A method and system for detecting ultraviolet stabilizers in PET plastic bottles

Abstract

The present application relates to the technical field of ultraviolet stabilizer detection, and specifically to a method and system for detecting ultraviolet stabilizers in PET plastic bottles. The method comprises: obtaining chromatographic data of a sample to be tested in the PET plastic bottle, obtaining a basic baseline sequence, calculating the abnormal slope change degree of each element in the basic baseline sequence, extracting a response slope change sequence, and calculating the normal response correction value of each element therein; obtaining a baseline slope evaluation degree of the basic baseline sequence based on the average level of the normal response correction values ​​of each element in the response slope change sequence, combined with the average level of the filtered basic baseline sequence; and obtaining a true baseline sequence based on the comparison result of the baseline slope evaluation degree of the basic baseline sequence with a preset evaluation threshold, thereby detecting ultraviolet stabilizers in the PET plastic bottle. This application can improve the detection accuracy of ultraviolet stabilizers in plastic bottles.

Description

Technical Field

[0001] The present application relates to the technical field of ultraviolet stabilizer detection, and in particular to a method and system for detecting ultraviolet stabilizers in PET plastic bottles. Background Art

[0002] In order to increase the shelf life of pesticides, UV stabilizers can be added to PET plastic bottles. UV stabilizers can absorb or reflect ultraviolet rays, reduce the direct effect of ultraviolet rays on pesticide molecules, and delay the photochemical degradation process of pesticides, thereby improving the stability and utilization rate of pesticides. Therefore, the type and content detection of UV stabilizers is particularly important for the preservation of pesticides.

[0003] When measuring the type and content of UV stabilizers using high-performance liquid chromatography-mass spectrometry (HPLC-MS), the baseline of the HPLC data determines the accuracy of the results. Traditionally, the Savitzky-Golay (SG) filtering algorithm has been used to repeatedly fit the baseline of the HPLC data. However, due to the wide variety of pesticides that can be added to PET bottles, different compounds in these pesticides can have varying degrees of impact on the HPLC baseline offset. Therefore, using a fixed-number SG algorithm with iterative filtering is prone to underfitting, resulting in inaccurate fitting of the UV stabilizer baseline data and reduced accuracy in detecting the type and content of UV stabilizers. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a method and system for detecting ultraviolet stabilizers in PET plastic bottles. The technical solutions adopted are as follows:

[0005] The present invention provides a method for detecting ultraviolet stabilizers in PET plastic bottles, comprising the following steps:

[0006] Obtain chromatographic data of the sample to be tested in PET plastic bottles and arrange them in time sequence to form a stabilizer chromatographic sequence;

[0007] The stabilizer chromatographic sequence is segmented, and a basic baseline sequence is obtained based on the element values ​​in each segmented subsequence. The distribution differences of the chromatographic data in the basic baseline sequence before and after filtering are analyzed to obtain the abnormal slope change degree of each element in the basic baseline sequence.

[0008] By analyzing the distribution of abnormal slope variation, the peak widths corresponding to the peaks in all abnormal slope variation are clustered to obtain response peak clusters. According to the abnormal slope variation corresponding to the peaks in the response peak clusters, the response slope variation sequence is extracted and the normal response correction value of each element in it is calculated.

[0009] According to the average level of the normal response correction value of each element in the response slope change sequence and combined with the average level of the filtered basic baseline sequence, the baseline slope evaluation degree of the basic baseline sequence is obtained;

[0010] According to the comparison result of the baseline slope evaluation degree of the basic baseline sequence and the preset evaluation threshold, the real baseline sequence is obtained to detect the UV stabilizer in the PET plastic bottle.

[0011] Preferably, the method for obtaining the basic baseline sequence is:

[0012] The stabilizer chromatogram sequence is evenly divided into multiple stabilizer chromatogram subsequences. The first M smallest elements in each stabilizer chromatogram subsequence are selected to form each baseline estimation subsequence. The baseline estimation subsequence is interpolated and completed. The number of elements after completion is the length of the stabilizer chromatogram subsequence. All baseline estimation subsequences after interpolation and completion are merged according to the arrangement order of the corresponding stabilizer chromatogram subsequences. The merged sequence is used as the basic baseline sequence.

[0013] Preferably, the method for obtaining the abnormal slope variation of each element in the basic baseline sequence is:

[0014] Where, represents the abnormal slope change of the i-th element in the basic baseline sequence, represents the i-th element in the basic baseline slope sequence, represents the i-th element in the control baseline slope sequence;

[0015] Among them, the basic baseline sequence is filtered to obtain the control baseline sequence, the basic baseline sequence and the control baseline sequence are fitted respectively, and the slope of each data point is counted, and the slopes of all data points in the basic baseline sequence and the control baseline sequence are arranged according to the position order of the data points to obtain the basic baseline slope sequence and the control baseline slope sequence.

[0016] Preferably, the method for obtaining the response peak cluster is:

[0017] The abnormal slope change degrees of all elements are arranged according to the element position order in the basic baseline sequence to obtain the abnormal slope change sequence. The peak width corresponding to each peak in the abnormal slope change sequence is counted, and the peak widths corresponding to all peaks are clustered. The cluster with the largest mean is taken as the response peak cluster.

[0018] Preferably, the method for extracting the response slope change sequence is: arranging the abnormal slope change degrees corresponding to all peak widths in the response peak cluster according to their order in the abnormal slope change sequence to obtain the response slope change sequence.

[0019] Preferably, the method for obtaining the normal response correction value of each element in the response slope change sequence is:

[0020] Where, represents the normal response correction value of the jth element in the response slope change sequence, Represents the normalized value of the inverse of the jth element in the response slope change sequence, Represents the jth element in the response slope change sequence.

[0021] Preferably, the method for obtaining the baseline slope evaluation degree of the basic baseline sequence is:

[0022] Where, represents the baseline slope evaluation degree of the basic baseline sequence, represents the mean of the absolute values ​​of the elements in the control baseline slope series, Indicates a constant that avoids the denominator being 0, Represents the mean of the absolute values ​​of the elements in the baseline slope change sequence, where the normal response correction value of each element in the response slope change sequence replaces the element value at the corresponding position in the abnormal slope change sequence, and the replaced sequence is used as the baseline slope change sequence.

[0023] Preferably, the method for obtaining the true baseline sequence is:

[0024] When the baseline slope evaluation degree of the basic baseline sequence is less than the evaluation threshold, the basic baseline sequence is recorded as the true baseline sequence; otherwise, the control baseline sequence is used as a new stabilizer chromatographic sequence for repeated analysis to obtain a new basic baseline sequence and calculate its baseline slope evaluation degree until the baseline slope evaluation degree of the new basic baseline sequence is less than the evaluation threshold, and the new basic baseline sequence is recorded as the true baseline sequence.

[0025] Preferably, the method for detecting the UV stabilizer in the PET plastic bottle further comprises:

[0026] The difference sequence between the stabilizer chromatographic sequence and the true baseline sequence is calculated as the true chromatographic sequence of the stabilizer, and matched with the standard chromatographic data of the ultraviolet stabilizer to detect the ultraviolet stabilizer in PET plastic bottles.

[0027] An embodiment of the present application also provides a system for detecting ultraviolet stabilizers in PET plastic bottles, comprising a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any one of the above-mentioned methods for detecting ultraviolet stabilizers in PET plastic bottles are implemented.

[0028] As can be seen from the above, the method and system for detecting UV stabilizers in PET plastic bottles provided by this application have at least the following beneficial effects:

[0029] This application effectively addresses the detection error problem caused by baseline offset in traditional methods through sophisticated baseline correction. When detecting UV stabilizers in PET plastic bottles, the stabilizer chromatographic sequence can be accurately obtained, avoiding misjudgments caused by unstable baselines. This significantly improves the reliability of test results, ensuring that the test data more accurately reflects the actual sample conditions and providing a reliable basis for subsequent analysis and application.

[0030] Furthermore, this application can more accurately determine the response peak and peak width when calculating the UV stabilizer content. In the complex composition of PET plastic bottle liquids, the chromatographic peaks of different compounds overlap and interfere with each other, making it difficult to accurately distinguish and quantify them using traditional methods. However, this invention effectively isolates the UV stabilizer response peak through methods such as abnormal slope change analysis, accurately calculates its peak area, and thus achieves precise quantification.

[0031] In summary, this application can quickly and efficiently complete the comprehensive detection of UV stabilizers in PET plastic bottles through a systematic detection process. It can accurately detect a large number of samples in a short period of time and provide timely feedback on data, thereby improving detection efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 This is a flowchart of the steps of a method for detecting ultraviolet stabilizers in PET plastic bottles provided in this application. DETAILED DESCRIPTION

[0034] To further illustrate the technical means and effectiveness of this application's objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effectiveness of a method and system for detecting UV stabilizers in PET plastic bottles. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0035] Unless otherwise specified and limited, terms such as "comprises", "includes" or any other variants thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the article or device comprising the element. In addition, the term "and\or" used herein includes any and all combinations of one or more related listed items. All technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs.

[0036] The following describes in detail a method and system for detecting ultraviolet stabilizers in PET plastic bottles provided by the present application with reference to the accompanying drawings.

[0037] See also Figure 1 , which shows a flow chart of the steps of a method for detecting ultraviolet stabilizers in PET plastic bottles provided by one embodiment of the present application, comprising the following steps:

[0038] Step 1: Obtain the chromatographic data of the liquid in the PET plastic bottle and arrange them in time sequence to form a stabilizer chromatographic sequence.

[0039] In this embodiment, first, take 2g of liquid in a PET plastic bottle and put it into a 50mL stoppered glass reactor, add 20mL of organic solvent, the organic solvent can be toluene or tetrahydrofuran or acetone or dichloromethane or ethyl acetate. In this embodiment, the organic solvent toluene is selected, sealed and the sample to be tested is fully mixed, and then placed in an ultrasonic water bath. Ultrasonication is carried out at room temperature for 40 minutes, and an extract is obtained by an ultrasonic extractor. After the extract is cooled to room temperature, it is filtered through a 0.22μm PTFE membrane into a sample bottle, and then tested by an HPLC-MS detector. The test time is 70min, and the output is the response chromatographic data of the sample to be tested.

[0040] In this embodiment, the collection frequency of the collected response chromatographic data is 1 Hz, and the collection time is 70 minutes. The chromatographic data of the sample to be tested are arranged in the order of collection time to obtain the stabilizer chromatographic sequence.

[0041] Step 2: Segment the stabilizer chromatographic sequence and obtain a basic baseline sequence based on the element values ​​in each segmented subsequence. Analyze the distribution differences of the chromatographic data in the basic baseline sequence before and after filtering to obtain the abnormal slope change degree of each element in the basic baseline sequence.

[0042] During HPLC-MS measurements, the presence of multiple pesticide compounds in PET plastic bottles caused the chromatographic baseline of the UV stabilizer to shift. While the minimum value of the collected response chromatographic data can provide a rough estimate of the spectral baseline, the presence of multiple pesticide compounds during the test results can lead to peaks of other substances appearing in the data. Therefore, the minimum value cannot directly represent the approximate position of the spectral baseline.

[0043] Therefore, the stabilizer chromatogram sequence is evenly divided into N subsequences, denoted as stabilizer chromatogram subsequences. In this embodiment, N is 70. For each stabilizer chromatogram subsequence, the first M smallest elements in each stabilizer chromatogram subsequence are selected to form a baseline estimation subsequence. In this embodiment, M is 20.

[0044] Furthermore, linear interpolation is used to complete the baseline estimate subsequence. The number of elements after completion equals the length of the stabilizer chromatogram subsequence. For ease of understanding and presentation, this example denotes the completed sequence as the base baseline subsequence. All base baseline subsequences are merged according to the order of their corresponding stabilizer chromatogram subsequences, and the merged sequence is denotes the base baseline sequence. The baseline data distribution is obtained from the preliminary chromatographic data used to characterize the stabilizer chromatogram sequence. The linear interpolation calculation is well known, and the specific calculation steps are not detailed here.

[0045] Because SG filtering can correct outliers that deviate from the baseline back to the baseline, the base baseline sequence is used as the input for the SG filtering algorithm, and the output is a filtered base baseline sequence, which is recorded as the control baseline sequence. The calculation of the SG filter is well known, and the specific calculation steps are not repeated here.

[0046] Since the abnormal point is a sudden change signal relative to the baseline, the abnormal signal changes greatly after filtering. Therefore, the slope of the abnormal signal before and after filtering changes greatly, while the slope of the normal data changes less. Therefore, the basic baseline sequence and the control baseline sequence are used as inputs of the nonlinear least squares fitting algorithm respectively, and the corresponding fitting function can be obtained, and the slope of each data point is counted. Furthermore, the slopes of all data points in the basic baseline sequence and the control baseline sequence are arranged according to the position order of the data points to obtain the basic baseline slope sequence and the control baseline slope sequence, which are used to characterize the changes in the data state before and after filtering. The nonlinear least squares fitting algorithm is a well-known technology, and the specific calculation steps will not be repeated here.

[0047] Therefore, based on the degree of difference between the elements at the same position in the basic baseline slope sequence and the control baseline slope sequence, the abnormal slope change degree of each element in the basic baseline sequence is calculated. In this embodiment, the specific calculation formula is:

[0048] Where, represents the abnormal slope change of the i-th element in the basic baseline sequence, represents the i-th element in the basic baseline slope sequence, Represents the i-th element in the control baseline slope sequence.

[0049] The greater the difference between the base baseline slope sequence and the control baseline slope sequence at the same position, the more significant the change in the distribution of the values ​​of the element at that position before and after filtering, indicating that the element at that position is highly likely to be an anomaly. Baseline stability is crucial in the chromatographic analysis of UV stabilizers. The greater the difference in baseline data at a particular position before and after filtering, the less likely it is to be a normal, stable baseline for the UV stabilizer chromatographic data.

[0050] Step 3: By analyzing the distribution of abnormal slope changes, cluster the peak widths corresponding to the peaks in all abnormal slope changes to obtain response peak clusters. According to the abnormal slope changes corresponding to the peaks in the response peak clusters, extract the response slope change sequence and calculate the normal response correction value of each element therein.

[0051] Because the pesticide compounds in the PET bottles also cause response peaks in the chromatographic data, each substance will have a peak. Therefore, in addition to the UV stabilizer's response peak, response peaks for other non-UV stabilizer substances will also appear. Because SG filtering suppresses the multiple response peaks in the chromatographic data of the liquid in the PET bottle, the response peaks for non-UV stabilizer substances can also vary dramatically. However, the response peaks in the chromatographic data have a certain width, while the abnormal data has no peak width or a very small peak width.

[0052] Therefore, in this embodiment, all abnormal slope change degrees are arranged according to the order of corresponding elements in the base baseline sequence to obtain an abnormal slope change sequence. This abnormal slope change sequence is then used as input to a peak detection algorithm, with the output being a peak value. Furthermore, the peak width of each peak is calculated using an integration method to characterize the distribution of peak response values ​​in chromatographic data from PET bottles. The peak detection algorithm and the integration method for calculating peak widths are both well-known techniques, and the specific calculation steps are not further described here.

[0053] Because abnormal data can also cause a certain peak width, but its peak width is relatively short. Therefore, the peak widths of all peaks are used as input to the clustering algorithm. In this embodiment, the K-means clustering algorithm is used, and the output of the K-means algorithm is two clusters. The cluster with the largest mean among the clusters is recorded as the response peak cluster and used to characterize the width distribution of the response peak of the compound in the PET plastic bottle.

[0054] Furthermore, in this embodiment, the abnormal slope change degrees corresponding to the peak widths in the response peak clusters are extracted and arranged in order within the abnormal slope change sequence to obtain a response slope change sequence, which is used to characterize the post-filter baseline variation state of the chromatographic response of compounds in PET plastic bottles. The larger the element value in the response slope change sequence, the greater the influence of the element value on the baseline filter data. Therefore, the reciprocal of the elements in the response slope change sequence is normalized to characterize the normal suppression state of the filter slope variation. In this embodiment, an exponential normalization method is used. The specific normalization process is conventional and will not be further described in this embodiment.

[0055] Therefore, in this embodiment, the normal response correction value of each element in the response slope change sequence is calculated according to each abnormal slope change degree in the response slope change sequence. Preferably, the specific calculation formula is:

[0056] Where, represents the normal response correction value of the jth element in the response slope change sequence, Represents the normalized value of the inverse of the jth element in the response slope change sequence, Represents the jth element in the response slope change sequence.

[0057] Among them, the larger the peak width of the peak in the abnormal slope change sequence, the more likely that the element corresponding to the peak width is formed by the compound in the PET plastic bottle, and the larger the element value, the smaller the corresponding baseline data impact should be. Therefore, the smaller the normalized value of the reciprocal of the element value, the smaller the proportion of reducing the abnormal slope change, and the smaller the normal response correction value of the element. That is, this value can be used to effectively estimate the chromatographic baseline data of the liquid in the PET plastic bottle, and more accurately measure the type and content of the purple stabilizer in the PET plastic bottle.

[0058] Step 4: According to the average level of the normal response correction value of each element in the response slope change sequence and combined with the average level of the filtered basic baseline sequence, the baseline slope evaluation degree of the basic baseline sequence is obtained.

[0059] Furthermore, the normal response correction value of each element in the response slope change sequence is replaced with the element value of the element at the corresponding position in the abnormal slope change sequence. The replaced sequence is recorded as the baseline slope change sequence, which is used to characterize the change state of the baseline slope before and after filtering. The smaller the element transformation in the baseline slope change sequence, the smaller the difference between the elements before and after filtering, the lower the degree of change in the baseline response data before and after filtering, and the more likely the basic baseline sequence is to be the true baseline sequence of the liquid chromatography data in PET plastic bottles. Thus, the baseline slope evaluation degree of the current basic baseline sequence is calculated:

[0060] Where, represents the baseline slope evaluation degree of the basic baseline sequence, Represents the mean of the absolute values ​​of the elements in the baseline slope change sequence, represents the mean of the absolute values ​​of the elements in the control baseline slope series, Indicates a constant to prevent the denominator from being 0. The default value range is [0.1, 1]. In this embodiment, the value is 0.2.

[0061] The greater the ratio of the mean absolute values ​​of the elements in the baseline slope change sequence to the mean absolute values ​​of the elements in the control baseline slope sequence, the greater the difference in the slope change of the base baseline sequence before and after filtering, and the less likely this base baseline sequence is to be the true baseline sequence for the liquid chromatography data in PET bottles. Therefore, it is necessary to extract a new base baseline sequence to ensure that the extracted base baseline sequence is authentic and improve the detection results of UV stabilizers in PET bottles.

[0062] Step 5: Based on the comparison result of the baseline slope evaluation degree of the basic baseline sequence and the preset evaluation threshold, a true baseline sequence is obtained to detect the UV stabilizer in the PET plastic bottle.

[0063] Furthermore, in this embodiment, the baseline slope evaluation degree of the calculated base baseline sequence is compared with an evaluation threshold. In this embodiment, the evaluation threshold is set to 0.05. If the baseline slope evaluation degree of the base baseline sequence is less than the evaluation threshold, it indicates that the difference between the base baseline sequence before and after filtering is small. The base baseline sequence is the chromatographic data baseline for the PET plastic bottle, and the base baseline sequence is recorded as the true baseline sequence.

[0064] When the baseline slope evaluation degree of the basic baseline sequence is greater than or equal to the evaluation threshold, it indicates that the difference between the basic baseline sequence before and after filtering is significant, and it is necessary to continue to repeat the above steps and processes of this embodiment. Specifically, in this embodiment, the control baseline sequence is used as a new stabilizer chromatogram sequence, and the new stabilizer chromatogram sequence is segmented, minimal element extracted, interpolated, filtered, and other steps mentioned in this embodiment are performed to obtain a new basic baseline sequence and calculate the baseline slope evaluation degree. This process continues until the baseline slope evaluation degree of the new basic baseline sequence is less than the evaluation threshold, thereby obtaining a true baseline sequence.

[0065] Furthermore, a baseline correction was performed on the stabilizer chromatogram sequence collected from the PET plastic bottle using the true baseline sequence. This correction method calculated a difference sequence between the stabilizer chromatogram sequence and the true baseline sequence, and recorded this difference sequence as the true stabilizer chromatogram sequence. This difference sequence was then matched with standard chromatogram data for a UV stabilizer to determine the type of UV stabilizer. The UV stabilizer content was then determined based on the peak value and peak width of the response chromatogram. The measurement of standard chromatogram data for UV stabilizers and the calculation of the substance content based on the peak value and peak width are both well-known techniques, and the specific calculation steps are not detailed here.

[0066] Based on the same inventive concept as the above method, an embodiment of the present application also provides a system for detecting ultraviolet stabilizers in PET plastic bottles, comprising a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any one of the above-mentioned methods for detecting ultraviolet stabilizers in PET plastic bottles are implemented.

[0067] It should be understood that the order in which the embodiments of the present application are presented is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. Furthermore, the foregoing descriptions of specific embodiments of this specification are provided. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential sequence shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0068] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0069] The above content is only an implementation method of the present application and is not intended to limit the scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the scope of protection of the present application.

Claims

1. A method for detecting ultraviolet stabilizers in PET plastic bottles, characterized in that: The following steps are involved: Obtain chromatographic data of the sample to be tested in PET plastic bottles and arrange them in time sequence to form a stabilizer chromatographic sequence; The stabilizer chromatographic sequence is segmented, and the basic baseline sequence is obtained according to the element values ​​in each segmented subsequence. Calculate the abnormal slope change of each element in the basic baseline sequence. The expression is: Where, represents the abnormal slope change of the i-th element in the basic baseline sequence, represents the i-th element in the basic baseline slope sequence, represents the i-th element in the control baseline slope sequence; The basic baseline sequence is filtered to obtain a control baseline sequence, the basic baseline sequence and the control baseline sequence are fitted respectively, and the slope of each data point is counted. The slopes of all data points in the basic baseline sequence and the control baseline sequence are arranged according to the position order of the data points to obtain the basic baseline slope sequence and the control baseline slope sequence; The abnormal slope change degrees of all elements are arranged according to the order of the element positions in the basic baseline sequence to obtain an abnormal slope change sequence; by analyzing the distribution of the abnormal slope change degrees, the peak widths corresponding to the peaks in all abnormal slope change degrees are clustered to obtain response peak clusters; based on the abnormal slope change degrees corresponding to the peaks in the response peak clusters, the response slope change sequence is extracted and the normal response correction value of each element in it is calculated; Calculate the baseline slope evaluation of the basic baseline sequence. The expression is: Where, represents the baseline slope evaluation degree of the basic baseline sequence, represents the mean of the absolute values ​​of the elements in the control baseline slope series, Indicates a constant that avoids the denominator being 0, represents the mean of the absolute values ​​of the elements in the baseline slope change sequence, wherein the normal response correction value of each element in the response slope change sequence replaces the element value at the corresponding position in the abnormal slope change sequence, and the replaced sequence is used as the baseline slope change sequence; Based on the comparison results of the baseline slope evaluation degree of the basic baseline sequence and the preset evaluation threshold, the true baseline sequence is obtained to detect the UV stabilizer in PET plastic bottles; The method for obtaining the normal response correction value of each element in the response slope change sequence is: Where, represents the normal response correction value of the jth element in the response slope change sequence, Represents the normalized value of the inverse of the jth element in the response slope change sequence, Represents the jth element in the response slope change sequence.

2. The method for detecting ultraviolet stabilizers in PET plastic bottles according to claim 1, wherein: The method for obtaining the basic baseline sequence is: The stabilizer chromatogram sequence is evenly divided into multiple stabilizer chromatogram subsequences. The first M smallest elements in each stabilizer chromatogram subsequence are selected to form each baseline estimation subsequence. The baseline estimation subsequence is interpolated and completed. The number of elements after completion is the length of the stabilizer chromatogram subsequence. All baseline estimation subsequences after interpolation and completion are merged according to the arrangement order of the corresponding stabilizer chromatogram subsequences. The merged sequence is used as the basic baseline sequence.

3. The method for detecting ultraviolet stabilizers in PET plastic bottles according to claim 1, wherein: The method for obtaining the response peak cluster is: The peak width corresponding to each peak in the abnormal slope change sequence is counted, the peak widths corresponding to all peaks are clustered, and the cluster with the largest mean is taken as the response peak cluster.

4. The method for detecting ultraviolet stabilizers in PET plastic bottles according to claim 1, wherein: The method for extracting the response slope change sequence is as follows: arranging the abnormal slope change degrees corresponding to all peak widths in the response peak cluster according to their order in the abnormal slope change sequence to obtain the response slope change sequence.

5. The method for detecting ultraviolet stabilizers in PET plastic bottles according to claim 1, wherein: The method for obtaining the true baseline sequence is: When the baseline slope evaluation degree of the basic baseline sequence is less than the evaluation threshold, the basic baseline sequence is recorded as the true baseline sequence; Otherwise, the control baseline sequence is repeated as a new stabilizer chromatographic sequence to obtain a new basic baseline sequence and calculate its baseline slope evaluation degree until the baseline slope evaluation degree of the new basic baseline sequence is less than the evaluation threshold, and the new basic baseline sequence is taken as the true baseline sequence.

6. The method for detecting ultraviolet stabilizers in PET plastic bottles according to claim 1, wherein: The method for detecting the ultraviolet stabilizer in the PET plastic bottle further comprises: The difference sequence between the stabilizer chromatographic sequence and the true baseline sequence is calculated as the true chromatographic sequence of the stabilizer, and matched with the standard chromatographic data of the ultraviolet stabilizer to detect the ultraviolet stabilizer in PET plastic bottles.

7. A system for detecting ultraviolet stabilizers in PET plastic bottles, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method for detecting ultraviolet stabilizers in PET plastic bottles as described in any one of claims 1 to 6 are implemented.

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