Method for detecting content of bomeol in natural plant essential oil
Patent Information
- Application Number
- CN202611397653.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-09
- Publication Date
- 2026-10-27
AI Technical Summary
[0004]本发明提供天然植物精油中紫苏醇含量检测方法，以解决现有的问题
[0015]本发明的技术方案的有益效果是：本发明通过划分氧化测试节点对植物精油样本进行连续氧化测试，得到紫苏醇氧化测试含量以及氧化色谱图，可识别氧化标志物和干扰峰，为精油新鲜度评价与品质控制提供客观依据；对比紫苏醇氧化测试含量与紫苏醇原始测试含量的变化量，计算紫苏醇损失率，为区分天然组成差异与氧化损失提供关键依据；分析不同批次在同一氧化测试节点上氧化色谱图内峰值的对齐状态，从色谱峰值中筛选出候选峰，能够从复杂色谱信号中去除不稳定或与氧化无关的干扰峰，保留跨批次一致且对氧化敏感的特征峰；对比同一候选峰在色谱图内稳定性数值、平均数值以及紫苏醇损失率，计算批间离散系数与氧化敏感系数，能分别从跨批次一致性和氧化响应特性两个维度优选色谱峰，确保所选特征峰既受原料天然差异影响小；根据批间离散系数与氧化敏感系数，从候选峰中筛选出紫苏醇氧化特征峰，保留与氧化过程真实相关的稳定峰；综合分析紫苏醇氧化特征峰整体在色谱数值方面的稳定状态，计算精油新鲜度基准值，减少单一指标或批次差异带来的误判；基于每个批次下不同氧化测试节点的紫苏醇氧化测试含量与精油新鲜度基准值之间的偏差量，构建PLS损失模型，能够建立稳健的紫苏醇氧化损失预测关系，提高紫苏醇含量校正的准确性；本发明通过划分氧化测试节点进行连续氧化测试，获取紫苏醇氧化测试含量和色谱图，计算损失率并结合峰对齐筛选候选峰；利用批间离散系数和氧化敏感系数确定紫苏醇氧化特征峰，综合其特征计算精油新鲜度基准值，并据此构建PLS损失模型，正式计算待测样本的紫苏醇含量，更加准确地区分天然组成差异与储存氧化变化形成的差异，提高了紫苏醇含量检测的准确性。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of content detection technology, specifically to a method for detecting perillol content in natural plant essential oils. Background Technology
[0002] Natural plant essential oils are composed of various terpenes, terpene alcohols, aldehydes, and other volatile components. Their chemical composition is influenced by factors such as plant variety, raw material maturity, origin, and extraction process. Perillyl alcohol, as a characteristic terpene alcohol component in some natural plant essential oils, can be used to evaluate the composition and quality of the essential oil. Currently, perillyl alcohol content is typically detected using gas chromatography or gas chromatography-mass spectrometry. The essential oil sample is diluted and injected, and the corresponding chromatographic peak is determined based on a perillyl alcohol standard. The perillyl alcohol content at the detection time is then obtained from the peak area.
[0003] After production, natural plant essential oils are continuously affected by oxygen, temperature, and light during transportation, storage, and use, causing changes in perillaldehyde content due to oxidation and other losses. Perillaldehyde and other oxidation-related volatile components are naturally present in fresh essential oils, and their initial levels vary between different batches. Therefore, current techniques that rely solely on the current content of a single oxidation product or the current ratio of perillaldehyde to perillaldehyde to determine the degree of perillaldehyde loss can easily misinterpret differences in the natural composition of the raw material batches as changes caused by storage oxidation, failing to effectively determine the accurate perillaldehyde content in natural plant essential oils. Summary of the Invention
[0004] This invention provides a method for detecting perillol content in natural plant essential oils to solve existing problems.
[0005] The method for detecting perillyl alcohol content in natural plant essential oils of the present invention adopts the following technical solution: Includes the following steps: Obtain the original perillol content and chromatogram of each batch of plant essential oil samples, and obtain the original perillol content and chromatogram of the plant essential oil sample to be tested; the chromatogram contains multiple chromatographic peaks, and each chromatographic peak corresponds to a chromatographic value; Oxidation test nodes were defined, and continuous oxidation tests were conducted on plant essential oil samples from each batch to obtain the perillol oxidation test content and oxidation chromatogram at different oxidation test nodes for each batch. Compare the changes in perillaldehyde content during oxidation testing with the original perillaldehyde content, and calculate the perillaldehyde loss rate at each oxidation testing node; analyze the alignment of peak values in the oxidation chromatograms of different batches at the same oxidation testing node, and select several candidate peaks for each batch from the chromatographic peaks; Within the overall batch, compare the change between the stability value and the average value of the same candidate peak in the chromatogram to calculate the inter-batch dispersion coefficient of the same candidate peak; compare the change between the numerical trend of the loss rate of perillaldehyde of the same candidate peak and the stability value in the chromatogram to calculate the oxidation sensitivity coefficient of the same candidate peak; based on the inter-batch dispersion coefficient and the oxidation sensitivity coefficient, select several perillaldehyde oxidation characteristic peaks from the candidate peaks. The stability of the overall chromatographic values of the perillol oxidation characteristic peaks was comprehensively analyzed, and the baseline value of the overall essential oil freshness of the plant essential oil samples was calculated. Based on the deviation between the perillol oxidation test content at different oxidation test nodes in each batch and the baseline value of essential oil freshness, a PLS loss model was constructed, and the perillol content of the plant essential oil samples to be tested was detected to obtain the true perillol content of the plant essential oil samples to be tested.
[0006] Preferably, the method for obtaining the perillaldehyde oxidation test content and the oxidation chromatogram is as follows: Plant essential oil samples from the same batch were divided into several continuous oxidation test samples. Several time monitoring points were preset for each continuous oxidation test sample as oxidation test nodes. The original perillol content at each oxidation test node was recorded and used as the perillol oxidation test content at each oxidation test node. Chromatographic detection was performed on the continuous oxidation test samples under each oxidation test node to obtain the chromatogram of each oxidation test node, which was used as the oxidation chromatogram.
[0007] Preferably, the method for obtaining the perillaldehyde loss rate is as follows: At the same oxidation test node, the standardized difference between the perillol oxidation test content and the original perillol test content is taken as the perillol loss rate at the same oxidation test node.
[0008] Preferably, the method for obtaining the candidate peak is as follows: The coordinate space of the oxidation chromatograms of different batches at the same oxidation test node is superimposed, and the chromatographic peaks with the vertical axis values that are less than the preset vertical axis difference threshold are used as candidate peaks for different batches.
[0009] Preferably, the method for obtaining the batch-to-batch dispersion coefficient is as follows: The standard deviation of the chromatographic values of the same candidate peak in all chromatograms is used as the initial sample standard deviation of the same candidate peak; the mean of the chromatographic values of the same candidate peak in all chromatograms is used as the initial mean of the chromatographic response of the same candidate peak; and the ratio mapping result of the initial sample standard deviation and the initial mean of the chromatographic response is used as the inter-batch dispersion coefficient of the same candidate peak.
[0010] Preferably, the method for obtaining the oxidation sensitivity coefficient is as follows: Using the perillaldehyde loss rate as the oxidation horizontal axis and the difference in chromatographic values between the chromatogram and the oxidation chromatogram of the same candidate peak as the oxidation vertical axis, a two-dimensional space for the oxidation characteristics of perillaldehyde was constructed using the oxidation horizontal and vertical axes. All candidate peaks were input into the two-dimensional space for oxidation characteristics to generate several oxidation coordinate points. All oxidation coordinate points were fitted to calculate the trend slope of the perillaldehyde loss rate of the same candidate peak. The ratio mapping result of the perillaldehyde loss rate trend slope to the initial sample standard deviation was used as the oxidation sensitivity coefficient of the same candidate peak.
[0011] Preferably, the method for obtaining the characteristic peak of perillaldehyde oxidation is as follows: By setting a preset threshold for the inter-batch dispersion coefficient, several candidate peaks of natural differential essential oils were selected. By setting a preset threshold for the oxidation sensitivity coefficient, several characteristic peaks of perillyl alcohol oxidation were selected.
[0012] Preferably, the method for obtaining the oil freshness benchmark value is as follows: The standard deviation of the chromatographic values of all perillaldehyde oxidation characteristic peaks was used as the benchmark value for the overall freshness of the plant essential oil samples.
[0013] Preferably, the method for obtaining the PLS loss model is as follows: The deviation between the perillaldehyde oxidation test content and the essential oil freshness benchmark value at different oxidation test nodes in each batch was analyzed, and the structural feature deviation of each oxidation test node in each batch was calculated. The structural feature deviation of each oxidation test node in each batch was used as the independent variable of the PLS loss model, and regression training was performed to calculate several essential oil regression coefficients of the PLS loss model. The PLS loss model reconstructed from the essential oil regression coefficients was used as the PLS loss model for plant essential oil samples.
[0014] Preferably, the method for obtaining the construction feature deviation is as follows: The standardized difference between the perillol oxidation test content at each oxidation test node in each batch and the essential oil freshness benchmark value is used as the structural characteristic deviation at each oxidation test node in each batch.
[0015] The beneficial effects of the technical solution of this invention are as follows: This invention performs continuous oxidation testing on plant essential oil samples by dividing oxidation test nodes, obtaining perillaldehyde oxidation test content and oxidation chromatograms, which can identify oxidation markers and interference peaks, providing an objective basis for essential oil freshness evaluation and quality control; by comparing the change in perillaldehyde oxidation test content with the original perillaldehyde test content, the perillaldehyde loss rate is calculated, providing a key basis for distinguishing between differences in natural composition and oxidation loss; by analyzing the alignment status of peaks in the oxidation chromatograms of different batches at the same oxidation test node, candidate peaks are screened from the chromatographic peaks, which can remove unstable or oxidation-irrelevant interference peaks from complex chromatographic signals, retaining characteristic peaks that are consistent across batches and sensitive to oxidation; by comparing the stability value, average value, and perillaldehyde loss rate of the same candidate peak in the chromatogram, the inter-batch dispersion coefficient and oxidation sensitivity coefficient are calculated, which can optimize the chromatographic peaks from two dimensions: inter-batch consistency and oxidation response characteristics, ensuring that the selected characteristic peaks are less affected by the natural differences in raw materials; based on the inter-batch dispersion coefficient and oxidation sensitivity coefficient, the chromatographic peaks can be optimized ... chromatographic peaks are optimized from two dimensions: inter-batch consistency and oxidation response characteristics, ensuring Sensitivity coefficients are used to screen perillaldehyde oxidation characteristic peaks from candidate peaks, retaining stable peaks that are truly related to the oxidation process. A comprehensive analysis of the overall stability of the perillaldehyde oxidation characteristic peaks in terms of chromatographic values is conducted to calculate the essential oil freshness benchmark, reducing misjudgments caused by single indicators or batch differences. Based on the deviation between the perillaldehyde oxidation test content and the essential oil freshness benchmark at different oxidation test nodes in each batch, a PLS loss model is constructed, which can establish a robust perillaldehyde oxidation loss prediction relationship and improve the accuracy of perillaldehyde content correction. This invention performs continuous oxidation tests by dividing oxidation test nodes, obtaining perillaldehyde oxidation test content and chromatograms, calculating the loss rate, and screening candidate peaks by combining peak alignment. The perillaldehyde oxidation characteristic peaks are determined using inter-batch dispersion coefficients and oxidation sensitivity coefficients, and the essential oil freshness benchmark is calculated based on these characteristics. A PLS loss model is then constructed to formally calculate the perillaldehyde content of the sample to be tested, more accurately distinguishing between differences in natural composition and differences caused by storage oxidation changes, thus improving the accuracy of perillaldehyde content detection. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a flowchart of the steps in the method for detecting perillol content in natural plant essential oils according to the present invention; Figure 2 This is a schematic diagram showing the time series changes of the main components during the perilla alcohol oxidation process of the present invention; Figure 3 This is a schematic diagram comparing the chromatograms and oxidation chromatograms of the present invention; Figure 4 This is a schematic diagram illustrating the screening process of candidate peaks based on batch-to-batch dispersion coefficient and oxidation sensitivity coefficient in this invention. Figure 5 This is a schematic diagram of the batch cross-validation results of the PLS loss model of the present invention; Figure 6 This is a schematic diagram of the predicted residual distribution of the PLS loss model of the present invention. Detailed Implementation
[0018] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the method for detecting perillol content in natural plant essential oils proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.
[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0020] The following describes in detail the specific scheme of the method for detecting perillol content in natural plant essential oils provided by the present invention, with reference to the accompanying drawings.
[0021] Please see Figure 1 The diagram illustrates a flowchart of a method for detecting perillaldehyde content in natural plant essential oils according to an embodiment of the present invention. The method includes the following steps: Step S001: Obtain the original perillol content and chromatogram of each batch of plant essential oil samples, and obtain the original perillol content and chromatogram of the plant essential oil sample to be tested; the chromatogram contains multiple chromatographic peaks, and each chromatographic peak corresponds to a chromatographic value.
[0022] It should be noted that after the production of natural plant essential oils, they are continuously affected by oxygen, temperature, and light during transportation, storage, and use, causing changes in perillaldehyde content due to oxidation and other losses. Perillaldehyde and other oxidation-related volatile components are naturally present in fresh essential oils, and their initial levels vary between different batches of raw materials. Therefore, current techniques that rely solely on the current content of a single oxidation product or the current ratio of perillaldehyde to perillaldehyde to determine the degree of perillaldehyde loss can easily misinterpret the natural compositional differences between batches of raw materials as changes caused by storage oxidation, failing to effectively determine the accurate perillaldehyde content in natural plant essential oils.
[0023] In one specific implementation of this invention, the process of obtaining the original perillaldehyde content and chromatogram is as follows: Extract essential oils of the same type as the plant essential oil to be tested from the plant essential oil sample bank. Freshly produced natural plant essential oils were collected and used as plant essential oil samples. Chromatographic content detection technology was used to analyze the plant essential oils and each batch of plant essential oil samples to obtain the original perillaldehyde content and chromatograms for each batch of plant essential oil samples. Each chromatogram contains multiple chromatographic peaks, and each chromatographic peak corresponds to a chromatographic value.
[0024] It should be noted that, in this embodiment, the following is used: This example is used for illustration; no specific limitations are set in this embodiment. This can be determined based on the specific implementation. The multiple batches of plant essential oil samples selected in this embodiment are all of the same type. The content of each batch of plant essential oil samples is described in this embodiment using 50ml as an example; the specific value can be determined based on the implementation.
[0025] It should be noted that the chromatographic content detection technology used in this embodiment is an existing technique. The general process of this existing technique is as follows: A quantitative amount of essential oil sample is taken and diluted to volume using a gas chromatographic grade organic solvent that has been confirmed by a blank test not to co-elute with perillaldehyde and the main candidate peaks. A fixed concentration of internal standard is added. The internal standard is also confirmed by a blank test to separate from the target peak and candidate peaks, and remains unchanged after model development. If the sample contains plant residues, waxes, or other non-volatile particles, it is filtered after dilution. All fresh samples, oxidized samples, and subsequent actual test samples maintain consistent sampling volume, dilution factor, internal standard concentration, and gas chromatography-mass spectrometry (GC-MS) analysis conditions. GC-MS determines the retention time and characteristic ions of perillaldehyde using perillaldehyde standards, and establishes a quantitative curve using a series of standards at no less than 5 concentration points. The coefficient of determination of the quantitative curve is no less than 0.995, thereby obtaining the initial measured content of perillaldehyde for each fresh batch. Simultaneously, complete GC-MS chromatograms for each batch are saved, including the retention time, peak area, and corresponding mass spectrometry information of each common peak. The set values included in the above chromatographic content detection techniques are all empirical reference values, and the specific values can be determined according to the implementation situation, which will not be elaborated in this embodiment.
[0026] Thus, the original perillaldehyde content and chromatogram were obtained using the above method.
[0027] Step S002: Divide the oxidation test nodes and conduct continuous oxidation tests on the plant essential oil samples of each batch to obtain the perillol oxidation test content and oxidation chromatogram of each batch at different oxidation test nodes.
[0028] It should be noted that, in order to dynamically characterize the oxidation process and improve the accuracy of perillol detection and correction, oxidation nodes were defined and continuous oxidation tests were conducted. Determining multiple oxidation nodes can effectively reflect the nonlinear loss patterns of perillol and other perillol oxidation products, obtaining loss curves and rate parameters, facilitating the backtesting of initial contents. Continuous monitoring can also verify the peak area stability of candidate internal standards during oxidation, ensuring effective normalization correction. Furthermore, by observing the process of the perillaldehyde / perillol ratio fluctuating naturally and then steadily increasing, an oxidation discrimination threshold can be scientifically set, reducing false positives and false negatives. Chromatograms at each node can identify target peak interference and new oxidation markers, improving specificity. After establishing a batch oxidation behavior database, actual detection can more accurately backtest the initial value and evaluate the degree of oxidation based solely on the current content, thereby effectively distinguishing between differences in natural composition and changes in storage oxidation. Please refer to [link to relevant documentation]. Figure 2 It shows a schematic diagram of the time series changes of the main components during the oxidation of perilla alcohol.
[0029] Preferably, in some implementations of the present invention, the method for obtaining the perillaldehyde oxidation test content and oxidation chromatogram is as follows: The same batch of plant essential oil samples is evenly divided into several continuous oxidation test samples; several time monitoring points are preset for each continuous oxidation test sample as oxidation test nodes; the original perillaldehyde test content at each oxidation test node is recorded and used as the perillaldehyde oxidation test content at each oxidation test node; chromatographic detection is performed on the continuous oxidation test samples under each oxidation test node to obtain the chromatogram of each oxidation test node, which is then used as the oxidation chromatogram. An example process is as follows: Each batch of plant essential oil samples was divided into equal parts. A continuous oxidation test sample, preset The process involved identifying several time points, each designated as an oxidation test node. Each consecutive oxidation test sample was placed in a sealed space at a predetermined oxidation temperature. Chromatographic content detection technology was used to obtain the original perillaldehyde content and chromatogram for each oxidation test node in chronological order. The original perillaldehyde content at each oxidation test node was taken as the perillaldehyde oxidation test content, and the chromatogram of each oxidation test node was taken as the oxidation chromatogram.
[0030] Furthermore, the perillaldehyde oxidation test content and oxidation chromatogram were obtained for different oxidation test nodes in each batch.
[0031] It should be noted that, in this embodiment, the following is used: , This example is used for illustration; no specific limitations are set in this embodiment. , This can be adjusted according to specific implementation conditions. This embodiment uses three preset oxidation temperatures of 25℃, 40℃, and 60℃ as examples, where the oxidation temperature is consistent with the number of samples in the continuous oxidation test. Furthermore, this embodiment uses five oxidation test points—day 1, day 3, day 7, day 14, and day 28—as examples, which will not be elaborated upon further in this embodiment.
[0032] Thus, the perillaldehyde oxidation test content and oxidation chromatogram for each batch at different oxidation test nodes were obtained using the above method.
[0033] Step S003: Compare the change in perillaldehyde oxidation test content with the original perillaldehyde test content, calculate the perillaldehyde loss rate at each oxidation test node; analyze the alignment status of peaks in the oxidation chromatogram of different batches at the same oxidation test node, and screen out several candidate peaks for each batch from the chromatographic peaks.
[0034] It should be noted that, in order to quantify the degree of oxidation and support subsequent correction and discrimination, we considered comparing the perillol oxidation test content with the original test content and calculating the perillol loss rate at each oxidation test node. The perillol loss rate directly reflects the actual reduction of perillol during storage or accelerated oxidation and is a fundamental parameter of oxidation kinetics. By using the perillol loss rate at each oxidation test node, we can fit a perillol loss curve over time, obtain the rate constant and half-life, and provide a basis for extrapolating the initial content from the current content at any time point. Simultaneously, combining the perillol loss rate with the increment of perillaldehyde allows for the measurement of stoichiometric coefficients, avoiding biases caused by fixed assumptions. The change process of the perillol loss rate also helps to determine the critical node of significant oxidation, scientifically set the discrimination threshold, and distinguish between natural composition fluctuations and true oxidation loss. Please refer to [link to relevant documentation]. Figure 3 It shows a schematic diagram comparing chromatograms and oxidation chromatograms.
[0035] Preferably, in some implementations of the present invention, the method for obtaining the perillaldehyde loss rate is as follows: at the same oxidation test node, the standardized difference between the perillaldehyde oxidation test content and the original perillaldehyde test content is used as the perillaldehyde loss rate at the same oxidation test node. An example process is as follows: At the same oxidation test node, the absolute value of the difference between the perillol oxidation test content and the original perillol test content is taken as the perillol loss difference value at the same oxidation test node. The perillol loss difference values for all oxidation test nodes are normalized, and each normalized perillol loss difference value is taken as the perillol loss rate. Each oxidation test node corresponds to one perillol loss rate.
[0036] It should be noted that this embodiment defaults to... Normalization is performed on the function as an example, and the implementer can choose the normalization function according to the actual situation.
[0037] It should be noted that analyzing the alignment of peaks in oxidation chromatograms from different batches at the same oxidation test node, and selecting several candidate peaks from each batch, aims to establish a comparable chromatographic information foundation across batches in the complex and variable composition of natural essential oils. This provides a reliable basis for subsequent selection of stable internal standards, identification of oxidation markers, and construction of calibration models. Because different batches of essential oils have inherent differences in their natural composition, and chromatographic retention times may drift due to instrument, matrix, or sample conditions, directly comparing peak areas or peak heights can easily lead to mismatches. By aligning chromatographic peaks at the same time point, corresponding compound peaks from different batches can be accurately matched, distinguishing common components from batch-specific components, thus avoiding misidentifying peaks with similar retention times but different chemical natures as the same substance. Based on this, candidate peak selection can identify peaks with clear behavioral characteristics during oxidation from a large number of chromatographic signals: one type is potential stable internal standards whose peak areas remain basically unchanged during continuous oxidation, used for normalization correction to eliminate differences in injection and matrix; the other type is potential oxidation markers that change regularly with the degree of oxidation, used to assist in determining the oxidation stage and verifying perillol loss. Alignment can also reveal peak splitting, overlapping, or drift, helping to eliminate interfering peaks and improve the accuracy of target analyte quantification.
[0038] Preferably, in some implementations of the present invention, the method for obtaining candidate peaks is as follows: the oxidation chromatograms of different batches at the same oxidation test node are overlapped in coordinate space, and the chromatographic peaks with a vertical axis value difference less than a preset vertical axis difference threshold are used as candidate peaks for different batches. An example process is as follows: Following the batch acquisition order, oxidation chromatograms from all batches at the same oxidation test node are sequentially placed in the same two-dimensional coordinate space. A preset vertical axis difference threshold is established. Taking any two adjacent chromatographic peaks on the horizontal axis in this two-dimensional coordinate space as an example, if the absolute value of the difference between these two chromatographic peaks on the vertical axis is less than... Therefore, both of these chromatographic peaks are considered as candidate peaks, and this process is repeated to obtain all candidate peaks for each batch. In this embodiment, [the following is an example / example] is used. This example is used for illustration; no specific limitations are set in this embodiment. It depends on the specific implementation situation.
[0039] Thus, several candidate peaks for each batch are obtained using the above method.
[0040] Step S004: Under the overall batch, compare the change between the stability value and the average value of the same candidate peak in the chromatogram to calculate the inter-batch dispersion coefficient of the same candidate peak; compare the change between the numerical trend of the perillaldehyde loss rate of the same candidate peak and the stability value in the chromatogram to calculate the oxidation sensitivity coefficient of the same candidate peak; based on the inter-batch dispersion coefficient and the oxidation sensitivity coefficient, select several perillaldehyde oxidation characteristic peaks from the candidate peaks.
[0041] It should be noted that calculating the inter-batch dispersion coefficient aims to screen for stable internal standards or characteristic peaks across batches, ensuring the universality of the calibration method. Because the natural compositional differences between different batches of essential oils cause fluctuations in the candidate peak response, intra-batch stability does not guarantee inter-batch stability. Using peaks with large inter-batch fluctuations as internal standards will introduce additional errors. A small inter-batch dispersion coefficient indicates that the peak is less affected by raw material differences and is suitable as a stable internal standard to eliminate injection, matrix, and instrument errors; a large inter-batch dispersion coefficient is unsuitable as a unified internal standard but can be used as a characteristic peak. Therefore, this step is crucial for candidate peak selection, avoiding confusion between differences in natural composition and changes in storage oxidation.
[0042] Preferably, in some implementations of the present invention, the method for obtaining the inter-batch dispersion coefficient is as follows: the standard deviation of the chromatographic values of the same candidate peak in all chromatograms is used as the initial sample standard deviation of the same candidate peak; the mean of the chromatographic values of the same candidate peak in all chromatograms is used as the initial mean of the chromatographic response of the same candidate peak; and the ratio mapping result between the initial sample standard deviation and the initial mean of the chromatographic response is used as the inter-batch dispersion coefficient of the same candidate peak. An example process is as follows: The standard deviation of the chromatographic values of the time interval corresponding to the same candidate peak in all chromatograms is used as the initial sample standard deviation of the same candidate peak; the mean of the chromatographic values of the time interval corresponding to the same candidate peak in all chromatograms is used as the initial mean of the chromatographic response of the same candidate peak; and the ratio of the initial sample standard deviation to the initial mean of the chromatographic response is used as the inter-batch dispersion coefficient of the same candidate peak.
[0043] It is important to note that calculating the oxidation sensitivity coefficient aims to screen out peaks that truly remain unchanged during oxidation as internal standards, while simultaneously identifying oxidation-sensitive peaks as auxiliary markers. Simply observing intra- or inter-batch variation is insufficient to determine whether candidate peaks change with oxidation. If oxidation-sensitive peaks are mistakenly used as internal standards, it will mask the true loss of perillaldehyde, rendering the calibration ineffective. A small oxidation sensitivity coefficient indicates that the peak does not change with perillaldehyde oxidation and is suitable for normalization calibration; a large oxidation sensitivity coefficient indicates that the peak is related to the oxidation process and can be used to indicate the degree of oxidation or participate in the calibration model. Therefore, this step is a further optimization of candidate peaks, ensuring the internal standard is truly stable and distinguishing between differences in natural composition and changes caused by oxidation.
[0044] Preferably, in some implementations of the present invention, the method for obtaining the oxidation sensitivity coefficient is as follows: The perillaldehyde loss rate is used as the oxidation horizontal axis, and the difference in chromatographic values between the chromatogram and the oxidation chromatogram of the same candidate peak is used as the oxidation vertical axis. A two-dimensional space for the oxidation characteristics of perillaldehyde is constructed using the oxidation horizontal and vertical axes. All candidate peaks are input into this two-dimensional space to generate several oxidation coordinate points. All oxidation coordinate points are fitted to calculate the slope of the perillaldehyde loss rate trend for the same candidate peak. The ratio of the perillaldehyde loss rate trend slope to the initial sample standard deviation is used as the oxidation sensitivity coefficient for the same candidate peak. An example process is as follows: The mean value of the chromatographic values of the time interval corresponding to the same candidate peak in the oxidation chromatogram is taken as the mean value of the oxidation chromatographic response of the same candidate peak; the loss rate of perillyl alcohol is taken as the oxidation horizontal axis, and the absolute value of the difference between the mean value of the initial chromatographic response and the mean value of the oxidation chromatographic response of the same candidate peak is taken as the oxidation vertical axis; a two-dimensional space of the oxidation characteristics of perillyl alcohol is constructed through the oxidation horizontal axis and the oxidation vertical axis, and all candidate peaks are input into the two-dimensional space of the oxidation characteristics to generate several oxidation coordinate points.
[0045] Furthermore, a univariate linear fit was performed on all oxidation coordinate points of the same candidate peak, and the slope of the fitted line was calculated and used as the trend slope of the perillol loss rate of the same candidate peak. The ratio of the trend slope of the perillol loss rate to the initial sample standard deviation was used as the oxidation sensitivity coefficient of the same candidate peak.
[0046] It should be noted that the process of fitting the line based on two-dimensional coordinate points to obtain the slope of the fitted line is a well-known aspect of univariate linear fitting algorithms, and will not be elaborated upon in this embodiment.
[0047] It should be noted that a large inter-batch dispersion coefficient indicates that the peak itself fluctuates significantly across different batches. Even if it changes with oxidation, it is difficult to distinguish whether the variation is due to differences in raw materials or oxidation itself. Therefore, candidate peaks that are stable across batches should be retained first. Based on this, the oxidation sensitivity coefficient should be determined to reliably judge the trend of the peak as the perillol loss rate changes: peaks with larger coefficients can be selected as oxidation markers, while those with smaller coefficients can be used as internal standards. If the order is reversed, peaks with large inter-batch fluctuations but seemingly sensitive within a single batch may be selected, which are actually unusable for general calibration. Please refer to [link to relevant documentation]. Figure 4 It shows a schematic diagram of the candidate peak screening process based on the batch-to-batch dispersion coefficient and oxidation sensitivity coefficient.
[0048] Preferably, in some implementations of the present invention, the method for obtaining the perillaldehyde oxidation characteristic peak is as follows: the inter-batch dispersion coefficients of candidate peaks are screened using a preset threshold for the inter-batch dispersion coefficient to select several naturally differentiated essential oil candidate peaks; the oxidation sensitivity coefficients of the naturally differentiated essential oil candidate peaks are screened using a preset threshold for the oxidation sensitivity coefficient to select several perillaldehyde oxidation characteristic peaks. An example process is as follows: Batch-to-batch dispersion coefficient greater than a preset threshold Candidate peaks were selected as candidate peaks for naturally differentiated essential oils; peaks with oxidation sensitivity coefficients greater than a preset threshold were considered. The natural differential essential oil candidate peaks are used as characteristic peaks of perillyl alcohol oxidation.
[0049] It should be noted that, in this embodiment, the following is used: , This example is used for illustration; no specific limitations are set in this embodiment. , It depends on the specific implementation situation.
[0050] Thus, several characteristic peaks of perillaldehyde oxidation were obtained using the above method.
[0051] Step S005: Analyze the overall stability of the perillol oxidation characteristic peaks in terms of chromatographic values, and calculate the overall essential oil freshness benchmark value of the plant essential oil samples; based on the deviation between the perillol oxidation test content at different oxidation test nodes in each batch and the essential oil freshness benchmark value, construct a PLS loss model, and detect the perillol content of the plant essential oil samples to be tested to obtain the true perillol content of the plant essential oil samples to be tested.
[0052] It should be noted that the calculation of the essential oil freshness benchmark aims to construct a comprehensive quantitative index reflecting the degree of oxidation and freshness of essential oils. Since a single characteristic peak is easily affected by batch-to-batch variations in raw materials, instrument fluctuations, or localized oxidation changes, multiple perillaldehyde oxidation characteristic peaks, screened by inter-batch dispersion coefficients and oxidation sensitivity coefficients, can collectively characterize the oxidation state of essential oils from different perspectives. The distribution of these characteristic peak chromatographic values (such as peak area ratio and normalized intensity) in fresh samples is statistically integrated, and the resulting freshness benchmark represents the overall chromatographic baseline when no significant oxidation has occurred.
[0053] Preferably, in some implementations of the present invention, the method for obtaining the oil freshness benchmark value is as follows: the standard deviation of the chromatographic values under all perillaldehyde oxidation characteristic peaks is used as the overall essential oil freshness benchmark value of the plant essential oil sample.
[0054] It should be noted that by constructing a PLS loss model, information from multiple oxidation characteristic peaks is correlated with the degree of perillol loss, establishing a quantitative model that can comprehensively predict oxidation loss. This is because relying solely on a single characteristic peak or measured perillol value is insufficient to fully reflect the complex oxidation process. PLS, however, can simultaneously utilize the deviations of multiple characteristic peaks to extract latent variables related to oxidation, overcoming inter-peak correlation and noise interference. The deviation represents the degree to which the sample deviates from the fresh baseline, directly corresponding to the oxidation progress, and can be considered as model input. Then, through PLS regression, the deviation can be mapped to the perillol oxidation test content or loss rate, achieving accurate prediction of oxidation loss in unknown samples. This model also possesses cross-batch adaptability, reducing the impact of differences in the natural composition of raw materials and improving the accuracy and stability of perillol content correction.
[0055] Preferably, in some implementations of the present invention, the method for obtaining the PLS loss model is as follows: Analyze the deviation between the perillaldehyde oxidation test content and the essential oil freshness benchmark value at different oxidation test nodes in each batch; calculate the structural feature deviation of each oxidation test node in each batch; use the structural feature deviation of each oxidation test node in each batch as the independent variable of the PLS loss model, perform regression training, calculate several essential oil regression coefficients of the PLS loss model, and use the PLS loss model reconstructed from the essential oil regression coefficients as the PLS loss model for the plant essential oil samples. An example process is as follows: Preferably, in some implementations of the present invention, the method for obtaining the construction feature deviation is as follows: the standardized difference between the perillol oxidation test content and the essential oil freshness benchmark value at each oxidation test node in each batch is used as the construction feature deviation at each oxidation test node in each batch. An example process is as follows: The normalized value of the absolute value of the difference between the perillol oxidation test content and the essential oil freshness benchmark value at each oxidation test node in each batch is used as the structural characteristic deviation at each oxidation test node in each batch.
[0056] Furthermore, the feature bias is used as the independent variable of the PLS loss model for regression training. The regression coefficients of the PLS loss model are calculated and used as the regression coefficients for the essential oils. This reconstructed PLS loss model is then used as the PLS loss model for the plant essential oil samples. The process of obtaining the regression coefficients through regression training is a well-known aspect of the PLS loss model algorithm and will not be elaborated upon in this embodiment. Please refer to [link to relevant documentation]. Figure 5 It shows a schematic diagram of the batch cross-validation results of the PLS loss model; please refer to [link / reference]. Figure 6 It shows a schematic diagram of the predicted residual distribution of the PLS loss model.
[0057] Furthermore, the original perillol content and chromatogram of the plant essential oil sample to be tested are input into the PLS loss model to obtain the loss rate of the plant essential oil sample to be tested; the inverse proportional normalized value of the original perillol content and the loss rate of the plant essential oil sample to be tested is taken as the true perillol content of the plant essential oil sample to be tested.
[0058] It should be noted that the embodiments adopt The model is used to represent the inverse proportional relationship and for normalization processing. As input to the model, implementers can choose between an inverse proportional function and a normalization function based on the actual situation.
[0059] This concludes the embodiment.
[0060] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A method for detecting perillol content in natural plant essential oils, characterized in that, The method includes the following steps: Obtain the original perillol content and chromatogram of each batch of plant essential oil samples, and obtain the original perillol content and chromatogram of the plant essential oil sample to be tested; the chromatogram contains multiple chromatographic peaks, and each chromatographic peak corresponds to a chromatographic value; Oxidation test nodes were defined, and continuous oxidation tests were conducted on plant essential oil samples from each batch to obtain the perillol oxidation test content and oxidation chromatogram at different oxidation test nodes for each batch. Compare the changes in perillaldehyde content during oxidation testing with the original perillaldehyde content, and calculate the perillaldehyde loss rate at each oxidation testing node; analyze the alignment of peak values in the oxidation chromatograms of different batches at the same oxidation testing node, and select several candidate peaks for each batch from the chromatographic peaks; Within the overall batch, compare the change between the stability value and the average value of the same candidate peak in the chromatogram to calculate the inter-batch dispersion coefficient of the same candidate peak; compare the change between the numerical trend of the loss rate of perillaldehyde of the same candidate peak and the stability value in the chromatogram to calculate the oxidation sensitivity coefficient of the same candidate peak; based on the inter-batch dispersion coefficient and the oxidation sensitivity coefficient, select several perillaldehyde oxidation characteristic peaks from the candidate peaks. The stability of the overall chromatographic values of the perillol oxidation characteristic peaks was comprehensively analyzed, and the baseline value of the overall essential oil freshness of the plant essential oil samples was calculated. Based on the deviation between the perillol oxidation test content at different oxidation test nodes in each batch and the baseline value of essential oil freshness, a PLS loss model was constructed, and the perillol content of the plant essential oil samples to be tested was detected to obtain the true perillol content of the plant essential oil samples to be tested.
2. The method for detecting perillaldehyde content in natural plant essential oils according to claim 1, characterized in that, The method for obtaining the perillaldehyde oxidation test content and oxidation chromatogram is as follows: Plant essential oil samples from the same batch were divided into several continuous oxidation test samples. Several time monitoring points were preset for each continuous oxidation test sample as oxidation test nodes. The original perillol content at each oxidation test node was recorded and used as the perillol oxidation test content at each oxidation test node. Chromatographic detection was performed on the continuous oxidation test samples under each oxidation test node to obtain the chromatogram of each oxidation test node, which was used as the oxidation chromatogram.
3. The method for detecting perillol content in natural plant essential oils according to claim 1, characterized in that, The method for obtaining the perillaldehyde loss rate is as follows: At the same oxidation test node, the standardized difference between the perillol oxidation test content and the original perillol test content is taken as the perillol loss rate at the same oxidation test node.
4. The method for detecting perillol content in natural plant essential oils according to claim 1, characterized in that, The method for obtaining the candidate peak is as follows: The coordinate space of the oxidation chromatograms of different batches at the same oxidation test node is superimposed, and the chromatographic peaks with the vertical axis values that are less than the preset vertical axis difference threshold are used as candidate peaks for different batches.
5. The method for detecting perillol content in natural plant essential oils according to claim 1, characterized in that, The method for obtaining the batch-to-batch dispersion coefficient is as follows: The standard deviation of the chromatographic values of the same candidate peak in all chromatograms is used as the initial sample standard deviation of the same candidate peak; the mean of the chromatographic values of the same candidate peak in all chromatograms is used as the initial mean of the chromatographic response of the same candidate peak; and the ratio mapping result of the initial sample standard deviation and the initial mean of the chromatographic response is used as the inter-batch dispersion coefficient of the same candidate peak.
6. The method for detecting perillol content in natural plant essential oils according to claim 5, characterized in that, The method for obtaining the oxidation sensitivity coefficient is as follows: Using the perillaldehyde loss rate as the oxidation horizontal axis and the difference in chromatographic values between the chromatogram and the oxidation chromatogram of the same candidate peak as the oxidation vertical axis, a two-dimensional space for the oxidation characteristics of perillaldehyde was constructed using the oxidation horizontal and vertical axes. All candidate peaks were input into the two-dimensional space for oxidation characteristics to generate several oxidation coordinate points. All oxidation coordinate points were fitted to calculate the trend slope of the perillaldehyde loss rate of the same candidate peak. The ratio mapping result of the perillaldehyde loss rate trend slope to the initial sample standard deviation was used as the oxidation sensitivity coefficient of the same candidate peak.
7. The method for detecting perillaldehyde content in natural plant essential oils according to claim 1, characterized in that, The method for obtaining the characteristic peak of perillaldehyde oxidation is as follows: By setting a preset threshold for the inter-batch dispersion coefficient, several candidate peaks of natural differential essential oils were selected. By setting a preset threshold for the oxidation sensitivity coefficient, several characteristic peaks of perillyl alcohol oxidation were selected.
8. The method for detecting perillol content in natural plant essential oils according to claim 1, characterized in that, The method for obtaining the oil freshness benchmark value is as follows: The standard deviation of the chromatographic values of all perillaldehyde oxidation characteristic peaks was used as the benchmark value for the overall freshness of the plant essential oil samples.
9. The method for detecting perillol content in natural plant essential oils according to claim 1, characterized in that, The method for obtaining the PLS loss model is as follows: The deviation between the perillol oxidation test content and the essential oil freshness benchmark value at different oxidation test nodes in each batch was analyzed, and the structural characteristic deviation of each oxidation test node in each batch was calculated. The structural feature deviation of each oxidation test node in each batch is used as the independent variable of the PLS loss model for regression training. Several essential oil regression coefficients of the PLS loss model are calculated, and the PLS loss model reconstructed from the essential oil regression coefficients is used as the PLS loss model for plant essential oil samples.
10. The method for detecting perillol content in natural plant essential oils according to claim 9, characterized in that, The method for obtaining the construction feature deviation is as follows: The standardized difference between the perillol oxidation test content at each oxidation test node in each batch and the essential oil freshness benchmark value is used as the structural characteristic deviation at each oxidation test node in each batch.