A method for detecting benzethonium chloride in food using ultra-high performance liquid chromatography-tandem mass spectrometry

Abstract

The present invention relates to the field of component detection technology, and in particular to a method for detecting benzethonium chloride in food using ultra-high performance liquid chromatography-tandem mass spectrometry. The method comprises the following steps: extracting a food sample from the food to be tested, and pre-treating the food sample using liquid-liquid extraction and solid-phase extraction methods to obtain a pre-treated liquid sample; concentrating and dissolving the pre-treated liquid sample to obtain a sample mixed solution; performing mass spectrometry analysis on the sample mixed solution using ultra-high performance liquid chromatography-tandem mass spectrometry to obtain state information of characteristic ion signals of benzethonium chloride; obtaining an estimated concentration of benzethonium chloride based on the state information of the characteristic ion signals of benzethonium chloride; and obtaining a final benzethonium chloride concentration by introducing a dynamic ion response model and combining a recursive optimization algorithm. The method solves the technical problem that the traditional method for detecting harmful substances in food has low detection accuracy and poor sensitivity for benzethonium chloride components in food testing.

Description

Technical Field

[0001] The present invention relates to the technical field of component detection, and in particular to a method for detecting benzethonium chloride in food by utilizing ultra-high performance liquid chromatography-tandem mass spectrometry. Background Art

[0002] Benzethonium chloride is a chemical commonly used in pharmaceuticals and disinfectants. Because it can enter the food chain as a food additive or drug residue in certain situations, its detection in food is of great importance for food safety. While benzethonium chloride, a chemical, typically contains low levels of residues in food, its potential health risks necessitate precise quantitative detection. However, food samples often contain a variety of complex components, and these matrix components can interfere with the separation and analysis of target compounds, making detection more challenging, especially at lower concentrations.

[0003] Traditional methods for detecting harmful substances in food, such as gas chromatography (GC) and liquid chromatography (HPLC), can effectively perform analysis in some cases. However, the detection of benzethonium chloride in complex food matrices often faces the following challenges: First, water-soluble and fat-soluble substances in the food matrix may interact with the target substance, making separation difficult; second, the concentration of benzethonium chloride in food is generally low, and traditional methods for detecting harmful substances in food cannot achieve the required sensitivity; finally, traditional methods for detecting harmful substances in food are highly interfering with complex samples and are prone to signal noise, affecting the accuracy of detection results. Summary of the Invention

[0004] The invention provides a method for detecting benzethonium chloride in food by utilizing ultra-high performance liquid chromatography-tandem mass spectrometry, so as to solve the technical problem that in food detection, traditional methods for detecting harmful substances in food have low detection accuracy and poor sensitivity for benzethonium chloride components.

[0005] The present invention discloses a method for detecting benzethonium chloride in food by ultra-high performance liquid chromatography-tandem mass spectrometry, which specifically includes the following technical solutions:

[0006] A method for detecting benzethonium chloride in food using ultra-high performance liquid chromatography-tandem mass spectrometry comprises the following steps:

[0007] S1. Extract food samples from the food to be tested and pre-treat the food samples using liquid-liquid extraction and solid-phase extraction methods to obtain pre-treated liquid samples; concentrate and dissolve the pre-treated liquid samples to obtain a sample mixed solution;

[0008] S2. Perform mass spectrometry analysis on the sample mixture solution using ultra-performance liquid chromatography-tandem mass spectrometry to obtain state information of the characteristic ion signal of benzethonium chloride; obtain an estimated concentration of benzethonium chloride based on the state information of the characteristic ion signal of benzethonium chloride; and optimize the estimated concentration of benzethonium chloride by introducing a dynamic ion response model in combination with a recursive optimization algorithm to obtain a final benzethonium chloride concentration.

[0009] Preferably, the S1 specifically includes:

[0010] In the liquid-liquid extraction process, the food sample is mixed with an organic solvent and extracted using a separatory funnel. The organic solvent containing benzethonium chloride is separated and collected by standing and stratifying to obtain a liquid sample after liquid-liquid extraction; the liquid sample after liquid-liquid extraction is subjected to solid phase extraction to enrich benzethonium chloride to obtain a pre-treated liquid sample.

[0011] Preferably, the S1 specifically includes:

[0012] The pre-treated liquid sample is concentrated to obtain a concentrated liquid sample; and the concentrated liquid sample is dissolved to obtain a sample mixed solution.

[0013] Preferably, the S2 specifically includes:

[0014] The sample mixed solution was injected into an ultra-high performance liquid chromatography system for liquid chromatography separation, and the effluent after liquid chromatography separation was introduced into a tandem mass spectrometry system. After ionization using an electrospray ionization source, mass spectrometry analysis was performed using a selective reaction monitoring mode to obtain state information of the characteristic ion signal of benzethonium chloride.

[0015] Preferably, the S2 specifically includes:

[0016] Based on the characteristic ion signal intensity of benzethonium chloride, an estimated concentration value of benzethonium chloride is obtained; based on the estimated concentration value of benzethonium chloride and the characteristic ion signal intensity of benzethonium chloride, a response factor and an exponential decay term are introduced to construct a dynamic ion response model; the characteristic ion signal intensity of benzethonium chloride comes from state information of the characteristic ion signal of benzethonium chloride.

[0017] Preferably, the S2 specifically includes:

[0018] The parameters in the dynamic ion response model were fitted and solved by the least squares method combined with the actual signal intensity of the characteristic ion of benzethonium chloride.

[0019] Preferably, the S2 specifically includes:

[0020] In the implementation process of the recursive optimization algorithm, a learning rate is introduced based on the characteristic ion signal intensity of benzethonium chloride to update the estimated value of benzethonium chloride concentration to obtain an updated estimated value of benzethonium chloride concentration.

[0021] Preferably, the S2 specifically includes:

[0022] Based on the updated estimated value of benzethonium chloride concentration, an error correction mechanism is introduced to correct the estimated value of benzethonium chloride concentration through the error correction factor to obtain the final benzethonium chloride concentration.

[0023] The beneficial effects of the technical solution of the present invention are:

[0024] 1. The combination of ultra-high performance liquid chromatography (UHPLC) and tandem mass spectrometry (MS / MS) enables the effective separation of benzethonium chloride molecules in complex matrices and accurate quantitative analysis. In particular, when using the selected reaction monitoring (SRM) mode, the characteristic ions (parent ion and daughter ion pairs) of benzethonium chloride can be precisely monitored, greatly improving the sensitivity and selectivity of detection. The introduction of a dynamic ion response model and recursive optimization algorithm enables more accurate estimation of benzethonium chloride concentration, reduces the interference of matrix effects on the analytical results, and improves the reliability of quantitative analysis.

[0025] 2. The combined use of liquid-liquid extraction and solid-phase extraction significantly improves the recovery rate of benzethonium chloride. During the extraction process, repeated extraction operations further increase the recovery efficiency of benzethonium chloride, and solid-phase extraction further purifies the food sample, removes interfering components, and improves the purity of benzethonium chloride. By combining multiple extracts and concentrating the food sample, benzethonium chloride is effectively enriched, providing a higher concentration sample for subsequent chromatographic analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention provides a flow chart of a method for detecting benzethonium chloride in food using ultra-high performance liquid chromatography-tandem mass spectrometry. DETAILED DESCRIPTION

[0027] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0028] Unless defined otherwise, 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 belongs.

[0029] The following describes in detail a method for detecting benzethonium chloride in food using ultra-high performance liquid chromatography-tandem mass spectrometry provided by the present invention in conjunction with the accompanying drawings.

[0030] Refer to the attached Figure 1 , which shows a flow chart of a method for detecting benzethonium chloride in food using ultra-high performance liquid chromatography-tandem mass spectrometry provided by one embodiment of the present invention, the method comprising the following steps:

[0031] S1. Extract food samples from the food to be tested and pre-treat the food samples using liquid-liquid extraction and solid-phase extraction methods to obtain pre-treated liquid samples; concentrate and dissolve the pre-treated liquid samples to obtain a sample mixed solution;

[0032] Based on the specific testing needs and the type of food to be tested, select an appropriate sampling method to extract food samples from the food to be tested. For solid foods (such as meat, vegetables, bread, etc.), sample from multiple different parts (e.g., uniform sampling) to ensure representative samples, with a sample size of approximately 10 grams for each solid food. For liquid foods (such as juice, beverages, soups, etc.), directly take a 10mL liquid sample. Especially for viscous liquids, ensure that the sample is collected evenly. After sampling, the food sample should be quickly placed in a container and stored at a low temperature to avoid degradation of benzethonium chloride or other ingredients. Use a non-contaminated container when sampling, and ensure that the food sample is representative of the overall properties of the food to be tested.

[0033] Specifically, the solid sample is ground into a uniform solid mixture using a homogenizer, and then the solid mixture is dissolved using a dissolving reagent to obtain a liquid sample after the solid is dissolved, thereby helping to release benzethonium chloride from the sample matrix. The purpose of this step is to present the food sample in a liquid state. The choice of the dissolving reagent is determined based on expert experience according to the specific scenario and is not limited here.

[0034] Furthermore, in order to improve the accuracy and sensitivity of benzethonium chloride detection in food samples and ensure that benzethonium chloride can be efficiently separated and extracted from complex matrices and interfering components can be eliminated during the pretreatment process of food samples, liquid-liquid extraction and solid-phase extraction methods were used to pretreat the food samples to obtain pretreated samples;

[0035] The specific process of pretreatment includes: liquid-liquid extraction of food samples (liquid samples or liquid samples after solid dissolution); during the liquid-liquid extraction process, the food sample (aqueous phase) and the organic solvent (organic phase) are mixed in a 1:1 volume ratio and then extracted using a separatory funnel; the core of the above process is to fully stir the mixture of food sample and organic solvent so that the food sample can be effectively separated into layers; each extraction operation lasts 15-20 minutes to ensure that benzethonium chloride can be fully dissolved in the organic solvent. After the extraction is completed, the organic phase containing benzethonium chloride is separated and collected by standing and stratification; the choice of the organic solvent is set according to the specific scenario through expert experience and is not limited here;

[0036] In order to improve the recovery rate of benzethonium chloride, it is necessary to repeatedly extract the remaining aqueous phase with a fresh organic solvent, and combine the organic phase containing benzethonium chloride obtained by the second or more extractions with the organic phase containing benzethonium chloride obtained by the first extraction to obtain a liquid sample after liquid-liquid extraction, thereby providing a higher concentration of benzethonium chloride for subsequent processing;

[0037] Furthermore, the liquid sample after liquid-liquid extraction is subjected to solid phase extraction (SPE) to remove residual impurities and enrich benzethonium chloride to obtain a pre-treated liquid sample; the solid phase extraction process includes: first, selecting a C18 solid phase extraction column with high adsorption efficiency for non-polar molecules and pre-treating it to obtain a pre-treated solid phase extraction column, wherein the pre-treatment is to rinse the extraction column with an appropriate amount of organic solvent (such as methanol) and water to remove any potential pollutants and residues, which is a technical means well known to those skilled in the art and will not be described in detail here; the amount of the organic solvent used is determined according to the specific application scenario by Expert experience determines the volume. Next, the liquid sample, after liquid-liquid extraction, is slowly passed through a pretreated solid-phase extraction column. During this process, the benzethonium chloride is fully adsorbed by the pretreated solid-phase extraction column material, while other interfering substances are retained within the column. After extraction, the solid-phase extraction column is washed with a mixture of water and a weakly polar solvent (such as a water-methanol mixture) to further remove water-soluble impurities and other interfering substances. Finally, to elute the benzethonium chloride from the solid-phase extraction column, a more polar solvent (such as acetonitrile or methanol) is used for elution. The eluate is collected to obtain the pretreated liquid sample. The volume of the solvent is determined based on expert experience, such as between 5-10 mL.

[0038] Furthermore, the pre-treated liquid sample is concentrated according to specific application requirements to ensure the effectiveness of subsequent chromatographic analysis; the concentration method can be nitrogen purging and concentration, or using a rotary evaporator to evaporate the solvent until the volume of the pre-treated liquid sample is concentrated to a required range to obtain a concentrated liquid sample; the methods used for the concentration treatment are technical means well known to those skilled in the art and are not described in detail here; the required range is specifically set according to specific application requirements and is not limited here;

[0039] The concentrated liquid sample is dissolved again to obtain a sample mixed solution; a commonly used dissolving solvent is a water-methanol mixed solution. At this point, the concentration of the sample mixed solution should meet the requirements of subsequent ultra-high performance liquid chromatography analysis.

[0040] S2. Perform mass spectrometry analysis on the sample mixture solution using ultra-performance liquid chromatography-tandem mass spectrometry to obtain state information of the characteristic ion signal of benzethonium chloride; obtain an estimated concentration of benzethonium chloride based on the state information of the characteristic ion signal of benzethonium chloride; and optimize the estimated concentration of benzethonium chloride by introducing a dynamic ion response model in combination with a recursive optimization algorithm to obtain a final benzethonium chloride concentration.

[0041] The sample mixture solution was subjected to mass spectrometry analysis using ultra-high performance liquid chromatography-tandem mass spectrometry. The specific process is as follows:

[0042] The sample mixture solution was sent to an ultra-high performance liquid chromatography (UHPLC) system and separated and analyzed using a reversed-phase C18 chromatographic column. The mobile phase was set to a gradient mixture of water (or 0.1% formic acid) and acetonitrile. Initially, the ratio of water to acetonitrile was 70:30 (v / v). As time progressed, the ratio of acetonitrile gradually increased until it reached 30:70 (v / v). The flow rate of the mobile phase was set to 0.4 mL / min, and the column temperature was set to 30°C to ensure optimal separation.

[0043] The sample mixture is injected into the ultra-high performance liquid chromatography system, and the injection volume is set according to the specific scenario, such as 5μL, to ensure an appropriate peak area and avoid overloading the chromatographic column. During the liquid chromatography separation process, benzethonium chloride is gradually separated from other chemical components in the matrix, ensuring that interfering substances in subsequent mass spectrometry analysis are minimized;

[0044] Subsequently, the effluent after liquid chromatography separation was introduced into a tandem mass spectrometry (MS / MS) system for further analysis. In the mass spectrometry analysis, an electrospray ionization source (ESI) was used for ionization, and the positive ion mode was selected to improve the ionization efficiency of benzethonium chloride. The parameters of the electrospray ionization source were set as follows: spray voltage of +3500 V, source temperature of 350°C, and auxiliary gas flow rate of 10 L / min. The above settings ensured that benzethonium chloride could be efficiently converted into ions in the electrospray ionization source and could maintain a high ion intensity when entering the mass spectrometry detection stage;

[0045] After ionization, mass spectrometry analysis is performed using an existing mass spectrometer, and the mass spectrometry analysis adopts the selected reaction monitoring (SRM) mode. In the selected reaction monitoring mode, the parent ion mass / charge ratio (m / z) of benzethonium chloride is set to 284.2, and the daughter ion mass / charge ratio is set to 194.1. Selecting the SRM mode can accurately monitor the characteristic ions of benzethonium chloride to reduce background interference and improve sensitivity and selectivity. The collision energy is set to 35eV to ensure that the parent ion of benzethonium chloride is fully fragmented in the collision cell, thereby generating daughter ions with strong signals. The mass spectrometer measures and records the state information of the characteristic ion signal of benzethonium chloride, that is, the state information of the parent ion and daughter ion of benzethonium chloride, through its own automatic acquisition function. The mass spectrometry analysis method is a technical means well known to those skilled in the art and will not be described in detail here.

[0046] Furthermore, in order to effectively improve the accuracy and sensitivity of benzethonium chloride concentration determination, a dynamic ion response model was introduced based on the state information of the characteristic ion signal of benzethonium chloride, and an optimization analysis was performed in combination with a recursive optimization algorithm to obtain the final benzethonium chloride concentration;

[0047] The dynamic ion response model is based on the concentration-response relationship in biochemistry and is obtained by fitting the experimental data by the least squares method; the experimental data are the characteristic ion signal intensity of benzethonium chloride and the estimated concentration of benzethonium chloride. In order to avoid the influence of dimensional inconsistency, the experimental data are all data after standardization. The method of standardization is a technical means well known to those skilled in the art and will not be described in detail here; the characteristic ion signal intensity of benzethonium chloride comes from the state information of the characteristic ion signal of benzethonium chloride; the estimated concentration of benzethonium chloride is obtained by the standard curve method based on the characteristic ion signal intensity of benzethonium chloride; the standard curve method is a technical means well known to those skilled in the art and will not be described in detail here; the dynamic ion response model can be expressed as:

[0048] ;

[0049] ;

[0050] in, and Respectively expressed in The signal intensities of the parent ion and daughter ion of benzethonium chloride at the time instant are obtained from the state information of the characteristic ion signal of benzethonium chloride; yes Estimated benzethonium chloride concentration at time t; and is a constant coefficient proportional to the concentration; and They represent the nonlinear relationship coefficients between the estimated benzethonium chloride concentration and the signal intensity of the parent ion and the daughter ion, respectively, reflecting the degree of influence of the benzethonium chloride concentration on the characteristic ion signal intensity; and is the attenuation coefficient, which describes the attenuation process of the characteristic ion signal intensity over time; Indicates The relative time variable of the moment, , is a reference time variable, determined according to expert experience, such as the total experimental time, mass spectrometry acquisition cycle, etc.; the dynamic ion response model represents the relationship between the concentration of benzethonium chloride and the characteristic ion signal intensity through a power function, and introduces an exponential decay term to reflect the time-dependent decay of the mass spectrometer response; further, the least squares method is used to construct the objective function , for unknown parameters in the dynamic ion response model Perform fitting to obtain the best fitting parameters. The specific formula of the objective function is:

[0051] ;

[0052] in, is the set of parameters to be fitted; and Respectively expressed in The signal intensity of the benzethonium chloride parent ion and daughter ion at the moment is the actual signal intensity extracted from the above experimental data. The above objective function is minimized by an optimization algorithm such as a genetic algorithm to obtain the parameters of the optimal dynamic ion response model, thereby achieving modeling of the nonlinear relationship between the benzethonium chloride concentration and the characteristic ion signal intensity; the genetic algorithm is a technical means well known to those skilled in the art and will not be described in detail here;

[0053] After the modeling is completed, due to the possible presence of noise, systematic errors, and experimental errors in mass spectrometry analysis, a single model fitting cannot obtain the best results. Therefore, based on the characteristic ion signal intensity of benzethonium chloride, a recursive optimization algorithm is introduced to gradually optimize the estimated benzethonium chloride concentration to obtain the final benzethonium chloride concentration. The specific implementation process of the recursive optimization algorithm is as follows:

[0054] Set in The estimated concentration of benzethonium chloride at time , use the recursive optimization formula to update the estimated value of benzethonium chloride concentration to obtain the updated estimated value of benzethonium chloride concentration. Based on the dynamic system optimization method and nonlinear regression algorithm, the recursive optimization formula is obtained:

[0055] ;

[0056] in, is Estimated benzethonium chloride concentration at time t; For Estimated benzethonium chloride concentration at time t; Is the learning rate or step size factor, which is used to control the speed of recursive update and determines the adjustment range of the estimated value of benzethonium chloride concentration at each update. It is set according to expert experience and the reference value range is , the value can be 0.1; Indicates The relative time variable of the moment, ; It is at the moment The measured parent ion signal intensity of benzethonium chloride is obtained by mass spectrometry analysis; the dynamic system optimization method and nonlinear regression algorithm are both technical means well known to those skilled in the art and will not be described in detail here;

[0057] ;

[0058] in, Indicates The corrected benzethonium chloride concentration value is the final benzethonium chloride concentration; Is the error correction factor, which represents the factor used to adjust the current benzethonium chloride concentration estimation error. It is adjusted according to the system error through expert experience. The reference value range is , such as 0.3; is The signal intensity of the daughter ion of benzethonium chloride measured at each moment; is The parent ion signal intensity of benzethonium chloride measured at each moment; The term indicates that over time, the signals of the parent ion and daughter ion of benzethonium chloride will be affected by factors such as instrument drift and matrix effect, resulting in a change in the signal intensity ratio, which serves as the basis for correcting the estimated value of the benzethonium chloride concentration. An error correction factor is further introduced to quantify the impact of the change in the current signal intensity ratio on the estimated value of the benzethonium chloride concentration. By adjusting the correction factor, the deviation of the benzethonium chloride concentration can be effectively corrected. is the error correction term;

[0059] In summary, a method for detecting benzethonium chloride in food using ultra performance liquid chromatography-tandem mass spectrometry was completed.

[0060] The order in which the embodiments of the invention are presented is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0061] 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.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for detecting benzethonium chloride in food using ultra performance liquid chromatography-tandem mass spectrometry, characterized in that, The following steps are involved: S1. Extract food samples from the food to be tested and pre-treat the food samples using liquid-liquid extraction and solid-phase extraction methods to obtain pre-treated liquid samples; concentrate and dissolve the pre-treated liquid samples to obtain a sample mixed solution; S2. performing mass spectrometry analysis on the sample mixed solution using ultra-high performance liquid chromatography-tandem mass spectrometry, injecting the sample mixed solution into an ultra-high performance liquid chromatography system for liquid chromatography separation, and introducing the effluent after the liquid chromatography separation into the tandem mass spectrometry system, ionizing it using an electrospray ionization source, and performing mass spectrometry analysis in a selective reaction monitoring mode to obtain state information of the characteristic ion signal of benzethonium chloride; obtaining an estimated concentration of benzethonium chloride based on the characteristic ion signal intensity of benzethonium chloride derived from the state information of the characteristic ion signal of benzethonium chloride; introducing a response factor and an exponential decay term based on the estimated concentration of benzethonium chloride and the characteristic ion signal intensity of benzethonium chloride to construct a dynamic ion response model; fitting and solving the parameters in the dynamic ion response model using the least squares method in combination with the actual signal intensity of the characteristic ion of benzethonium chloride; By introducing a dynamic ion response model and combining it with a recursive optimization algorithm, the estimated concentration of benzethonium chloride was optimized to obtain the final benzethonium chloride concentration. The dynamic ion response model is expressed as: ； ； in, and Respectively expressed in Signal intensity of benzethonium chloride parent ion and daughter ion at time t; yes Estimated benzethonium chloride concentration at time t; and is a constant coefficient proportional to the concentration; and represent the nonlinear relationship coefficients between the estimated concentration of benzethonium chloride and the signal intensity of the parent ion and product ion, respectively; and is the attenuation coefficient; Indicates The relative time variable of the moment.

2. a method for detecting benzethonium chloride in food by ultra performance liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that, Said S1 specifically includes: In the liquid-liquid extraction process, the food sample is mixed with an organic solvent and extracted using a separatory funnel. The organic solvent containing benzethonium chloride is separated and collected by standing and stratifying to obtain a liquid sample after liquid-liquid extraction; the liquid sample after liquid-liquid extraction is subjected to solid phase extraction to enrich benzethonium chloride to obtain a pre-treated liquid sample.

3. a method for detecting benzethonium chloride in food by ultra performance liquid chromatography-tandem mass spectrometry according to claim 2, characterized in that, Said S1 specifically includes: The pre-treated liquid sample is concentrated to obtain a concentrated liquid sample; and the concentrated liquid sample is dissolved to obtain a sample mixed solution.

4. A method for detecting benzethonium chloride in food by ultra performance liquid chromatography-tandem mass spectrometry according to claim 1, wherein Said S2 specifically includes: In the implementation process of the recursive optimization algorithm, a learning rate is introduced based on the characteristic ion signal intensity of benzethonium chloride to update the estimated value of benzethonium chloride concentration to obtain an updated estimated value of benzethonium chloride concentration.

5. a method for detecting benzethonium chloride in food by ultra performance liquid chromatography-tandem mass spectrometry according to claim 4, characterized in that, Said S2 specifically includes: Based on the updated estimated value of benzethonium chloride concentration, an error correction mechanism is introduced to correct the estimated value of benzethonium chloride concentration through the error correction factor to obtain the final benzethonium chloride concentration.

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