A method for solving apparent reaction kinetic parameters of triple excited state DOM by LFP data

Abstract

The application discloses a kind of LFP data solving triple excited state DOM apparent reaction kinetics parameter method, it is related to spectral analysis technical field, and its technical solution key points include the following specific steps: collecting the relationship of absorbance change with time when the transient absorption data of target organic matter and dissolved organic matter system reaction of different initial concentration is obtained;Determine initial reaction time, mark the time corresponding to the maximum absorbance as the initial reaction time, generate updated time series and corresponding absorbance data according to the initial reaction time;The updated absorbance data is identified and corrected to obtain the processed absorbance data;The processed absorbance data is processed to obtain the denoised transient absorption decay curve;Effect is to reduce the uncertainty caused by parameter coupling in complex system, improve the stability and applicability of kinetic parameter solving, facilitate the kinetic study of pollutant photochemical conversion process in natural water body.

Description

Technical Field

[0001] This invention relates to the field of spectroscopic analysis technology, and more specifically, to a method for solving the apparent reaction kinetic parameters of triple excited-state DOM from LFP data. Background Technology

[0002] Dissolved organic matter (DOM) is widely present in natural water bodies and is an important active component controlling the photochemical transformation of pollutants in the aquatic environment. Under light conditions, DOM can form triplet excited states (…). 3 SENE * It is a highly reactive intermediate mainly composed of [missing information], and further reacts with organic pollutants through electron transfer, energy transfer, or free radical reactions, thereby significantly affecting the environmental fate of pollutants. Currently, 3 SENS * The reaction kinetic parameters (such as excited state lifetime, bimolecular reaction rate constant, etc.) are the core indicators describing its reactivity.

[0003] Laser flash photolysis (LFP) is one of the main methods for studying the dynamics of transient species. It characterizes excited-state species by recording the decay process of transient absorption signals over time. This method has been widely applied to determine the excited-state lifetime and reaction rate constant in single-compound systems. In simple systems, analysis is typically based on the following relationship: excited-state decay follows pseudo-first-order kinetics; and under the condition of adding a quencher, the bimolecular reaction rate constant is solved through the linear relationship between the apparent rate constant and the quencher concentration.

[0004] However, due to the transformation product SENS*, SENS· - Usually with SENS * The absorption spectra of the two molecules are highly overlapping, but their decay kinetics are different. Therefore, traditional fitting methods cannot effectively distinguish between them, resulting in deviations in the fitting of the concentration and lifetime of SENS*, which in turn affects the judgment of the reaction rate constant between organic matter and SENS*. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for solving the apparent reaction kinetic parameters of triple excited-state DOM using LFP data.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for solving the apparent reaction kinetic parameters of triple excited-state DOM using LFP data, the method comprising the following specific steps:

[0008] Transient absorption data were collected during the reaction of target organic compounds with dissolved organic matter at different initial concentrations to obtain the relationship between absorbance and time.

[0009] Determine the initial reaction time, marking the time when the absorbance reaches its maximum value as the initial reaction time, and generate an updated time series and corresponding absorbance data based on the initial reaction time.

[0010] The updated absorbance data is identified and corrected to obtain the processed absorbance data.

[0011] The processed absorbance data is processed to obtain the denoised transient absorption attenuation curve;

[0012] An apparent decay kinetic model was established based on the reaction relationship between the triple excited state and the target organic matter, and corresponding kinetic equations were constructed according to different target organic matter concentrations.

[0013] Based on the kinetic equation, multiple transient absorption decay curves under different concentration conditions are jointly fitted to extract the apparent decay constant under different concentration conditions. Based on the correlation between the apparent decay constant and the concentration of the target organic compound, the self-decay rate constant of the triple excited state and its bimolecular reaction rate constant with the target organic compound are solved.

[0014] Preferably, the transient absorption data of the reaction between the target organic compound and dissolved organic matter at different initial concentrations are collected to obtain the relationship between absorbance and time, specifically including the following steps:

[0015] An aqueous solution containing dissolved organic matter is mixed with a target organic compound of known concentration. The dissolved organic matter system is instantaneously excited by a pulsed laser, and the change in absorbance over time is obtained by extracting the change in absorbance based on a transient absorption detector.

[0016] Preferably, the initial reaction time is determined by marking the time when the absorbance reaches its maximum value as the initial reaction time. An updated time series and corresponding absorbance data are then generated based on the initial reaction time, specifically including the following steps:

[0017] The moment corresponding to the maximum absorbance value in the relationship between absorbance and time is extracted as the initial reaction time t0. Based on the initial reaction time t0, the updated time series and corresponding absorbance data are obtained.

[0018] Preferably, the updated absorbance data is identified and corrected to obtain the processed absorbance data, specifically including the following steps:

[0019] Based on the updated absorbance data, the absorbance difference between multiple consecutive measurement intervals is determined, and areas with absorbance differences less than a preset threshold are marked as abnormal areas.

[0020] The start time t1 and end time t2 of the abnormal region are collected. Using the total time corresponding to several measurement intervals as Δt, the maximum absorbance A is extracted within (t1-Δt, t1). max1 and the corresponding time t max1 Extract the maximum absorbance A within (t2, t2+Δt). max2 and the corresponding time t max2 Delete t max1 To t max2 All measurements between;

[0021] Based on (t) max1 A max1 ) and (t max2 A max2 A linear equation is constructed to represent time and absorbance. The absorbance of the deleted region is then filled in according to the measurement interval to obtain the processed absorbance data.

[0022] Preferably, the processed absorbance data is processed to obtain a denoised transient absorption attenuation curve, specifically including the following steps:

[0023] The processed absorbance data is smoothed using the Savitzky-Golay filter, and the transient absorption attenuation curve after denoising is obtained by setting the filter window length and polynomial order based on the data sampling interval.

[0024] Preferably, a set of differential equations is constructed based on the spontaneous decay reaction of the triple excited state, the reaction of the triple excited state with the target organic compound to generate a reduced product, and the subsequent transformation reaction of the reduced product;

[0025] ;

[0026] in, Absorbance For compounds concentration, compound concentration, and Compounds and The corresponding absorption coefficient.

[0027] Preferably, the system of differential equations is as follows:

[0028] ;

[0029] Where x is the initial concentration of the DOM excited state SENS*, and y is The concentrations are: m is the initial concentration of the substrate chemical TC; k0 is the SENS* self-decay rate constant; k1 is the bimolecular reaction rate constant between SENS* and the target organic compound; k2 is the conversion rate constant of the reduced product; z is the total absorbance; and a is... The absorption coefficient, b is The absorption coefficient.

[0030] Preferably, an apparent decay kinetic model is established based on the reaction relationship between the triple excited state and the target organic compound, and corresponding kinetic equations are constructed according to different target organic compound concentrations. Specifically, this includes the following steps:

[0031] If the concentration of the target organic compound corresponding to the transient absorption decay curve is higher than the triplet excited state concentration, the transient absorption signal decay process is described by the apparent kinetic model in pseudo-first-order reaction form. The correlation between the apparent decay rate constant K and the concentration of the target organic compound m is obtained, and the calculation formula is as follows:

[0032] ;

[0033] Where K is the apparent decay rate constant, m is the initial concentration of the substrate chemical TC, k0 is the SENS* self-decay rate constant, and k1 is the bimolecular reaction rate constant between SENS* and the target organic compound.

[0034] Preferably, based on the kinetic equation, multiple sets of transient absorption decay curves under different concentration conditions are jointly fitted to extract the apparent decay constant under different concentration conditions. Based on the correlation between the apparent decay constant and the concentration of the target organic compound, the self-decay rate constant of the triplet excited state and its bimolecular reaction rate constant with the target organic compound are solved. Specifically, this includes the following steps:

[0035] Based on the correlation between the apparent decay rate constant K and the target organic matter concentration m, the transient absorption decay curves under different target organic matter concentrations are input into a single exponential model for fitting. The single exponential model is as follows:

[0036] ;

[0037] Where z(t) is the transient absorbance, A is the amplitude parameter, K is the apparent decay rate constant, and B is the baseline parameter. The apparent decay rate constant K values ​​under different concentration conditions are obtained by fitting the transient absorption decay curves of each group using the nonlinear least squares method.

[0038] Preferably, it further includes:

[0039] Based on the apparent decay constant K values ​​corresponding to different concentrations, a linear fit was performed with the target organic concentration m as the abscissa and the apparent decay rate constant K as the ordinate. The intercept of the linear fit corresponds to the self-decay rate constant k0 of the triple excited state, and the slope corresponds to the bimolecular reaction rate constant k1 between the triple excited state and the target organic. The reliability of the fitting results was evaluated based on the coefficient of determination, standard error, and confidence level.

[0040] Compared with existing technologies, this invention has the following advantages: by jointly analyzing transient absorption decay curves under multiple concentration conditions, it achieves stable analysis of the apparent decay rate of triplet excited states and the bimolecular reaction rate constant between the triplet excited states and the target organic matter in complex soluble organic matter systems; this method does not require direct determination of the composition of soluble organic matter or the concentration of intermediate species, reduces the uncertainty caused by parameter coupling in complex systems, improves the stability and applicability of kinetic parameter solutions, and facilitates the kinetic study of the photochemical transformation process of pollutants in natural water bodies. Attached Figure Description

[0041] Figure 1 This invention provides a schematic diagram of the original data showing the change of absorbance over time during the reaction of p-HBSA with DOM in a method for solving the apparent reaction kinetic parameters of triple excited-state DOM using LFP data;

[0042] Figure 2 This is a schematic diagram illustrating the change in absorbance over time during the reaction of p-HBSA and DOM after updating time 0 in an embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram illustrating the change in absorbance over time during the reaction of p-HBSA with DOM after discarding the first 20 sampling points in an embodiment of the present invention.

[0044] Figure 4 This is a schematic diagram showing the change in absorbance over time during the reaction of p-HBSA with DOM after smoothing in an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram showing the fitting results of absorbance change over time during the reaction of full-concentration p-HBSA with DOM in an embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram showing the relationship between the full concentration of p-HBSA and the apparent decay constant in an embodiment of the present invention. Detailed Implementation

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0048] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0049] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0050] Reference Figures 1-6 As shown.

[0051] The embodiments further illustrate the method for solving the apparent reaction kinetic parameters of triple excited-state DOM using LFP data proposed in this invention.

[0052] A method for solving the apparent reaction kinetic parameters of triple excited-state DOM using LFP data, the method comprising the following specific steps:

[0053] Transient absorption data were collected during the reaction of target organic compounds with dissolved organic matter at different initial concentrations to obtain the relationship between absorbance and time.

[0054] Determine the initial reaction time, marking the time when the absorbance reaches its maximum value as the initial reaction time, and generate an updated time series and corresponding absorbance data based on the initial reaction time.

[0055] The updated absorbance data is identified and corrected to obtain the processed absorbance data.

[0056] The processed absorbance data is processed to obtain the denoised transient absorption attenuation curve;

[0057] An apparent decay kinetic model was established based on the reaction relationship between the triple excited state and the target organic matter, and corresponding kinetic equations were constructed according to different target organic matter concentrations.

[0058] Based on the kinetic equation, multiple transient absorption decay curves under different concentration conditions are jointly fitted to extract the apparent decay constant under different concentration conditions. Based on the correlation between the apparent decay constant and the concentration of the target organic compound, the self-decay rate constant of the triple excited state and its bimolecular reaction rate constant with the target organic compound are solved.

[0059] The transient absorption data of the reaction between target organic compounds and dissolved organic matter at different initial concentrations were collected to obtain the relationship between absorbance and time. This process includes the following steps:

[0060] An aqueous solution containing dissolved organic matter is mixed with a target organic compound of known concentration. The dissolved organic matter system is instantaneously excited by a pulsed laser, and the change in absorbance over time is obtained by extracting the change in absorbance based on a transient absorption detector.

[0061] First, the system sample is prepared by mixing an aqueous solution containing dissolved organic matter with a target organic compound of known concentration to obtain the mixed solution system to be tested. Then, the dissolved organic matter in the mixed system is transiently excited by a pulsed laser. Upon laser excitation, the dissolved organic matter generates corresponding transient species, and the absorbance of the mixed system changes over time. The absorbance changes at different times are continuously collected and extracted using a transient absorption detector. The absorbance values ​​at each time point are arranged chronologically to obtain the relationship between absorbance and time, completing this stage of data acquisition. For example, the absorbance curves as a function of time are measured when p-HBSA concentrations are 1 mM, 2 mM, 2.5 mM, 3 mM, and 3.72 mM, with 7500 measurements taken at 1.6 nanosecond intervals. Additionally, data measured at 1 mM [SENS*] and 0 mM p-HBSA concentration serve as a blank control. The absorbance change over time is recorded, and the raw data is as follows: Figure 1 As shown.

[0062] Determine the initial reaction time, marking the moment when absorbance reaches its maximum value as the initial reaction time. Generate an updated time series and corresponding absorbance data based on the initial reaction time, specifically including the following steps:

[0063] The moment corresponding to the maximum absorbance value in the relationship between absorbance and time is extracted as the initial reaction time t0. Based on the initial reaction time t0, the updated time series and corresponding absorbance data are obtained.

[0064] The absorbance values ​​at all times in the relationship between absorbance and time are retrieved, and the position where the absorbance reaches the maximum value is selected. The time corresponding to this position is set and marked as the initial reaction time t0. Then, using the determined initial reaction time t0 as the time starting point, the information of the time dimension is rearranged to generate an updated time series. At the same time, the absorbance values ​​corresponding to each updated time node are matched and retained. Finally, the time series with time base correction and the corresponding absorbance data are obtained, completing the data processing of this stage.

[0065] The updated absorbance data is identified and corrected to obtain the processed absorbance data, specifically including the following steps:

[0066] Based on the updated absorbance data, the absorbance difference between multiple consecutive measurement intervals is determined, and areas with absorbance differences less than a preset threshold are marked as abnormal areas.

[0067] The start time t1 and end time t2 of the abnormal region are collected. Using the total time corresponding to several measurement intervals as Δt, the maximum absorbance A is extracted within (t1-Δt, t1). max1 and the corresponding time t max1 Extract the maximum absorbance A within (t2, t2+Δt). max2 and the corresponding time t max2 Delete t max1 To t max2 All measurements between;

[0068] Based on (t) max1 A max1 ) and (t max2 A max2 A linear equation is constructed to represent time and absorbance. The absorbance of the deleted region is then filled in according to the measurement interval to obtain the processed absorbance data.

[0069] First, the absorbance data that has been updated to reflect the time reference is processed. The absorbance difference between multiple consecutive measurement intervals is calculated. If the absorbance difference between consecutive measurement intervals within a certain region is less than a preset threshold, the region is marked as an abnormal region. Next, the start time t1 and end time t2 of the abnormal region are determined, and the total duration Δt corresponding to the measurement intervals covered by the abnormal region is calculated. Two reference intervals are selected. The first interval is from t1-Δt to t1, and the maximum absorbance value A is extracted from it. max1 and the corresponding time t max1 The second segment is the interval from t2 to t2+Δt, from which the maximum absorbance value A is extracted. max2 and the corresponding time t max2 , then t max1 With t max2 All original measurement values ​​were deleted; then the coordinates (t) were used. max1 A max1 ), (t max2 A max2 Establish a linear equation between time and absorbance. Based on the original measurement interval, calculate the absorbance value at the corresponding position through this straight line, complete the data of the deleted area, and finally obtain the complete corrected absorbance data.

[0070] For example, the maximum values ​​of the six absorbance curves occur at measurements 1874, 1875, 1875, 1859, 1859, and 1600, respectively. Taking this moment as the reaction start point 0, all preceding measurements are discarded, and time is reallocated for subsequent measurements. To reduce the impact of instrument response fluctuations and scattering signals on the dynamic fitting during the initial laser excitation phase, 20 sampling points are discarded after time 0, keeping the time series unchanged. The processed transient absorption curve is shown below. Figure 3 As shown.

[0071] Outlier detection was performed on transient absorption data, and outliers were processed. For measurement data with outliers, the outlier portions were deleted, and interpolation was used to fill in the missing data. The method for determining outlier data was that, after the reaction started, the absorbance change was less than 10 for more than 10 measurement intervals. -6 The interpolation method uses a linear interpolation method based on the nearest valid data points for repair.

[0072] The processed absorbance data is then processed to obtain the denoised transient absorption attenuation curve, specifically including the following steps:

[0073] The processed absorbance data is smoothed using the Savitzky-Golay filter, and the transient absorption attenuation curve after denoising is obtained by setting the filter window length and polynomial order based on the data sampling interval.

[0074] The processed absorbance data is smoothed using a Savitzky-Golay filter. The filter window length and polynomial order are adjusted based on the data sampling interval. For example, when the sampling interval is 1.6 ns, a window length of 10¹ and a 5th-order polynomial can be used. The smoothed data is shown below. Figure 4 As shown, the filter performs a smoothing operation on the entire absorbance time series data according to the set parameters, removes scattered noise fluctuations in the data, and finally obtains a transient absorption attenuation curve with smooth and regular trend after removing noise interference, providing a reliable data foundation for subsequent dynamic modeling and fitting.

[0075] A set of differential equations is constructed based on the spontaneous decay reaction of the triple excited state, the reaction of the triple excited state with the target organic compound to generate the reduced product, and the subsequent transformation reaction of the reduced product.

[0076] ;

[0077] in, Absorbance For compounds concentration, compound concentration, and Compounds and The corresponding absorption coefficient.

[0078] The modeling process needs to incorporate three types of reaction processes: spontaneous decay reactions occurring within the triplet excited state itself, reactions between the triplet excited state and the target organic compound to generate reduced products, and reactions involving further transformation of the reduced products. A set of corresponding differential equations is constructed based on these three types of reactions. Simultaneously, the total absorbance of the system is defined as a decomposed value. The measured total absorbance is obtained by superimposing two absorbance contributions: one from the triplet excited state, which is the product of the triplet excited state concentration and its own absorbance coefficient; and the other from the reduced product, which is the product of the reduced product concentration and its own absorbance coefficient. The corresponding relationship is as follows: , in the formula Represents total absorbance. Represents the concentration of triplet excited states. Represents the absorption coefficient of the triplet excited state. Represents the concentration of the reduced product. This represents the absorbance coefficient of the reduced product. For example, based on multiple decay curves obtained from different p-HBSA concentrations in the experiment, the corresponding concentration conditions can be substituted to build a dedicated kinetic equation, decompose the contribution of each of the two substances to the total absorbance, accurately restore the kinetic changes of the entire reaction under different substrate concentrations, and support the subsequent fitting and solution of rate parameters.

[0079] The system of differential equations is as follows:

[0080] ;

[0081] Where x is the initial concentration of the DOM excited state SENS*, and y is The concentrations are: m is the initial concentration of the substrate chemical TC; k0 is the SENS* self-decay rate constant; k1 is the bimolecular reaction rate constant between SENS* and the target organic compound; k2 is the conversion rate constant of the reduced product; z is the total absorbance; and a is... The absorption coefficient, b is The absorption coefficient.

[0082] The equation group consists of three expressions, the first of which is: The expression represents the trend of triplet excited state concentration. Triplet excited states undergo two types of consumption processes simultaneously: one is consumption through a bimolecular reaction between the triplet excited state and the target organic compound; the other is spontaneous decay of the triplet excited state itself. Both types of consumption cause the triplet excited state concentration to decrease over time; therefore, both terms on the right-hand side of the equation are negative. The second differential equation is: The formula is used to represent the trend of reduced product concentration. The reaction between the triplet excited state and the target organic compound will generate reduced products, leading to an increase in the concentration of reduced products. At the same time, the reduced products themselves will continue to be converted and consumed, resulting in a decrease in concentration. The change in the concentration of reduced products is equal to the amount generated minus the amount converted and consumed. The third relationship is: A relationship between the detection amount and the substance concentration is established. The total absorbance is obtained by multiplying the concentrations of the triplet excited state and the reduced state products by their corresponding absorption coefficients and then adding them together, which corresponds to the measured transient absorption signal. Each parameter in the formula has a clear physical meaning: x represents the triplet excited state concentration, y represents the reduced state product concentration, m represents the target organic compound concentration, k0 represents the self-decay rate constant of the triplet excited state, k1 represents the bimolecular reaction rate constant between the triplet excited state and the target organic compound, k2 represents the conversion rate constant of the reduced state product, z represents the total absorbance, and a and b are the absorption coefficients of the triplet excited state and the reduced state product, respectively. Taking a scenario with multiple gradient p-HBSA concentrations as an example, substituting the corresponding target organic compound concentration m into the differential equation system yields a kinetic equation specific to each concentration. Subsequent fitting and solving work is then carried out based on the measured absorbance data.

[0083] An apparent decay kinetic model was established based on the reaction relationship between the triple excited state and the target organic compound. Corresponding kinetic equations were constructed according to different target organic compound concentrations, specifically including the following steps:

[0084] If the concentration of the target organic compound corresponding to the transient absorption decay curve is higher than the triplet excited state concentration, the transient absorption signal decay process is described by the apparent kinetic model in pseudo-first-order reaction form. The correlation between the apparent decay rate constant K and the concentration of the target organic compound m is obtained, and the calculation formula is as follows:

[0085] ;

[0086] Where K is the apparent decay rate constant, m is the initial concentration of the substrate chemical TC, k0 is the SENS* self-decay rate constant, and k1 is the bimolecular reaction rate constant between SENS* and the target organic compound.

[0087] Based on the fundamental kinetic model, a simplified derivation of the system satisfying specific concentration conditions is performed, establishing a quantitative correlation between the apparent decay rate constant and the target organic concentration. When the target organic concentration corresponding to the transient absorption decay curve is higher than the triple excited state concentration within the system, a pseudo-first-order reaction form of the apparent kinetic model can be used to characterize the overall decay process of the transient absorption signal, deriving a linear relationship between the apparent decay rate constant K and the initial concentration m of the substrate chemical TC. In the formula, k0 represents the decay rate constant of SENS* itself, and k1 is the bimolecular reaction rate constant between SENS* and the target organic compound. In the original experimental scenario with multiple gradients of p-HBSA concentrations, the p-HBSA concentrations of each group were much greater than the concentration of the triplet excited state generated by the reaction, and all were suitable for pseudo-first-order application conditions. It is only necessary to measure the apparent decay rate constants corresponding to different substrate concentrations, and the two core kinetic parameters k0 and k1 can be solved by fitting this linear relationship.

[0088] Based on the kinetic equation, multiple transient absorption decay curves under different concentration conditions are jointly fitted to extract the apparent decay constant under different concentration conditions. Based on the correlation between the apparent decay constant and the concentration of the target organic compound, the self-decay rate constant of the triple excited state and its bimolecular reaction rate constant with the target organic compound are solved. The specific steps include:

[0089] Based on the correlation between the apparent decay rate constant K and the target organic matter concentration m, the transient absorption decay curves under different target organic matter concentrations are input into a single exponential model for fitting. The single exponential model is as follows:

[0090] ;

[0091] Where z(t) is the transient absorbance, A is the amplitude parameter, K is the apparent decay rate constant, and B is the baseline parameter. The apparent decay rate constant K values ​​under different concentration conditions are obtained by fitting the transient absorption decay curves of each group using the nonlinear least squares method.

[0092] Based on the kinetic equations, the transient absorption decay curves corresponding to multiple concentrations were jointly fitted. First, the apparent decay constant for each group was calculated. Then, the two core rate constants of the triple excited state were further solved. Firstly, based on the correspondence between the apparent decay rate constant K and the target organic concentration m, a single exponential model was used to fit the transient absorption decay curve corresponding to each target organic concentration. The expression of the single exponential model is as follows: The fitting process uses the nonlinear least squares method to calculate the K value corresponding to each target organic compound concentration. Taking multiple p-HBSA concentrations as an example, the decay curves corresponding to different concentrations are individually fitted using this single exponential model, outputting multiple sets of corresponding concentration and apparent decay rate constant data. The fitting results are as follows: Figure 5 As shown, these data can be used to solve for the self-decay rate constant of the triple excited state and the bimolecular reaction rate constant of the triple excited state and the target organic compound.

[0093] Based on the apparent decay constant K values ​​corresponding to different concentrations, a linear fit was performed with the target organic concentration m as the abscissa and the apparent decay rate constant K as the ordinate. The intercept of the linear fit corresponds to the self-decay rate constant k0 of the triple excited state, and the slope corresponds to the bimolecular reaction rate constant k1 between the triple excited state and the target organic. The reliability of the fitting results was evaluated based on the coefficient of determination, standard error, and confidence level.

[0094] Two core kinetic parameters were solved using multiple sets of paired data, and the reliability of the fitting results was verified. First, the apparent decay rate constant K corresponding to different target organic concentrations was compiled. A coordinate system was established for linear fitting, with the target organic concentration m set as the abscissa and the apparent decay rate constant K set as the ordinate. After linear fitting, the intercept of the fitted line was the triplet excited state self-decay rate constant k0, and the slope of the fitted line was the bimolecular reaction rate constant k1 between the triplet excited state and the target organic. Then, three statistical indicators—the coefficient of determination, standard error, and confidence score—were used to determine the reliability of the linear fitting. For example, the K obtained from fitting p-HBSA concentrations of 0 mM, 1 mM, 2 mM, 2.5 mM, 3 mM, and 3.72 mM was 0.757 μs. -1 1.000us -1 1.129us -1 1.211us -1 1.253us -1 1.337us -1 A linear fit is performed on the two, such as Figure 6 As shown, it can be seen that as the p-HBSA concentration gradually increases, the apparent decay rate constant K continuously increases, and there is a good linear relationship between K and the p-HBSA concentration, with a linear fitting correlation coefficient R. 2 The value is 0.969, the p-value is 0.000367, and the standard error is 0.0135. The slope is 0.151, the intercept is 0.806, and the corresponding extrapolated intrinsic decay rate k0 is 0.806 μs. -1 k1 is 0.151mM -1 / us, converted to SI units, gives k0 as 8.06 × 10⁻⁶. 5 s -1 k1 is 1.51 × 10 8 M -1 ·s -1 .

[0095] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for solving the apparent reaction kinetic parameters of the triple excited state DOM using LFP data, characterized in that, The method includes the following specific steps: Transient absorption data were collected during the reaction of target organic compounds with dissolved organic matter at different initial concentrations to obtain the relationship between absorbance and time. Determine the initial reaction time, marking the time when the absorbance reaches its maximum value as the initial reaction time, and generate an updated time series and corresponding absorbance data based on the initial reaction time. The updated absorbance data is identified and corrected to obtain the processed absorbance data. The processed absorbance data is processed to obtain the denoised transient absorption attenuation curve; An apparent decay kinetic model was established based on the reaction relationship between the triple excited state and the target organic matter, and corresponding kinetic equations were constructed according to different target organic matter concentrations. Based on the kinetic equation, multiple transient absorption decay curves under different concentration conditions are jointly fitted to extract the apparent decay constant under different concentration conditions. Based on the correlation between the apparent decay constant and the concentration of the target organic compound, the self-decay rate constant of the triple excited state and its bimolecular reaction rate constant with the target organic compound are solved.

2. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 1, characterized in that, The transient absorption data of the reaction between target organic compounds and dissolved organic matter at different initial concentrations were collected to obtain the relationship between absorbance and time. This process includes the following steps: An aqueous solution containing dissolved organic matter is mixed with a target organic compound of known concentration. The dissolved organic matter system is instantaneously excited by a pulsed laser, and the change in absorbance over time is obtained by extracting the change in absorbance based on a transient absorption detector.

3. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 2, characterized in that, Determine the initial reaction time, marking the moment when absorbance reaches its maximum value as the initial reaction time. Generate an updated time series and corresponding absorbance data based on the initial reaction time, specifically including the following steps: The moment corresponding to the maximum absorbance value in the relationship between absorbance and time is extracted as the initial reaction time t0. Based on the initial reaction time t0, the updated time series and corresponding absorbance data are obtained.

4. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 3, characterized in that, The updated absorbance data is identified and corrected to obtain the processed absorbance data, specifically including the following steps: Based on the updated absorbance data, the absorbance difference between multiple consecutive measurement intervals is determined, and areas with absorbance differences less than a preset threshold are marked as abnormal areas. The start time t1 and end time t2 of the abnormal region are collected. Using the total time corresponding to several measurement intervals as Δt, the maximum absorbance A is extracted within (t1-Δt, t1). max1 and the corresponding time t max1 Extract the maximum absorbance A within (t2, t2+Δt). max2 and the corresponding time t max2 Delete t max1 To t max2 All measurements between; Based on (t) max1 A max1 ) and (t max2 A max2 A linear equation is constructed to represent time and absorbance. The absorbance of the deleted region is then filled in according to the measurement interval to obtain the processed absorbance data.

5. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 4, characterized in that, The processed absorbance data is then processed to obtain the denoised transient absorption attenuation curve, specifically including the following steps: The processed absorbance data is smoothed using the Savitzky-Golay filter, and the transient absorption attenuation curve after denoising is obtained by setting the filter window length and polynomial order based on the data sampling interval.

6. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 5, characterized in that, A set of differential equations is constructed based on the spontaneous decay reaction of the triple excited state, the reaction of the triple excited state with the target organic compound to generate the reduced product, and the subsequent transformation reaction of the reduced product. ； in, Absorbance For compounds concentration, For compounds concentration, and Compounds and The corresponding absorption coefficient.

7. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 6, characterized in that, The system of differential equations is as follows: ； Where x is the instantaneous concentration of SENS* in the excited state of DOM, and y is The concentrations are: m is the instantaneous concentration of the substrate chemical TC, k0 is the SENS* self-decay rate constant, k1 is the bimolecular reaction rate constant between SENS* and the target organic compound, k2 is the reduced product conversion rate constant, z is the total absorbance, and a is... The absorption coefficient, b is The absorption coefficient.

8. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 7, characterized in that, An apparent decay kinetic model was established based on the reaction relationship between the triple excited state and the target organic compound. Corresponding kinetic equations were constructed according to different target organic compound concentrations, specifically including the following steps: If the concentration of the target organic compound corresponding to the transient absorption decay curve is higher than the triplet excited state concentration, the transient absorption signal decay process is described by the apparent kinetic model in pseudo-first-order reaction form. The correlation between the apparent decay rate constant K and the concentration of the target organic compound m is obtained, and the calculation formula is as follows: ； Where K is the apparent decay rate constant, m is the initial concentration of the substrate chemical TC, k0 is the SENS* self-decay rate constant, and k1 is the bimolecular reaction rate constant between SENS* and the target organic compound.

9. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 8, characterized in that, Based on the kinetic equation, multiple transient absorption decay curves under different concentration conditions are jointly fitted to extract the apparent decay constant under different concentration conditions. Based on the correlation between the apparent decay constant and the concentration of the target organic compound, the self-decay rate constant of the triple excited state and its bimolecular reaction rate constant with the target organic compound are solved. The specific steps include: Based on the correlation between the apparent decay rate constant K and the target organic matter concentration m, the transient absorption decay curves under different target organic matter concentrations are input into a single exponential model for fitting. The single exponential model is as follows: ； Where z(t) is the transient absorbance, A is the amplitude parameter, K is the apparent decay rate constant, and B is the baseline parameter. The apparent decay rate constant K values ​​under different concentration conditions are obtained by fitting the transient absorption decay curves of each group using the nonlinear least squares method.

10. The method for solving the apparent reaction kinetic parameters of the triple excited state DOM from LFP data according to claim 9, characterized in that, Based on the apparent decay constant K values ​​corresponding to different concentrations, a linear fit was performed with the target organic concentration m as the abscissa and the apparent decay rate constant K as the ordinate. The intercept of the linear fit corresponds to the self-decay rate constant k0 of the triple excited state, and the slope corresponds to the bimolecular reaction rate constant k1 between the triple excited state and the target organic. The reliability of the fitting results was evaluated based on the coefficient of determination, standard error, and confidence level.

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