is the residual function.
[0016] Further, the system calibration comprises:
[0017] The scan spectrum with a scan speed of k1 and a scan time length of T1 is obtained, and according to the system hardware conditions, the typical value of k1 should be less than 1V / s, and the corresponding scan time length T1>60s.
[0018] According to the scan spectrum, the system parameters required for subsequent correction are determined by fitting the FAIMS distortion peak description formula.
[0019] The system parameters required for subsequent correction are calibrated.
[0020] Further, the system parameters required for subsequent correction are determined by fitting the FAIMS distortion peak description formula according to the scan spectrum, comprising:
[0021] The Levenberg-Marquardt method is used to fit the FAIMS distortion peak description formula, the system parameters to be solved are randomly initialized, the random parameters are determined, the random parameters are the equivalent capacitance c of the system, the equivalent resistance r of the system, the scan speed k, the peak height A, the peak position p, and the standard deviation σ; the difference between the function image of the FAIMS distortion peak description and the actual spectrum under the condition of the random parameters is calculated, and the value of the parameter to be solved is adjusted according to the difference; repeat the above steps to obtain the calculation difference and adjust the parameters until a group of parameters are found, so that the error between the corresponding FAIMS distortion peak and the actual spectrum under the group of parameters is within the set error range, thus all the system parameters are obtained through the fitting process, and the parameters required for subsequent correction are extracted from the system parameters, and the calibration step is completed. The system parameters required for subsequent correction include the parameters cr describing the product of the equivalent resistance and the equivalent capacitance of the system and the standard deviation σ of the system Gaussian peak.
[0022] The system calibration step is used to fit the equivalent cr and the sigma of the Gaussian peak of the whole system during the equipment assembly and debugging stage. The system calibration needs to be completed only once under the condition that the general equipment hardware does not change. The system calibration process is divided into two steps: obtaining a long-time scanning spectrum and a parameter fitting process. Through the long-time scanning spectrum, the system hardware parameters are as accurately as possible, and the scanning speed k1 is recorded. The obtained long-time scanning spectrum is fitted using the description formula of the FAIMS distortion peak to obtain the cr and sigma in the description formula of the FAIMS distortion peak. This step is generally completed when the equipment is shipped. In order to more accurately obtain the cr and sigma parameters of the system, a longer scanning time should be used to obtain a more standard FAIMS spectrum, and using a FAIMS spectrum close to the standard FAIMS spectrum helps to obtain accurate cr and sigma values.
[0023] Further, the fast scanning spectrum acquisition includes:
[0024] The scanning speed k2 is used to obtain the spectrum in real time, the forward scanning voltage is used to obtain the forward scanning spectrum, and the negative scanning voltage is used to obtain the negative scanning spectrum.
[0025] The scanning speed k2 is greater than 5V / s.
[0026] This step is the step of obtaining the spectrum in real time. The spectrum is obtained in real time using a faster speed. The spectrum obtained in this step is obviously deformed, and the forward scanning CV and the negative scanning CV are used to obtain the positive and negative two spectra. The scanning speed k2 is recorded.
[0027] Further, the spectrum correction includes:
[0028] According to the forward scanning spectrum and the negative scanning spectrum, the peak position p of the original Gaussian peak of the system is determined.
[0029] According to the system parameters, the peak position p and the peak height parameter A of the original Gaussian peak of the system are determined.
[0030] According to the system parameters, the peak position p and the peak height parameter A, the original Gaussian peak of the system is determined, and the spectrum correction is performed.
[0031] Further, the expression of the original Gaussian peak of the system is:
[0032]
[0033] This step is to obtain the distorted spectrum using the fast scan spectrum of step S2, and the process of solving the original Gaussian peak by inversion algorithm. The symmetry of the positive and negative scan spectrum obtained by step S2 can be used to solve the peak position p of the original Gaussian peak, and the cr and sigma parameters obtained by step S1 system calibration, combined with the description formula of FAIMS distorted peak, the peak height parameter A of the original Gaussian peak can be obtained. According to the obtained sigma, p and peak height A, the complete expression of the original Gaussian peak can be obtained:
[0034]
[0035] Through the above algorithm, the FAIMS spectrum can be obtained and corrected in any short time using a faster scanning speed. If multiple scans are needed, repeating steps S2 and S3 can obtain multiple FAIMS fast scan spectra.
[0036] In the second aspect of the present application, a kind of ion mobility spectrum fast scanning and spectrum correction device is disclosed, and the device comprises:
[0037] System calibration module, for obtaining scanning spectrum and parameter fitting, determine system parameters;
[0038] Fast scan spectrum acquisition module, for real-time spectrum acquisition, using forward scanning voltage to obtain forward scanning spectrum, using negative scanning voltage to obtain negative scanning spectrum;
[0039] Spectrum correction module, for determining the original Gaussian peak of the system according to the system parameters, forward scanning spectrum and negative scanning spectrum, and correcting the spectrum.
[0040] Compared with the prior art, the advantages of the present application are:
[0041] The present application provides a kind of ion mobility spectrum fast scanning and spectrum correction method and device, which can obtain basic information of equipment by pre-calibration of equipment, and then obtain distorted spectrum using fast scanning method;Combining the parameter data obtained by calibration, the distorted peak obtained by fast scanning and the algorithm provided by the present application, the original FAIMS peak information can be inverted.The correction method provided by the present application solves the problem of FAIMS peak distortion under fast scanning, and through the calibration and correction process, the distorted FAIMS spectrum of fast scanning can also restore the standard peak appearance and present correct qualitative and quantitative information after the processing of the present method, which provides the possibility for real-time fast detection of ion mobility spectrum. BRIEF DESCRIPTION OF DRAWINGS
[0042] Figure 1 It is the principle diagram of FAIMS analyzer;
[0043] Figure 2is a comparison chart of the spectrum of fast scanning and the spectrum of slow scanning;
[0044] Figure 3 is a structural diagram of the FAIMS system;
[0045] Figure 4 is a first-order equivalent circuit of the FAIMS system;
[0046] Figure 5 is a flow chart of the ion mobility spectrometry fast scanning and spectrum correction method in the application;
[0047] Figure 6 is a spectrum obtained in the system calibration process;
[0048] Figure 7 is a spectrum obtained in the fast scanning spectrum acquisition process;
[0049] Figure 8 is a spectrum of the inverted Gaussian peak and the distorted Gaussian peak;
[0050] Figure 9 is a comparison chart of the Gaussian peak obtained by the traditional method, the Gaussian peak corrected by the application, and the original Gaussian peak;
[0051] Figure 10 is a block diagram of the ion mobility spectrometry fast scanning and spectrum correction device in the application. DETAILED DESCRIPTION
[0052] The application will be further described below in combination with the drawings:
[0053] In the prior art, FAIMS cannot improve the response time of the device by simply increasing the compensation voltage scanning speed. Simply increasing the scanning speed will cause serious distortion of the FAIMS peak, resulting in incorrect qualitative and quantitative analysis. The application provides an ion mobility spectrometry fast scanning and spectrum correction method. The method can obtain basic information of the device by pre-calibrating the device, and then obtain a distorted spectrum by using fast scanning. In combination with the parameter data obtained by calibration, the distorted peak obtained by fast scanning, and the algorithm provided by the application, the original FAIMS peak information can be inverted.
[0054] As shown in the FAIMS system schematic diagram, Figure 3 The sample passes through the FAIMS flat plate analyzer 3 from left to right. The sample molecules are first ionized into ions under the action of the ionization source 5. The ionized sample passes through the alternating electric field region composed of the positive and negative scanning voltages 1 and the separation voltage 4 under the action of the gas flow. Under the action of the two voltages, the ions are separated, and the separated ions enter the detection region. Under the action of the deflection voltage 6, all the ions are deflected to the electrode of the amplification circuit 2 to be collected and amplified to form a spectrum.
[0055] AsFigure 4 As shown, the FAIMS system can be represented by a capacitor C and a resistor R. The sample is ionized in the ionization region, forming ions. These ions, which are assumed to follow a Gaussian distribution, enter the analysis region and are collected in the detection region, where they are amplified by an amplifier circuit and post-processed.
[0056] The derivation of the equation describing the FAIMS distortion peak is as follows:
[0057] The input ion current is equal to the sum of the ion current flowing through the resistor and the current flowing through the capacitor:
[0058]
[0059] where R is the equivalent resistance, C is the equivalent capacitance, I o is the output current, I in is the input current.
[0060] The input ion current I in follows a Gaussian distribution and is represented as:
[0061]
[0062] where A is the peak height, σ is the standard deviation, p is the peak position, and x is the CV.
[0063] Substituting equation (2) into equation (1) gives:
[0064]
[0065] Expressing x as CV, x is linearly related to time:
[0066] x = kt (4)
[0067] Solving the differential equation gives:
[0068]
[0069] Thus, the equation describing the FAIMS distortion peak is obtained.
[0070] where I o is the output current, A is the peak height, σ is the standard deviation, p is the peak position, x is equal to CV, c is the equivalent capacitance of the system, r is the equivalent resistance of the system, k is the scan speed, e is the natural base, and Erfc is the complementary error function.
[0071] In order to correct the FAIMS spectrum obtained by fast scanning, the following three steps are included: system calibration, fast-scan spectrum acquisition, and spectrum correction.
[0072] S1. System calibration
[0073] System calibration step is a device assembly debugging stage, the equivalent cr and Gaussian peak of the whole system is fitted. Generally, the device hardware does not change, only need to complete a system calibration. System calibration process is divided into two steps: obtaining long time scanning spectrum and parameter fitting process. Through the long time scanning spectrum, the system hardware parameters are as accurately as possible, and the scanning speed k1 is recorded. The obtained long time scanning spectrum is fitted using the description formula of FAIMS distortion peak, and the cr and σ in the description formula of FAIMS distortion peak are obtained. This step is generally completed when the device is shipped, in order to more accurately obtain the cr and σ parameters of the system, a longer scanning time should be used to obtain a more standard FAIMS spectrum, and using a FAIMS spectrum close to the standard FAIMS spectrum is helpful to obtain accurate cr and σ values. According to the system hardware conditions, the typical value of k1 should be less than 1V / s, and the length of the corresponding scanning time T1>60s.
[0074] S2, fast scanning spectrum acquisition
[0075] This step is a step of obtaining a real-time fast scanning spectrum on site. A spectrum is obtained in real time using a faster speed, and generally the spectrum obtained in this step is obviously deformed, and a positive scanning CV and a negative scanning CV are needed to obtain a positive and negative spectrum, and the scanning speed k2 is recorded, k2>5V / s. The present application can obtain a group of symmetrical spectra by the positive and negative scanning method, and the accurate peak position p of the original Gaussian peak can be solved through the group of symmetrical spectra.
[0076] S3, spectrum correction
[0077] This step is a process of solving the original Gaussian peak by inversion algorithm using the distorted spectrum obtained in the second step. The symmetry of the positive and negative scanning spectra obtained in the second step can be used to solve the peak position p of the original Gaussian peak, and the peak height parameter A of the original Gaussian peak can be obtained by combining the cr and σ parameters obtained in the first step system calibration and the description formula of FAIMS distortion peak. According to the obtained σ, p and peak height A, the complete expression of the original Gaussian peak can be obtained:
[0078]
[0079] Through the above algorithm, a faster scanning speed can be used, and theoretically, FAIMS spectrum can be obtained and corrected in any short time. If multiple scanning is needed, the fast scanning spectrum acquisition (step S2) and spectrum correction (step S3) can be repeated to obtain multiple FAIMS fast scanning spectra.
[0080] The method and device of the present application will be described in detail below with reference to specific embodiments.
[0081] A ion mobility spectrometry rapid scanning and spectrum correction method, comprising the following steps:
[0082] S1, system calibration
[0083] Set the scanning speed k1=0.2, the corresponding time is about 300 seconds, obtain a slow scanning spectrum as shown in Figure 6 The slow scanning spectrum is shown in the figure, and the system is accurately calibrated using the spectrum.
[0084] The above spectrum is fitted using the description formula of FAIMS distortion peak, and the system calibration parameters σ, cr are obtained. The system parameters obtained by the system fitting step are shown in Table 1:
[0085] Table 1
[0086] Parameter Value σ 1.00058 cr x k1 0.19657 cr 0.98285
[0087] S2, fast scanning spectrum acquisition
[0088] Set the scanning speed k2=5.3, and obtain a fast scanning spectrum in the form of scanning voltage positive and negative scanning as shown in Figure 7 The spectrum acquisition time is 22.64s. The spectrum obtained here includes positive and negative scanning spectra.
[0089] The positive and negative scanning voltages are both a changing DC voltage. The positive scanning voltage is usually a linearly changing DC voltage from-30V to +30V, and the negative scanning voltage is usually a linearly changing DC voltage from +30V to-30V. This part of the voltage is controlled by the host chip of the upper computer, and is connected to the separation zone through wires after the voltage value meets the requirements through the amplification and rectification circuit.
[0090] S3, spectrum correction
[0091] The symmetry of the positive and negative spectra obtained by step S2 is solved, and the system parameters obtained by step S1 and the description formula of FAIMS distortion peak are used to fit the spectrum, and the peak height A=0.986 of the Gaussian peak is solved.
[0092] At this point, all the parameter information of the Gaussian peak is obtained as shown in Table 2.
[0093] Table 2
[0094] Parameter Value σ 1.00058 p 0 a 0.986
[0095] The inverted Gaussian peak and the distortion Gaussian peak obtained by fast scanning are drawn according to the above parameters as shown in Figure 8
[0096] If multiple spectrum information needs to be obtained, steps S2 and S3 can be repeated.
[0097] The time and error of obtaining accurate spectrum by traditional method is compared with the present method as follows Figure 9 and shown in Table 3:
[0098] Table 3
[0099] Parameter The present method The conventional method σ error 0.005 0.018 P error 0 0.196 A error 0.014 0.019 Scan time 22.64s 300s
[0100] Compared with the traditional method, the present application improves the scanning speed by nearly 10 times on the basis of obtaining more accurate peak height (A) and peak position (p) data.
[0101] As shown in Figure 10 The present application also includes a rapid scanning and spectrum correction device for ion mobility spectrometry, which comprises:
[0102] A system calibration module for obtaining a scanning spectrum and performing parameter fitting to determine system parameters;
[0103] A fast scanning spectrum acquisition module for obtaining a spectrum in real time, obtaining a forward scanning spectrum by using a forward scanning voltage and obtaining a negative scanning spectrum by using a negative scanning voltage;
[0104] A spectrum correction module for determining original Gaussian peaks of the system according to the system parameters, the forward scanning spectrum and the negative scanning spectrum, and performing spectrum correction.
[0105] In summary, the present application can obtain basic information of the equipment by pre-calibrating the equipment, and obtain a distorted spectrum by using a rapid scanning method. Combined with the parameter data obtained by calibration, the distorted peaks obtained by rapid scanning and the algorithm provided by the present application, the original FAIMS peak information can be inverted.
[0106] The above-described embodiments merely describe the preferred embodiments of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope of the present application as defined by the claims.
Claims
1. A method for rapid scanning and spectral correction of ion mobility spectra, characterized in that, The method includes: S1. System calibration: Obtain the scan spectrum and perform parameter fitting to determine the system parameters; S2. Fast scan spectrum acquisition: Real-time acquisition of spectrum, using positive scan voltage to acquire positive scan spectrum, and using negative scan voltage to acquire negative scan spectrum; S3. Spectrum Correction: Based on the system parameters, the positive scan spectrum, and the negative scan spectrum, determine the original Gaussian peak of the system and perform spectrum correction. The determination of system parameters and the determination of the original Gaussian peak of the system are both achieved using the FAIMS distortion peak description formula; The formula describing the FAIMS distortion peak is as follows: Among them, I o σ is the output current, A is the peak height, σ is the standard deviation, p is the peak position, x equals CV, c is the equivalent capacitance of the system, r is the equivalent resistance of the system, k is the scan speed, e is the natural base, and Erfc is the residual function.
2. The method according to claim 1, characterized in that, The system calibration includes: Acquire a scan spectrum with a scan speed of k1 and a scan time of T1; based on the system hardware conditions, the value of k1 is less than 1V / s, and the corresponding scan time T1 is greater than 60s; Based on the scanned spectrum, parameters are fitted, and the system parameters required for subsequent correction are determined using the FAIMS distortion peak description formula. The system parameters required for the subsequent corrections are used for calibration.
3. The method according to claim 1, characterized in that, The fast scan spectrum acquisition includes: The spectrum is acquired in real time using a scanning speed k2. A positive scanning voltage is used to acquire a positive scanning spectrum, and a negative scanning voltage is used to acquire a negative scanning spectrum.
4. The method according to claim 1, characterized in that, The spectral correction includes: Based on the positive scan spectrum and the negative scan spectrum, determine the peak position p of the original Gaussian peak of the system; Based on the system parameters, the peak height parameter A of the original Gaussian peak of the system is determined using the description formula of the FAIMS distortion peak. Based on the system parameters, peak position, and peak height parameters, the original Gaussian peak of the system is determined, and the spectrum is corrected.
5. The method according to claim 4, characterized in that, The expression for the original Gaussian peak of the system is:
6. The method according to claim 3, characterized in that, The value of the scanning speed k2 is in the range of k2>5V / s.
7. The method according to claim 4, characterized in that, The step of fitting parameters based on the scanned spectrum and determining the system parameters required for subsequent correction using the FAIMS distortion peak description formula includes: The Levenburg-Marquardt method is used to fit the descriptive formula of the FAIMS distortion peak. The system parameters to be solved are randomly initialized, and random parameters are determined, including the system's equivalent capacitance c, equivalent resistance r, scan speed k, peak height A, peak position p, and standard deviation σ. The difference between the function image describing the FAIMS distortion peak and the actual spectrum under these random parameters is calculated, and the values of the parameters to be solved are adjusted based on the difference. The above steps are repeated to obtain the calculated difference and adjust the parameters until a set of parameters is found such that the error between the corresponding FAIMS distortion peak and the actual spectrum is within a set error range. Thus, all system parameters are obtained through the fitting process. The parameters required for subsequent corrections are extracted from the system parameters, completing the calibration step.
8. The method according to claim 7, characterized in that, The system parameters required for the subsequent corrections include the parameter cr, which describes the product of the system's equivalent resistance and equivalent capacitance, and the standard deviation σ of the system's Gaussian peak.
9. A device for rapid scanning and spectral correction of ion mobility spectra, characterized in that, The device includes: The system calibration module is used to acquire scanned spectra and perform parameter fitting to determine system parameters. The fast scan spectrum acquisition module is used to acquire spectra in real time. It uses a positive scan voltage to acquire a positive scan spectrum and a negative scan voltage to acquire a negative scan spectrum. The spectrum correction module is used to determine the original Gaussian peak of the system based on system parameters, positive scan spectrum, and negative scan spectrum, and to perform spectrum correction. The determination of system parameters and the determination of the original Gaussian peak of the system are both achieved using the FAIMS distortion peak description formula; The formula describing the FAIMS distortion peak is as follows: Among them, I o σ is the output current, A is the peak height, σ is the standard deviation, p is the peak position, x equals CV, c is the equivalent capacitance of the system, r is the equivalent resistance of the system, k is the scan speed, e is the natural base, and Erfc is the residual function.