Method, system, electronic device and storage medium for determining cadmium content of Panax notoginseng

Abstract

The present invention discloses a method, system, electronic device, and storage medium for determining the cadmium content of Panax notoginseng, relating to the technical field of metal content detection. The method comprises: after laser ablation of the Panax notoginseng to be detected, determining the laser-induced breakdown spectrum and shape parameters of each ablation pit to be detected on the Panax notoginseng to be detected; the shape parameters include cross-sectional area, maximum depth, perimeter, vertical Feret diameter, and surface area; determining the corrected intensity of the characteristic emission line to be detected corresponding to the ablation pit to be detected based on each laser-induced breakdown spectrum to be detected; and determining the cadmium content of the Panax notoginseng to be detected based on a fitting equation for the cadmium content of the Panax notoginseng and all shape parameters and corrected intensities of the Panax notoginseng to be detected; the fitting equation for the cadmium content of the Panax notoginseng to be detected is determined using the actual cadmium content values, shape parameters, and corrected intensities of the characteristic emission lines of multiple Panax notoginseng samples. The present invention improves the accuracy of Panax notoginseng cadmium content detection.

Description

Technical Field

[0001] The present invention relates to the technical field of metal content detection, and in particular to a method, system, electronic equipment and storage medium for determining the cadmium content of Panax notoginseng. Background Art

[0002] Panax notoginseng is a perennial herbaceous plant in the genus Panax, Araliaceae. It is a precious Chinese medicinal material and second only to ginseng in terms of its prevalence. Its product development has expanded into new food ingredients, daily necessities, and health foods. This demonstrates the immense research value and potential for its application.

[0003] To ensure the clinical safety and efficacy of traditional Chinese medicine, quality testing is crucial. Cadmium (Cd) contamination is a prominent manifestation of excessive heavy metals in Panax notoginseng. Cd ranks as the leading source of soil contamination in cultivation areas, and Panax notoginseng has a strong ability to absorb and accumulate Cd, as well as transport it to its aerial parts. Cd contamination inhibits the growth and development of Panax notoginseng, causes oxidative stress damage, reduces the accumulation of its medicinal components, diminishes its efficacy, and even poses risks to human health.

[0004] The main methods for Cd detection include atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). These methods require complex sample pretreatment, are time-consuming and labor-intensive, have high professional requirements for operators, and consume a large amount of chemical reagents during the detection process. As a result, they cannot meet the digital, networked, and intelligent detection needs of the traditional Chinese medicine industry.

[0005] Laser-induced breakdown spectroscopy (LIBS) is an atomic emission spectroscopic analysis method that uses high-energy laser pulses to directly focus on a sample, thereby inducing the generation of plasma in the sample. LIBS has the advantages of simple or even no sample pretreatment, rapid detection process, wide analytical concentration range, suitability for full element analysis, real-time analytical results, and the ability to achieve long-distance telemetry.

[0006] During LIBS signal acquisition, instrument system errors, experimental environment interference, and other factors can cause signal fluctuations, affecting test results. Plant samples, due to their complex composition and widely varying physicochemical properties, are also subject to matrix effects, presenting further challenges for LIBS detection. Summary of the Invention

[0007] The purpose of the present invention is to provide a method, system, electronic equipment and storage medium for determining the cadmium content of Panax notoginseng, thereby improving the accuracy of Panax notoginseng cadmium content detection.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] A method for determining the cadmium content of Panax notoginseng, comprising:

[0010] After laser ablation of the Panax notoginseng to be tested, determining the laser induced breakdown spectrum and shape parameters of each ablation pit to be tested on the Panax notoginseng to be tested; the shape parameters include: cross-sectional area, maximum depth, perimeter, vertical Feret diameter, and surface area;

[0011] determining the corrected intensity of the characteristic emission line to be detected corresponding to the ablation pit to be detected based on each of the laser induced breakdown spectra to be detected;

[0012] Based on the fitting equation of the cadmium content of Panax notoginseng and all the shape parameters and correction intensities of the Panax notoginseng to be tested, the cadmium content of the Panax notoginseng to be tested is determined; the fitting equation of the cadmium content of Panax notoginseng is determined using the true values ​​of the cadmium content, shape parameters and correction intensities of the characteristic emission spectra of multiple Panax notoginseng samples.

[0013] Optionally, the process of determining the fitting equation for the cadmium content of Panax notoginseng includes:

[0014] Prepare multiple Panax notoginseng samples containing cadmium;

[0015] Determine the true value of the cadmium content of each of the Panax notoginseng samples;

[0016] After laser ablation treatment is performed on each of the Panax notoginseng samples, a sample laser induced breakdown spectrum and shape parameters of each sample ablation pit on each of the Panax notoginseng samples are determined;

[0017] Determining the corrected intensity of the sample characteristic emission line corresponding to the sample ablation pit based on the laser induced breakdown spectrum of each sample;

[0018] Determining a new response value corresponding to the sample ablation crater using a multiple linear regression method based on the shape parameters of each sample ablation crater and the corrected intensity of the sample characteristic emission line;

[0019] Based on all the new response values ​​and all the true values ​​of the cadmium element content, a fitting equation for the cadmium content of Panax notoginseng is determined.

[0020] Optionally, determining the correction intensity of the characteristic emission line to be detected corresponding to the ablation pit to be detected based on each of the laser induced breakdown spectra to be detected specifically includes:

[0021] Determine the characteristic emission spectral lines to be detected corresponding to the ablation pits to be detected from each of the laser-induced breakdown spectra to be detected;

[0022] Calculate the set of intensity ratios to be detected for each of the ablation pits to be detected; the set of intensity ratios to be detected includes a plurality of intensity ratios to be detected, where the j-th intensity ratio to be detected is the ratio of the intensity of the characteristic emission spectral line to be detected to the intensity of the j-th non-characteristic emission spectral line to be detected in the laser-induced breakdown spectrum to be detected corresponding to the ablation pit to be detected; 1 < j ≤ q - 1, and q is the total number of wavelengths of the laser-induced breakdown spectrum to be detected;

[0023] Based on the set of intensity ratios to be detected for each of the ablation pits to be detected and the intensity of the characteristic emission spectral line to be detected, determine the corrected intensity of the characteristic emission spectral line to be detected corresponding to the ablation pit to be detected.

[0024] Optionally, the laser-induced breakdown spectrum to be detected is determined using a laser-induced breakdown spectroscopy detection platform.

[0025] Optionally, the shape parameter is determined using a shape measurement laser microscopy system.

[0026] Optionally, determining the corrected intensity of the characteristic emission spectral line corresponding to the sample ablation pit based on each of the sample laser-induced breakdown spectra specifically includes:

[0027] Determine the characteristic emission spectral lines corresponding to the sample ablation pits from each of the sample laser-induced breakdown spectra; <id=

[0028] Calculate the set of sample intensity ratios for each of the sample ablation pits on each of the pseudo-ginseng samples; the set of intensity ratios includes a plurality of sample intensity ratios, where the j-th sample intensity ratio is the ratio of the intensity of the characteristic emission spectral line to the intensity of the j-th non-characteristic emission spectral line in the sample laser-induced breakdown spectrum corresponding to the sample ablation pit; 1 < j ≤ p - 1, p is the total number of wavelengths of the sample laser-induced breakdown spectrum, and p = q;

[0029] Based on the set of sample intensity ratios for each of the sample ablation pits and the intensity of the characteristic emission spectral line, determine the corrected intensity of the characteristic emission spectral line corresponding to the sample ablation pit. <00.id= [[ID=2.id=0000141]]

[0030] A system for determining the cadmium element content of pseudo-ginseng, comprising:

[0031] A data acquisition module, configured to determine the laser-induced breakdown spectrum to be detected and the shape parameter of each ablation pit to be detected on the pseudo-ginseng to be detected after laser ablation treatment; the shape parameter includes: cross-sectional area, maximum depth, perimeter, vertical Feret diameter, and surface area;

[0032] a correction intensity determination module, configured to determine, based on each of the laser-induced breakdown spectra to be detected, a correction intensity of a characteristic emission line to be detected corresponding to the ablation pit to be detected;

[0033] The cadmium content determination module is used to determine the cadmium content of the Panax notoginseng to be tested based on the Panax notoginseng cadmium content fitting equation and all shape parameters and correction intensities of the Panax notoginseng to be tested; the Panax notoginseng cadmium content fitting equation is determined using the true values ​​of the cadmium content, shape parameters and correction intensities of characteristic emission spectra of multiple Panax notoginseng samples.

[0034] An electronic device, comprising:

[0035] one or more processors;

[0036] a storage device having one or more programs stored thereon;

[0037] When the one or more programs are executed by the one or more processors, the one or more processors implement the method for determining the cadmium content of Panax notoginseng as described above.

[0038] A storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for determining the cadmium content of Panax notoginseng as described above is implemented.

[0039] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0040] The present invention discloses a method, system, electronic device and storage medium for determining the cadmium content of Panax notoginseng. First, a laser induced breakdown spectrum and shape parameters of each ablation pit to be detected on the Panax notoginseng to be detected are determined. Second, a correction intensity of a characteristic emission line to be detected corresponding to the ablation pit to be detected is determined based on each laser induced breakdown spectrum to be detected. Finally, the cadmium content of the Panax notoginseng to be detected is determined based on a fitting equation for the cadmium content of Panax notoginseng and all shape parameters and correction intensities of the Panax notoginseng to be detected. By combining the shape parameters of the ablation pit with the laser induced breakdown spectrum, the accuracy of the cadmium content detection of Panax notoginseng is improved compared with using only the laser induced breakdown spectrum. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 A schematic flow chart of a method for determining the cadmium content of Panax notoginseng provided in Example 1 of the present invention;

[0043] Figure 2 Flowchart of a method for detecting the cadmium content of Panax notoginseng based on ablation crater shape compensation and characteristic peak ratio correction in a specific embodiment;

[0044] Figure 3 This is a morphology of ablation pits formed by laser ablation of a Panax notoginseng pressed tablet in a specific embodiment;

[0045] Figure 4 Schematic diagram of the position of the interfering variable in the LIBS spectrum in a specific embodiment;

[0046] Figure 5 Schematic diagram of the system structure for determining the cadmium content of Panax notoginseng provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 making creative efforts are within the scope of protection of the present invention.

[0048] The purpose of the present invention is to provide a method, system, electronic device and storage medium for determining the cadmium content of Panax notoginseng, aiming to improve the accuracy of Panax notoginseng cadmium content detection.

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1

[0051] Figure 1 Schematic diagram of the method for determining the cadmium content of Panax notoginseng provided in Example 1 of the present invention. Figure 1 As shown, the method for determining the cadmium content of Panax notoginseng in this embodiment includes:

[0052] Step 101: After the Panax notoginseng to be tested is subjected to laser ablation treatment, the laser induced breakdown spectrum and shape parameters of each ablation pit to be tested on the Panax notoginseng to be tested are determined.

[0053] Among them, shape parameters include: cross-sectional area, maximum depth, circumference, perpendicular Feret diameter and surface area.

[0054] Step 102: Determine the correction intensity of the characteristic emission line to be detected corresponding to the ablation pit to be detected based on each laser induced breakdown spectrum to be detected.

[0055] Step 103: Determine the cadmium content of the Panax notoginseng to be tested based on the fitting equation of the cadmium content of the Panax notoginseng and all shape parameters and correction intensities of the Panax notoginseng to be tested.

[0056] Among them, the fitting equation for the cadmium content of Panax notoginseng was determined using the true values ​​of the cadmium element content, shape parameters and corrected intensities of the characteristic emission spectra of multiple Panax notoginseng samples.

[0057] As an optional implementation, the process of determining the fitting equation for the cadmium content of Panax notoginseng includes:

[0058] Prepare multiple Panax notoginseng samples containing cadmium.

[0059] Determine the true value of cadmium content in each Panax notoginseng sample.

[0060] After laser ablation treatment of each Panax notoginseng sample, the sample laser induced breakdown spectrum and shape parameters of each sample ablation pit on each Panax notoginseng sample were determined.

[0061] Specifically, a laser-induced breakdown spectroscopy detection platform was used to obtain LIBS spectral data (i.e., sample laser-induced breakdown spectrum) of n collection points (i.e., ablation pits) of the Panax notoginseng sample; a shape measurement laser microscope system was used to collect and process the shape parameters of the sample ablation pits using corresponding analysis software, which included: cross-sectional area A, maximum depth D, circumference P, vertical Feret diameter F, and surface area S; and an inductively coupled plasma mass spectrometer was used to measure the actual value C of the cadmium content in the Panax notoginseng sample.

[0062] The corrected intensity of the sample characteristic emission line corresponding to the sample ablation crater is determined based on the laser induced breakdown spectrum of each sample.

[0063] The new response value of the corresponding sample ablation crater is determined by using the multivariate linear regression method based on the shape parameters of the ablation crater of each sample and the corrected intensity of the sample characteristic emission spectrum.

[0064] Specifically, the shape parameters of the ablation pits at n collection points are recorded as: cross-sectional area A n , maximum depth D n , perimeter P n , vertical Feret diameter F n , surface area S n , which is used to describe the shape characteristics of the ablation crater; the signal intensity collected by the LIBS system is obtained by ratio correction to obtain x N ' n ; and the actual value of cadmium content C n . N ' n 、A n 、D n 、P n 、F n 、Sn As an independent variable input, C n As the dependent variable output, through the multivariate linear regression method analysis, the weighted regression coefficients (Beta coefficients, β) reflecting the importance of each independent variable are obtained. β is used as the coefficient of the corresponding independent variable, and a new response value R is constructed as the vertical coordinate value. A calibration curve model based on the new response value is established as follows:

[0065] R=β1x N ' n +β2A n +β3D n +β4P n +β5F n +β6S n

[0066] Among them, β1, β2, β3, β4, β5, and β6 are the weighted regression coefficients corresponding to the input independent variables.

[0067] Based on all new response values ​​and the true values ​​of all cadmium element contents, the fitting equation for the cadmium content in Panax notoginseng was determined.

[0068] Specifically, a calibration curve was drawn with the cadmium content of the sample Panax notoginseng as the horizontal coordinate and the new response value as the vertical coordinate to obtain a linear fitting equation for detecting the cadmium content of Panax notoginseng.

[0069] As an optional implementation, step 102 specifically includes:

[0070] The characteristic emission lines to be detected corresponding to the ablation pits to be detected are determined from each laser induced breakdown spectrum to be detected.

[0071] Specifically, according to the atomic spectrum database of the National Institute of Standards and Technology (NIST), the characteristic emission lines of cadmium are located from the LIBS spectrum data. Under ideal conditions, the intensity of the emission lines increases with the increase of the element content. Therefore, the correlation between the line intensity and the cadmium content is evaluated by the linear correlation coefficient. The peak position corresponding to the target element can be found through the NIST database. Therefore, the wavelength position N of the characteristic peak with the strongest linear correlation with the cadmium content (i.e., the largest linear correlation coefficient) is selected from the NIST database. For example, the characteristic emission lines of cadmium (Cd) are at 214.44nm, 226.50nm, and 228.80nm. The line intensities of the n LIBS spectra obtained at the selected characteristic peak positions are [x N ]n. The linear correlation coefficient calculation formula is: r= .

[0072] where r is the linear correlation coefficient; is the serial number of the acquisition point; is the LIBS spectral intensity of the i-th acquisition point at the wavelength position N; is the mean value of the LIBS spectral intensities of the spectra of n acquisition points at the wavelength N; is the true value of the cadmium element content of the sample corresponding to the i-th acquisition point; is the mean value of the cadmium element content of Panax notoginseng where n acquisition points are located.

[0073] Calculate the set of intensity ratios to be detected for each ablation pit to be detected; the set of intensity ratios to be detected includes multiple intensity ratios to be detected. Among them, the j-th intensity ratio to be detected is the ratio of the intensity of the characteristic emission line to be detected and the intensity of the j-th non-characteristic emission line to be detected in the laser-induced breakdown spectrum to be detected corresponding to the ablation pit to be detected; 1 < j ≤ q - 1, and q is the total number of wavelengths of the laser-induced breakdown spectrum to be detected.

[0074] Based on the set of intensity ratios to be detected for each ablation pit to be detected and the intensity of the characteristic emission line to be detected, determine the corrected intensity of the characteristic emission line to be detected corresponding to the ablation pit to be detected.

[0075] As an optional implementation manner, the laser-induced breakdown spectrum to be detected is determined by using a laser-induced breakdown spectroscopy detection platform.

[0076] As an optional implementation manner, the shape parameter is determined by using a shape measurement laser microscopy system.

[0077] As an optional implementation manner, based on each sample laser-induced breakdown spectrum, determine the corrected intensity of the characteristic emission line of the corresponding sample ablation pit, specifically including:

[0078] Determine the characteristic emission line of the corresponding sample ablation pit from each sample laser-induced breakdown spectrum.

[0079] Calculate the set of sample intensity ratios for each sample ablation pit on each Panax notoginseng sample; the set of intensity ratios includes multiple sample intensity ratios. Among them, the j-th sample intensity ratio is the ratio of the intensity of the characteristic emission line and the intensity of the j-th non-characteristic emission line in the sample laser-induced breakdown spectrum corresponding to the corresponding sample ablation pit; 1 < j ≤ p - 1, p is the total number of wavelengths of the sample laser-induced breakdown spectrum, and p = q.

[0080] Based on the set of sample intensity ratios for each sample ablation pit and the intensity of the characteristic emission line of the sample, determine the corrected intensity of the characteristic emission line of the corresponding sample ablation pit.

[0081] Specifically, it is known that n groups of LIBS spectral matrices X = [x1,…,x p n*p ​And the corresponding true value of cadmium concentration of n groups of Panax notoginseng samples C n , p is the total number of wavelengths in the LIBS spectrum data, and p wavelengths constitute a LIBS spectrum line. From the LIBS spectrum matrix X, the jth wavelength position (j=1,2,…,p-1) is selected in sequence, and the corresponding signal intensity is recorded as z j , then z j ∈X, use the following formula to calculate the ratio of the characteristic peak intensity to the signal intensity (non-characteristic emission line) at each wavelength position in the LIBS spectrum:

[0082] B j =x N / z j .

[0083] Among them, B j is the ratio of the intensity of the characteristic emission line in the LIBS spectrum to the signal intensity at the jth wavelength position; N is the wavelength position corresponding to the element characteristic peak in the spectrum (i.e., the characteristic emission line); x N is the intensity of the characteristic emission line.

[0084] From n collection points, we get n groups B j The linear correlation coefficient between the characteristic peak correction intensity and the cadmium content was calculated using the following method: r j = .

[0085] Among them, B ji The corrected intensity is calculated by the ratio of the characteristic peak intensity at the i-th acquisition point to the signal intensity at the wavelength position j; y i is the true value of the cadmium content corresponding to the i-th collection point; is the mean of the spectral intensity; is the average value of cadmium content.

[0086] The spectrum band range consists of p wavelengths, so the calculated p correlation coefficients are sorted in descending order, and the first m (m≤30) correlation coefficients corresponding to [z j ] n The disturbance variable Z=[z1,…,z m ] n , use the following formula to calculate the mean of the filtered interference variables:

[0087] .

[0088] Thus, the corrected LIBS spectrum matrix X' is obtained: X'=[ ] n*p .

[0089] In the corrected LIBS spectrum matrix X', the signal intensity x corresponding to point N is N ' is the signal intensity after characteristic peak ratio correction. Specific embodiment:

[0091] Figure 2 Flowchart of the method for detecting the cadmium content of Panax notoginseng based on ablation pit shape compensation and characteristic peak ratio correction in a specific embodiment. Figure 2 As shown, the process of detecting the cadmium content of Panax notoginseng in a specific embodiment includes:

[0092] S1: Prepare Panax notoginseng sample. The specific preparation process is as follows:

[0093] Six different brands of Panax notoginseng powder were purchased commercially. A 0.01 mol / L Cd(NO₃)₂·4H₂O heavy metal solution was prepared. Different volumes of this solution were pipetted into 4 g of Panax notoginseng powder. After adding purified water and mixing thoroughly, the mixture was dried in an 80°C oven for 48 hours. This yielded samples spiked with Cd in a gradient distribution: 0, 0.5 μg / g, 1 μg / g, 10 μg / g, 20 μg / g, 30 μg / g, 40 μg / g, 50 μg / g, 60 μg / g, and 70 μg / g. The dried samples were ground and passed through a No. 4 sieve to obtain powder samples. A 0.2 g sample was weighed and pressed using a hydraulic press at 20 MPa for 30 seconds to produce discs with a diameter of 13 mm and a thickness of approximately 1 mm. A total of 60 Panax notoginseng pressed discs were prepared for analysis.

[0094] S2: Obtain spectral data, two-dimensional parameters of ablation crater shape, and true value of cadmium content.

[0095] S2.1: LIBS spectral data is acquired using a laser-induced breakdown spectroscopy detection system. The detection system is primarily composed of a laser, a spectrometer, a detector, a time delay generator, a motorized translation stage, and an optical path system. The laser provides the LIBS system with laser pulse energy; the constructed optical path system focuses the laser light 2 mm below the sample surface; the electromagnetic wave signal radiated by the plasma is split by the spectrometer, and the photodetector converts the optical signal into an electrical signal, which is then transmitted to a computer for reading and recording. This embodiment uses the CT monochromator SR500i, which has a wavelength range of 210 nm to 231 nm and a total of 1024 wavelength variables; a digital time delay generator is used for timing control between the laser and the ICCD detector; and the motorized translation stage controls the movement of the sample according to the set movement path, enabling the acquisition of LIBS signals at different locations on the sample. In this embodiment, the LIBS detection system parameters were set as follows: delay time 2 μs, integration time 8 μs, and laser energy 40 mJ. On the same sample, the laser ablated six points on the sample using a motorized translation stage, with each site being struck a cumulative total of nine times. The average value was used as the spectral data for a single site, resulting in six LIBS spectral data sets for one sample.

[0096] S2.2: Figure 3 This is a morphology of the ablation pit formed by laser ablation of the Panax notoginseng tablet according to the embodiment of the present invention. The two-dimensional parameters of the ablation pit formed at each hitting site of the laser ablation are obtained using a shape measurement laser microscope system, including: cross-sectional area A n , maximum depth D n , perimeter P n , vertical Feret diameter F n , surface area S n , used to characterize the shape characteristics of the ablation crater.

[0097] S2.3: Accurately weigh 0.1g of Panax notoginseng powder sample, add 5mL of concentrated nitric acid, place in a graphite digestion furnace at 110℃-120℃ for heating and digestion. After acid removal treatment, adjust the volume to 50mL, use a 5mL syringe to pass through a 0.22µm microporous filter membrane, filter 5mL into a centrifuge tube for loading onto the machine, and use inductively coupled plasma mass spectrometry to determine the cadmium content of Panax notoginseng as the true value. The results are shown in Table 1.

[0098] Table 1 Cadmium content of Panax notoginseng

[0099]

[0100] S3: Determine the characteristic emission lines of cadmium and the corresponding signal intensities.

[0101] According to the atomic spectrum database of the National Institute of Standards and Technology (NIST), the characteristic emission line of cadmium was located from the LIBS spectrum data. The cadmium atomic spectrum line 228.80 nm with the strongest linear correlation with the cadmium content was selected, that is, the wavelength position N was the 918th wavelength position, and the corresponding signal intensity was x N is x 918 .

[0102] S4: The interfering variables were determined by searching within the entire spectrum and the characteristic peak intensities were corrected using the ratio method.

[0103] Input 360 (60 samples × 6 collection points per sample) LIBS spectrum matrix X=[x1,…,x 1024 ] 360*1024 , sample element concentration matrix Y=[C] 360 . Let [z j ] 360 =[x j ] 360 , x j ∈X, and j = 1, 2, ..., 1024, calculate the ratio of the characteristic peak intensity and each spectral variable.

[0104] Then calculate the correlation between the ratio and the true value of cadmium content, sort the results of the correlation in descending order, and select the first 25 [z j ] n The disturbance variable Z=[z1,…,z 25 ] 360 , Figure 4 The position of the interference variable in the LIBS spectrum of the embodiment of the present invention (at the dot mark) is calculated, the mean value of the filtered interference variable is calculated, and the corrected LIBS spectrum matrix X' is determined. In X', the signal intensity x corresponding to 228.80nm is 918 ' is the signal intensity after characteristic peak ratio correction.

[0105] S5: The new response value is constructed by combining the characteristic peak intensity and the two-dimensional parameters of the ablation pit.

[0106] S5.1: Change x Nn 、A n 、D n 、P n 、F n 、S n As an independent variable, C n A multiple linear regression analysis is performed as the dependent variable to obtain the weighted regression coefficient β that reflects the importance of each independent variable. β is used as the coefficient of the corresponding independent variable to construct a new response value R.

[0107] S5.2: Let x Nn =[x 918 ] n , response value Let x N ' n =[x 918 '] n , response value .

[0108] S6: Establish a calibration curve model based on the new response value.

[0109] The calibration curve was drawn with the cadmium content of Panax notoginseng as the horizontal axis and the new response value as the vertical axis to obtain the linear fitting equation for predicting the cadmium content of Panax notoginseng. The model effect was expressed by the coefficient of determination (R 2 ) and root mean square error (RMSE) were used as evaluation indicators, and the results are shown in Table 2.

[0110] Table 2 Determination coefficient and root mean square error of different calibration curve models

[0111]

[0112] In this embodiment, it can be seen from the results in Table 2 that the calibration curve model of the cadmium content of Panax notoginseng established based on the new response value R2 has the best effect, shows a good correlation with the cadmium content of Panax notoginseng, and can effectively improve the accuracy and precision of the cadmium content prediction.

[0113] Beneficial effects:

[0114] (1) A ratio correction strategy is adopted to screen interference variables from the full spectrum to correct the characteristic peak signal intensity, effectively reducing the fluctuation of the target signal caused by interference, and improving the stability of the target element signal and the detection capability of the LIBS system.

[0115] (2) Based on multivariate linear regression analysis, the weighted regression coefficients were used as the weights of each independent variable when constructing a new response value, and the LIBS signal was compensated in multiple dimensions to more comprehensively characterize the association between Panax notoginseng samples and LIBS signals.

[0116] (3) The LIBS spectral signal and the corresponding two-dimensional parameters of the ablation pit shape are combined to construct a new response value, and the "shape" and "spectrum" features are integrated to establish a calibration curve regression model to improve the prediction effect of the model.

[0117] Example 2

[0118] Figure 5 This is a schematic diagram of the system structure for determining the cadmium content of Panax notoginseng provided in Example 2 of the present invention. Figure 5 As shown, the system for determining the cadmium content of Panax notoginseng in this embodiment includes:

[0119] The data acquisition module 201 is used to determine the laser induced breakdown spectrum and shape parameters of each ablation pit to be detected on the Panax notoginseng to be detected after laser ablation treatment; the shape parameters include: cross-sectional area, maximum depth, circumference, vertical Feret diameter and surface area.

[0120] The correction intensity determination module 202 is configured to determine the correction intensity of the characteristic emission line to be detected corresponding to the ablation pit to be detected based on each laser induced breakdown spectrum to be detected.

[0121] The cadmium content determination module 203 is used to determine the cadmium content of the Panax notoginseng to be tested based on the Panax notoginseng cadmium content fitting equation and all shape parameters and correction intensities of the Panax notoginseng to be tested; the Panax notoginseng cadmium content fitting equation is determined using the true values ​​of the cadmium content, shape parameters and correction intensities of the characteristic emission spectra of multiple Panax notoginseng samples.

[0122] Example 3

[0123] An electronic device, comprising:

[0124] One or more processors.

[0125] A storage device having one or more programs stored thereon.

[0126] When one or more programs are executed by one or more processors, the one or more processors implement the method for determining the cadmium content of Panax notoginseng as in Example 1.

[0127] Example 4

[0128] A storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for determining the cadmium content of Panax notoginseng as described in Example 1 is implemented.

[0129] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0130] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for determining the cadmium content of Panax notoginseng, characterized in that: The method includes: After laser ablation treatment on the Panax notoginseng to be detected, determining the laser-induced breakdown spectroscopy to be detected and shape parameters of each ablation pit to be detected on the Panax notoginseng to be detected; the shape parameters include: cross-sectional area, maximum depth, perimeter, vertical Feret diameter, and surface area; Based on each laser-induced breakdown spectroscopy to be detected, determining the corrected intensity of the characteristic emission spectral line corresponding to the ablation pit to be detected; Based on the Panax notoginseng cadmium content fitting equation and all the shape parameters and corrected intensities of the Panax notoginseng to be detected, determining the cadmium element content of the Panax notoginseng to be detected; the Panax notoginseng cadmium content fitting equation is determined by using the true values of the cadmium element content, shape parameters, and corrected intensities of the characteristic emission spectral lines of multiple Panax notoginseng samples; The determination process of the Panax notoginseng cadmium content fitting equation includes: Preparing multiple Panax notoginseng samples containing cadmium elements; Determining the true values of the cadmium element content of each Panax notoginseng sample; After laser ablation treatment on each Panax notoginseng sample, determining the sample laser-induced breakdown spectroscopy and shape parameters of each sample ablation pit on each Panax notoginseng sample; Based on each sample laser-induced breakdown spectroscopy, determining the corrected intensity of the sample characteristic emission spectral line corresponding to the sample ablation pit; Using the multiple linear regression method, based on the shape parameters and corrected intensities of the sample characteristic emission spectral lines of each sample ablation pit, determining the new response value corresponding to the sample ablation pit; The shape parameters of the ablation pits at n collection points of Panax notoginseng samples are recorded as: cross-sectional area A n , maximum depth D n , perimeter P n , vertical Feret diameter F n , surface area S n , which is used to describe the shape characteristics of the ablation crater; the signal intensity collected by the LIBS system is obtained by ratio correction to obtain x N ' n ; and the actual value of cadmium content C n , change x N ' n 、A n 、D n 、P n 、F n 、S n As an independent variable input, C n As the dependent variable output, through the multivariate linear regression method analysis, the weighted regression coefficient β reflecting the importance of each independent variable is obtained. β is used as the coefficient of the corresponding independent variable, and a new response value R is constructed as the vertical coordinate value. A calibration curve model based on the new response value is established as follows: R = β1x N ' n +β2A n +β3D n +β4P n +β5F n +β6S n , where β1, β2, β3, β4, β5, and β6 are the weighted regression coefficients corresponding to the input independent variables; Based on all the new response values and all the true values of the cadmium element content, determining the Panax notoginseng cadmium content fitting equation, taking the cadmium element content of the sample Panax notoginseng as the abscissa and the new response value as the ordinate, plotting a calibration curve, and obtaining a linear fitting equation for detecting the cadmium element content of Panax notoginseng; Based on each laser-induced breakdown spectroscopy to be detected, determining the corrected intensity of the characteristic emission spectral line corresponding to the ablation pit to be detected, specifically including: Determining the characteristic emission spectral line to be detected corresponding to the ablation pit to be detected from each laser-induced breakdown spectroscopy to be detected; Calculating the set of intensity ratios to be detected for each ablation pit to be detected; the set of intensity ratios to be detected includes multiple intensity ratios to be detected, where the jth intensity ratio to be detected is the ratio of the intensity of the characteristic emission spectral line to be detected and the intensity of the jth non-characteristic emission spectral line to be detected in the laser-induced breakdown spectroscopy to be detected corresponding to the ablation pit to be detected; 1 < j ≤ q - 1, and q is the total number of wavelengths of the laser-induced breakdown spectroscopy to be detected; Based on the set of intensity ratios to be detected and the intensity of the characteristic emission spectral line to be detected for each ablation pit to be detected, determining the corrected intensity of the characteristic emission spectral line corresponding to the ablation pit to be detected, specifically including: Given n sets of LIBS spectrum matrix X=[x1,…,x p ] n*p And the corresponding true value of cadmium concentration of n groups of Panax notoginseng samples C n , p is the total number of wavelengths of LIBS spectrum data, p wavelengths constitute a LIBS spectrum line, and the jth wavelength position (j = 1, 2, ..., p-1) is selected from the LIBS spectrum matrix X in sequence, and the corresponding signal intensity is recorded as z j , then z j ∈X, use the following formula to calculate the ratio of the characteristic peak intensity to the signal intensity at each wavelength position of the LIBS spectrum, that is, the non-characteristic emission line: j =x N / z j , where B j is the ratio of the intensity of the characteristic emission line in the LIBS spectrum to the signal intensity at the jth wavelength position; N is the wavelength position corresponding to the characteristic peak of the element in the spectrum, i.e., the characteristic emission line; x N is the intensity of the characteristic emission line; From n collection points, we get n groups B j With C, C is the actual cadmium content of Panax notoginseng sample, the linear correlation coefficient between the characteristic peak correction intensity and the cadmium content is calculated as follows: , where B ji The corrected intensity is calculated by the ratio of the characteristic peak intensity at the i-th acquisition point to the signal intensity at the wavelength position j; y i is the true value of the cadmium content corresponding to the i-th collection point; is the mean of the spectral intensity; is the mean value of cadmium content; The spectrum band range consists of p wavelengths. The p correlation coefficients are calculated and sorted in descending order. The first m correlation coefficients are selected. j ] n The disturbance variable Z=[z1,…,z m ] n , m≤30, use the following formula to calculate the mean of the filtered interference variables: , thus obtaining the corrected LIBS spectrum matrix X': , in the corrected LIBS spectrum matrix X', the signal intensity x corresponding to N N ' is the signal intensity after characteristic peak ratio correction.

2. The method for determining the cadmium content of Panax notoginseng according to claim 1, wherein: The laser-induced breakdown spectroscopy to be detected is determined by using a laser-induced breakdown spectroscopy detection platform.

3. The method for determining the cadmium content of Panax notoginseng according to claim 1, wherein: The shape parameters are determined by using a shape measurement laser microscopy system.

4. A system for determining the cadmium content of Panax notoginseng, the system being used to execute the method for determining the cadmium content of Panax notoginseng according to any one of claims 1 to 3, characterized in that: The system includes: A data acquisition module, configured to, after laser ablation treatment on the Panax notoginseng to be detected, determine the laser-induced breakdown spectroscopy to be detected and shape parameters of each ablation pit to be detected on the Panax notoginseng to be detected; the shape parameters include: cross-sectional area, maximum depth, perimeter, vertical Feret diameter, and surface area; a correction intensity determination module, configured to determine, based on each of the laser-induced breakdown spectra to be detected, a correction intensity of a characteristic emission line to be detected corresponding to the ablation pit to be detected; The cadmium content determination module is used to determine the cadmium content of the Panax notoginseng to be tested based on the Panax notoginseng cadmium content fitting equation and all shape parameters and correction intensities of the Panax notoginseng to be tested; the Panax notoginseng cadmium content fitting equation is determined using the true values ​​of the cadmium content, shape parameters and correction intensities of characteristic emission spectra of multiple Panax notoginseng samples.

5. An electronic device, characterized in that: include: one or more processors; a storage device having one or more programs stored thereon; When the one or more programs are executed by the one or more processors, the one or more processors implement the method for determining the cadmium content of Panax notoginseng as described in any one of claims 1 to 3.

6. A storage medium, characterized in that A computer program is stored thereon, wherein when the computer program is executed by a processor, the method for determining the cadmium content of Panax notoginseng as described in any one of claims 1 to 3 is implemented.

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