Dynamic monitoring method for pH value of expiratory condensate

Abstract

The invention relates to the technical field of spectrum analysis of expiratory condensate, in particular to a dynamic monitoring method for the pH value of expiratory condensate. The method comprises the following steps: firstly, acquiring ultraviolet visible spectrums of a current sample and a historical sample of expiration condensate; further obtaining a respiration similarity coefficient according to the consistency of the current protein peak intensity and the historical protein peak intensity; further obtaining a reference coefficient according to the consistency of the intensity difference between the current and historical nucleic acid absorption peaks and the intensity difference between the protein peaks; further in nitrate and bilirubin, according to the intensity difference of absorption peaks of each target component of the current sample and the same component in all historical samples, two interference coefficients of the current sample are obtained in combination with a respiration similarity coefficient and a reference coefficient; finally, according to the difference between the two interference coefficients, the absorbance ratio of phenol red is corrected, the pH value is obtained, interference caused by breathing state fluctuation can be effectively eliminated, and the accuracy and stability of expiration condensate pH monitoring are improved.

Description

Technical Field

[0001] This invention relates to the field of spectral analysis technology for exhaled condensate, and specifically to a method for dynamic monitoring of the pH value of exhaled condensate. Background Technology

[0002] Exhaled condensate is the liquid formed by the condensation of water vapor in the air exhaled by the human body during the cooling process. It typically contains various substances from the respiratory tract, such as water, electrolytes, and metabolic products. Ultraviolet-visible spectroscopy can monitor pH changes in real time and non-invasively without direct contact with the sample, avoiding the risk of sample contamination. Furthermore, it can detect small-scale pH changes that are difficult to detect using traditional methods, thus improving the reliability of the detection.

[0003] However, exhaled condensate can be affected by various factors such as respiratory status, respiratory rate, and expiratory volume. For example, the respiratory function of some patients with chronic diseases may be restricted, leading to unstable exhalation or insufficient expiratory volume, which in turn affects the collection of condensate. The quality and quantity of exhaled condensate may fluctuate, thus affecting the stability and representativeness of the sample. In the case of unstable exhaled condensate collection, the measured pH value may not accurately reflect the patient's actual acid-base status, affecting the accuracy of the monitoring results. Summary of the Invention

[0004] To address the technical problem that a patient's respiratory status affects the pH monitoring accuracy of exhaled breath condensate samples, the present invention aims to provide a method for dynamic monitoring of exhaled breath condensate pH. The specific technical solution adopted is as follows: A method for dynamically monitoring the pH value of exhaled condensate, the method comprising: Obtain the UV-Vis spectra of current and historical breath condensate samples; Based on the consistency of protein peak intensities, the respiratory similarity coefficient of the current sample compared to each historical sample is obtained; based on the consistency of the intensity differences of nucleic acid absorption peaks and protein peak intensities, the reference coefficient of each historical sample relative to the current sample is obtained; taking either nitrate or bilirubin as the target component, based on the intensity differences of the absorption peaks of each target component in the current sample and the same component in all historical samples, combined with the respiratory similarity coefficient and the reference coefficient, the interference coefficient of the two target components in the current sample is obtained; Based on the difference in the interference coefficients of the two target components, the absorbance ratio of phenol red was corrected and the pH value was obtained.

[0005] Furthermore, the method for obtaining the respiratory similarity coefficient includes: Based on the consistency of the absorbance of the current sample with that of each historical sample at a wavelength of 280 nm, the respiratory similarity coefficient of the current sample compared with each historical sample is obtained.

[0006] Furthermore, the method for obtaining the reference coefficient includes: Obtain the ratio of the absorbance of the current sample to that of each historical sample at a wavelength of 280 nm and the ratio of the absorbance at a wavelength of 260 nm. Based on the consistency of the two ratios, obtain the reference coefficient of each historical sample relative to the current sample.

[0007] Furthermore, the method for obtaining the interference coefficient includes: Based on the intensity difference of the absorption peak of the target component, and combined with the respiration similarity coefficient, the measurement interference coefficient of the target component of the current sample compared with each historical sample is obtained. Based on the reference coefficient, the interference coefficients of the target component and the measurement interference coefficients corresponding to all historical samples are fused to obtain the interference coefficients of the two target components of the current sample.

[0008] Furthermore, the method for obtaining the interference coefficient includes: The negative correlation mapping of the respiratory similarity coefficient is used as an interference factor; the ratio difference of absorbance of the target component of the current sample compared with each historical sample and the corresponding interference factor are fused to obtain the measurement interference coefficient of the target component of the current sample compared with each historical sample.

[0009] Further, the method for obtaining the interference coefficients of the two target components in the current sample by fusing the target component with the measurement interference coefficients corresponding to all historical samples based on the reference coefficient includes: The weighting factor is the proportion of the reference coefficient corresponding to the historical sample to the sum of the reference coefficients of all historical samples. The interference coefficients of each target component and all historical samples are weighted and summed using the weighted weights, and the weighted sum is used as the interference coefficients of the two target components.

[0010] Furthermore, the method for correcting the absorbance ratio of phenol red includes: Based on the ratio of the interference coefficients of nitrate to bilirubin, the ratio of the absorbance of the basic peak to the absorbance of the acidic peak is corrected, and the corrected absorbance ratio of phenol red is obtained.

[0011] Furthermore, the method for obtaining the corrected absorbance ratio includes: The ratio of the interference coefficient of nitrate to that of bilirubin was used as a correction coefficient. The ratio of absorbance at 560 nm to that at 433 nm was used as the alkaline-acid ratio. The product of the alkaline-acid ratio and the correction coefficient was used as the corrected absorbance ratio.

[0012] Furthermore, the method for obtaining the pH value includes: The ratio of the absorbance of the alkaline peak to the acidic peak of the phenol red solution at different pH values ​​was determined in advance, and a curve showing the relationship between the absorbance ratio of phenol red and pH value was constructed. Based on the corrected absorbance ratio of the current sample, the corresponding pH value in the curve was obtained.

[0013] Furthermore, the method for obtaining the relationship curve includes: The pH range was pre-determined to be 4.20-8.80 with a step size of 0.20, and the relationship curve was fitted using a four-parameter logistic function.

[0014] The present invention has the following beneficial effects: This invention first obtains the UV-Vis spectra of current and historical breath condensate samples to provide an analytical basis. Further, based on the consistency of protein peak intensities between the current and historical samples, a respiratory similarity coefficient is obtained to characterize the similarity of respiratory conditions between the current sample and each historical sample, providing a basis for subsequent fusion of spectral differences in the same components between the current sample and all historical samples. Furthermore, utilizing the fact that nucleic acid absorption peaks differ from protein absorption peaks in the UV spectrum, providing information independent of protein peaks, a reference coefficient is obtained based on the consistency of the intensity differences between the current and historical nucleic acid absorption peaks and protein peaks, characterizing the reference value of historical samples for the current sample and avoiding... The impact of protein errors on the results provides further evidence for subsequent analysis. Furthermore, in nitrates and bilirubin, based on the intensity difference of the absorption peaks of each target component in the current sample and the same component in all historical samples, combined with the respiratory similarity coefficient and reference coefficient, two interference coefficients are obtained for the current sample. This provides a basis for accurately assessing whether changes in acidity and alkalinity are caused by changes in respiratory conditions, thereby correcting the interference of respiratory conditions on pH. Finally, based on the difference between the two interference coefficients, the absorbance ratio of phenol red is corrected to obtain the pH value. This effectively eliminates the bias interference of acidic or alkaline components caused by changes in respiratory state, improving the reliability and representativeness of pH monitoring results. This invention analyzes protein and nucleic acid peaks to determine the respiratory similarity coefficient and reference coefficient, calculates the interference coefficients of nitrates and bilirubin, and corrects the absorbance ratio of phenol red to obtain the pH value. This effectively eliminates the interference caused by fluctuations in respiratory state, improving the accuracy and stability of exhaled condensate pH monitoring. Attached Figure Description

[0015] To more clearly illustrate the technical solutions and advantages 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.

[0016] Figure 1 A flowchart illustrating a method for dynamically monitoring the pH value of exhaled condensate according to an embodiment of the present invention; Figure 2 An example diagram of the ultraviolet-visible absorption spectrum of exhaled condensate provided in an embodiment of the present invention; Figure 3 This is a flowchart illustrating a method for obtaining interference coefficients according to an embodiment of the present invention. Detailed Implementation

[0017] 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 a method for dynamic monitoring of exhaled condensate pH value 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.

[0018] 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.

[0019] The following description, in conjunction with the accompanying drawings, details a specific scheme for a dynamic monitoring method for the pH value of exhaled condensate provided by the present invention.

[0020] Please see Figure 1 The diagram illustrates a flowchart of a method for dynamically monitoring the pH value of exhaled condensate according to an embodiment of the present invention, specifically including: Step S1: Obtain the UV-Vis spectra of the current and historical breath condensate samples.

[0021] In one embodiment of the invention, for the patient currently being monitored, they are connected to a breath condensate collection device at regular intervals. The patient exhales through a breathing tube or mask, and the exhaled gas passes through a condensation system. Under the action of the cooling device, the water vapor in the gas is effectively cooled and condensed into liquid, flowing into a pre-prepared collection bottle or small container.

[0022] Then, appropriate stabilization measures (such as refrigeration or the addition of stabilizers) are taken to prevent changes in sample composition before storage or analysis. The processed samples are then scanned using a UV-Vis spectrometer. These data record the spectral characteristics of each sample and are stored chronologically for subsequent analysis and comparison.

[0023] In one embodiment of the invention, two data records from 30 individuals with healthy respiratory systems during calm breathing, totaling 60 historical samples, can be pre-acquired and provided for comparative analysis of the current sample. Additionally, the exhaled condensate of the currently monitored patient can be obtained to provide a basis for analysis. In other embodiments of the invention, the implementer can set the number and range of other historical samples to be selected.

[0024] Please see Figure 2 It shows an example diagram of the ultraviolet-visible absorption spectrum of exhaled condensate provided in an embodiment of the present invention. Figure 2 The horizontal axis represents wavelength in nanometers (nm), and the vertical axis represents absorbance in au.

[0025] It should be noted that this solution mainly analyzes respiratory condensate. The sampling frequency or sampling scheme of exhaled condensate can be adjusted by the implementer, as it is a well-known technology and will not be limited here.

[0026] Step S2: Based on the consistency of protein peak intensity, obtain the respiratory similarity coefficient of the current sample compared to each historical sample; based on the consistency of the intensity difference of nucleic acid absorption peak and the intensity difference of protein peak, obtain the reference coefficient of each historical sample relative to the current sample; taking either nitrate or bilirubin as the target component, based on the intensity difference of the absorption peak of each target component in the current sample and the same component in all historical samples, combined with the respiratory similarity coefficient and the reference coefficient, obtain the interference coefficient of the two target components in the current sample.

[0027] Since respiratory conditions such as respiratory rate and expiratory volume directly affect the composition and metabolic state of a sample, they may alter the protein concentration or distribution in the sample, resulting in fluctuations in protein peak intensity. Therefore, based on the consistency of protein peak intensity, the similarity of respiratory conditions corresponding to different samples can be analyzed, and the respiratory similarity coefficient of the current sample compared to each historical sample can be obtained. This coefficient characterizes the degree of similarity between the respiratory conditions of the current sample and each historical sample, providing a basis for subsequent fusion of the spectral differences of the current sample and all historical samples in the same component.

[0028] Preferably, in one embodiment of the present invention, the consistency of protein peak intensity is reflected by comparing the absorbance of the ultraviolet-visible spectra of different samples at a wavelength of 280 nm, and the respiratory similarity coefficient of the current sample compared with each historical sample is obtained based on the consistency of the absorbance of the current sample with each historical sample at a wavelength of 280 nm.

[0029] As an example, the absolute value of the difference between the absorbance of the current sample and each historical sample at a wavelength of 280nm is used as the independent variable. After negative correlation mapping using the exp(-x) function with the natural constant e as the base, the mapped value is used as the respiratory similarity coefficient between the current sample and each historical sample.

[0030] Here, x is the independent variable, and the difference in absorbance is represented by the absolute value of the difference. The logic is then adjusted by a negative correlation mapping function.

[0031] In other embodiments of the present invention, the implementer may also use the reciprocal or other negative correlation mapping functions to adjust the absolute value of the difference in absorbance at a wavelength of 280nm. For example, the sum of the absolute value of the difference in absorbance at a wavelength of 280nm and a preset positive parameter divided by zero is taken as the reciprocal and normalized, and then used as the respiratory similarity coefficient. The preset positive parameter divided by zero can be 0.01 to prevent the denominator from being zero. The normalization can be linear normalization, which is performed on the data dimension composed of all recorded feature parameters to be normalized. For example, here it is the reciprocal of the sum of the absolute value of the difference in absorbance at a wavelength of 280nm and the preset positive parameter divided by zero.

[0032] Saliva and nasopharyngeal secretions may contain high concentrations of amylase and other components, which can cause an increase in protein peak intensity in the ultraviolet spectrum, thus interfering with the accurate assessment of protein concentration. To eliminate this interference, it is necessary to simultaneously examine changes in the absorbance of nucleic acid peaks to determine the consistent usability of the current exhaled breath condensate sample compared to each sample in the historical dynamic monitoring process.

[0033] Nucleic acids (such as DNA and RNA) exhibit absorption peaks in ultraviolet spectra that differ from those of proteins, thus providing information independent of protein peaks. Therefore, by analyzing the consistency between the intensity differences of nucleic acid absorption peaks and those of protein peaks, a reference coefficient for each historical sample can be obtained relative to the current sample. This characterizes the reference value of historical samples for the current sample and avoids the influence of protein errors on the results.

[0034] Preferably, in one embodiment of the present invention, considering that the absorption peak of nucleic acid in the ultraviolet spectrum is mainly concentrated at 260 nm, when the ratio of absorbance of two samples at 280 nm and 260 nm is more similar, it indicates that the composition structure of the current sample is consistent with that of the historical sample, that is, the breathing conditions and sample stability are more similar, and the historical sample has higher reference value for the current sample. Based on this, the ratio of the absorbance of the current sample to that of each historical sample at a wavelength of 280 nm and the ratio of the absorbance at a wavelength of 260 nm are obtained. Based on the consistency of the two ratios, the reference coefficient of each historical sample to the current sample is obtained.

[0035] As an example, for each historical sample, the ratio of the absorbance of the current sample at 280nm wavelength to the absorbance of historical samples at 280nm wavelength is used as the first ratio value; the ratio of the absorbance of the current sample at 260nm wavelength to the absorbance of historical samples at 260nm wavelength is used as the second ratio value; the absolute value of the difference between the first ratio value and the second ratio value is used as the independent variable, and after negative correlation mapping by the exp(-x) function with the natural constant e as the base, the mapped value is used as the reference coefficient between the current sample and the corresponding historical sample.

[0036] The first and second ratio values ​​respectively represent the intensity differences of nucleic acid absorption peaks and protein peaks. After mapping the absolute values ​​of the differences with negative correlation, the consistency of the intensity differences is shown.

[0037] In other embodiments of the present invention, the implementer may also use the reciprocal method to adjust the absolute value of the difference between the first proportional value and the second proportional value, which is consistent with the method of adjusting the absolute value of the difference in absorbance at a wavelength of 280nm, and will not be described again.

[0038] Considering changes in respiratory conditions, such as a decrease in respiratory rate potentially leading to excessive carbon dioxide accumulation and consequently a change in the acidic environment, nitrate levels may rise at low pH. ), may be restored to The absorption peak shifts, and pH may indirectly interfere by affecting other coexisting organic compounds. This can lead to differences in the intensity of absorption peaks among different samples; for example, an increase in respiratory rate may lead to hyperventilation of carbon dioxide, which in turn causes changes in the alkaline environment, affecting the concentration and absorbance of bilirubin. Furthermore, certain respiratory pathological factors may also cause similar acidic or alkaline changes. Therefore, it is crucial to accurately assess whether acidic and alkaline changes are caused by changes in respiratory conditions, thereby correcting the interference of respiratory conditions on pH. The respiratory similarity coefficient characterizes the degree of similarity of respiratory conditions and reflects the credibility of the difference in absorption peaks of the same components being caused by different respiratory conditions, while the reference coefficient reflects the reference value of historical samples for the current sample. Therefore, by taking either nitrate or bilirubin as the target component, and based on the intensity difference of the absorption peaks of each target component in the current sample and the same component in all historical samples, combined with the respiratory similarity coefficient and the reference coefficient, the interference coefficient of the two target components in the current sample is obtained.

[0039] Preferably, in one embodiment of the present invention, please refer to Figure 3 The diagram illustrates a flowchart of a method for obtaining interference coefficients according to an embodiment of the present invention, specifically including: Step S201: Based on the intensity difference of the absorption peak of the target component, and combined with the respiration similarity coefficient, obtain the measurement interference coefficient of the target component of the current sample compared with each historical sample.

[0040] Considering that the smaller the respiratory similarity coefficient, the greater the difference in respiratory conditions between the current sample and historical samples, the greater the difference in the intensity of the absorption peak of the target component is likely caused by different respiratory states, indicating that the current respiration has a stronger interference with pH measurement. Based on this, the negative correlation mapping of the respiratory similarity coefficient is used as an interference factor; by fusing the proportional difference in absorbance of the target component of the current sample compared with each historical sample and the corresponding interference factor, the measurement interference coefficient of the target component of the current sample compared with each historical sample is obtained.

[0041] As an example, nitrate corresponds to a wavelength of 200 nm, and bilirubin corresponds to a wavelength of 450 nm. The absolute value of the difference between the absorbance of the target component at the wavelength corresponding to the current sample and the absorbance of the target component at the wavelength corresponding to the historical sample is used as the numerator, and the absorbance of the target component at the wavelength corresponding to the current sample is used as the denominator. The ratio of the fraction is used as the difference factor between the current sample and the corresponding historical sample in terms of the target component, showing the difference in the intensity of the absorption peak of the same component. The respiratory similarity coefficient is negatively correlated using the exp(-x) function and used as the interference factor; the product of the difference factor and the interference factor between the current sample and each historical sample on the target component is used as the measurement interference coefficient between the current sample and each historical sample on the target component.

[0042] It should be noted that in other embodiments of the present invention, considering that the absorption peak of bilirubin shifts to 415-420 nm under acidic conditions, 415 nm can be used to replace nitrate as an acidity indicator.

[0043] Step S202: Based on the reference coefficient, fuse the target component with the measurement interference coefficients corresponding to all historical samples to obtain the interference coefficients of the two target components of the current sample.

[0044] Considering that there are multiple historical samples for the determination interference coefficient of the target component, and that different historical samples have different reference values, the larger the proportion of the reference coefficient to the sum of the reference coefficients of all historical samples, the higher the reference value of the corresponding determination interference coefficient. Therefore, the determination interference coefficients of the target component and all historical samples are fused based on the reference coefficient.

[0045] As an example, the weighting is based on the proportion of the reference coefficient corresponding to the historical sample to the sum of the reference coefficients of all historical samples. The measurement interference coefficients of each target component and all historical samples are weighted and summed, and the weighted sum is used as the interference coefficients of the two target components.

[0046] Step S3: Based on the difference in the interference coefficients of the two target components, correct the absorbance ratio of phenol red and obtain the pH value.

[0047] In the UV-Vis spectrum of exhaled breath condensate, the absorbance of phenol red is closely related to its acidity or alkalinity. When breathing conditions change, leading to insufficient representativeness of the sample, interference from acidic or alkaline measurements may be introduced. To correct for breathing interference, the absorbance ratio of phenol red needs to be adjusted based on the difference in interference coefficients between the two target components to obtain a more accurate pH value.

[0048] Preferably, in one embodiment of the present invention, considering that the ratio of the interference coefficients of nitrate to bilirubin represents the relative degree of interference of changes in respiratory conditions on acidic and alkaline components, reflecting the difference in the interference coefficients of the two target components, and that the ratio of the absorbance of the alkaline peak to the acidic peak represents the actual response of phenol red under different acidic and alkaline conditions, i.e., the original acid-base balance level of the system, the ratio of the absorbance of the alkaline peak to the acidic peak is corrected according to the ratio of the interference coefficients of nitrate to bilirubin to obtain the corrected absorbance ratio of phenol red.

[0049] As an example, phenol red has an absorption peak at 560 nm under alkaline conditions and an absorption peak at 433 nm under acidic conditions. The ratio of the interference coefficient of nitrate to that of bilirubin is used as a correction coefficient. The ratio of the absorbance at 560 nm to that at 433 nm is used as the alkaline-acid ratio. The product of the alkaline-acid ratio and the correction coefficient is used as the corrected absorbance ratio.

[0050] By correcting the absorbance ratio of the alkaline peak to the acidic peak, the deviation interference of acidic or alkaline components caused by changes in respiratory state (such as respiratory rate, expiratory volume, etc.) can be effectively eliminated, so that the phenol red absorbance ratio can more accurately reflect the true acid-base state of the exhaled condensate, thereby improving the reliability and representativeness of pH monitoring results.

[0051] The corrected absorbance ratio provides a reliable basis for obtaining the pH value, so the pH value is further obtained.

[0052] In one embodiment of the present invention, the ratio of the absorbance of the alkaline peak to the acidic peak of the phenol red solution at different pH values ​​is determined in advance, and a relationship curve between the absorbance ratio of phenol red and the pH value is constructed; the corresponding pH value in the relationship curve is obtained based on the corrected absorbance ratio of the current sample.

[0053] As an example, according to known technology, the pH value of human exhaled condensate usually fluctuates between 4.5 and 8.0, with most samples concentrated in the range of 5.5 to 7.5. Therefore, the pre-determined pH range is 4.20-8.80 with a step size of 0.20, and a four-parameter logistic function is used to fit the relationship curve.

[0054] It should be noted that in other embodiments of the present invention, the implementer may adjust the step size of the pre-determined pH range and use algorithms such as least squares to fit the relationship curve. Both of these and the four-parameter logistic function are existing technologies and will not be described in detail here.

[0055] In summary, to address the technical problem of how a patient's respiratory state affects the pH monitoring accuracy of exhaled condensate samples, this invention provides a dynamic pH monitoring method for exhaled condensate. This invention first obtains the UV-Vis spectra of the current and historical exhaled condensate samples; then, based on the consistency of protein peak intensities between the current and historical samples, a respiratory similarity coefficient is obtained; further, based on the consistency of the intensity differences between the current and historical nucleic acid absorption peaks and the protein peak intensities, a reference coefficient is obtained; further, for nitrates and bilirubin, based on the intensity differences of the absorption peaks of each target component in the current sample and the same component in all historical samples, combined with the respiratory similarity coefficient and the reference coefficient, two interference coefficients for the current sample are obtained; finally, based on the difference between the two interference coefficients, the absorbance ratio of phenol red is corrected, and the pH value is obtained. This method analyzes protein and nucleic acid peaks, uses respiratory similarity coefficients and reference coefficients, calculates the interference coefficients of nitrates and bilirubin, and corrects the absorbance ratio of phenol red to obtain the pH value, effectively eliminating interference caused by fluctuations in respiratory state and improving the accuracy and stability of exhaled condensate pH monitoring.

[0056] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0057] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for dynamically monitoring the pH value of exhaled condensate, characterized in that, The method includes: Obtain the UV-Vis spectra of current and historical breath condensate samples; Based on the consistency of protein peak intensities, the respiratory similarity coefficient of the current sample compared to each historical sample is obtained; based on the consistency of the intensity differences of nucleic acid absorption peaks and protein peak intensities, the reference coefficient of each historical sample relative to the current sample is obtained; taking either nitrate or bilirubin as the target component, based on the intensity differences of the absorption peaks of each target component in the current sample and the same component in all historical samples, combined with the respiratory similarity coefficient and the reference coefficient, the interference coefficient of the two target components in the current sample is obtained; Based on the difference in the interference coefficients of the two target components, the absorbance ratio of phenol red was corrected and the pH value was obtained.

2. The method for dynamically monitoring the pH value of exhaled condensate according to claim 1, characterized in that, The method for obtaining the respiratory similarity coefficient includes: Based on the consistency of the absorbance of the current sample with that of each historical sample at a wavelength of 280 nm, the respiratory similarity coefficient of the current sample compared with each historical sample is obtained.

3. The method for dynamically monitoring the pH value of exhaled condensate according to claim 1, characterized in that, The method for obtaining the reference coefficient includes: Obtain the ratio of the absorbance of the current sample to that of each historical sample at a wavelength of 280 nm and the ratio of the absorbance at a wavelength of 260 nm. Based on the consistency of the two ratios, obtain the reference coefficient of each historical sample relative to the current sample.

4. The method for dynamically monitoring the pH value of exhaled condensate according to claim 1, characterized in that, The method for obtaining the interference coefficient includes: Based on the intensity difference of the absorption peak of the target component, and combined with the respiration similarity coefficient, the measurement interference coefficient of the target component of the current sample compared with each historical sample is obtained. Based on the reference coefficient, the interference coefficients of the target component and the measurement interference coefficients corresponding to all historical samples are fused to obtain the interference coefficients of the two target components of the current sample.

5. The method for dynamic monitoring of pH value of exhaled condensate according to claim 4, characterized in that, The method for obtaining the interference coefficient includes: The negative correlation mapping of the respiratory similarity coefficient is used as an interference factor; the ratio difference of absorbance of the target component of the current sample compared with each historical sample and the corresponding interference factor are fused to obtain the measurement interference coefficient of the target component of the current sample compared with each historical sample.

6. The method for dynamically monitoring the pH value of exhaled condensate according to claim 4, characterized in that, The method for obtaining the interference coefficients of the two target components in the current sample by fusing the target component with the measurement interference coefficients corresponding to all historical samples based on the reference coefficient includes: The weighting factor is the proportion of the reference coefficient corresponding to the historical sample to the sum of the reference coefficients of all historical samples. The interference coefficients of each target component and all historical samples are weighted and summed using the weighted weights, and the weighted sum is used as the interference coefficients of the two target components.

7. The method for dynamically monitoring the pH value of exhaled condensate according to claim 1, characterized in that, The method for correcting the absorbance ratio of phenol red includes: Based on the ratio of the interference coefficients of nitrate to bilirubin, the ratio of the absorbance of the basic peak to the absorbance of the acidic peak is corrected, and the corrected absorbance ratio of phenol red is obtained.

8. The method for dynamically monitoring the pH value of exhaled condensate according to claim 7, characterized in that, The method for obtaining the corrected absorbance ratio includes: The ratio of the interference coefficient of nitrate to that of bilirubin was used as a correction coefficient. The ratio of absorbance at 560 nm to that at 433 nm was used as the alkaline-acid ratio. The product of the alkaline-acid ratio and the correction coefficient was used as the corrected absorbance ratio.

9. The method for dynamically monitoring the pH value of exhaled condensate according to claim 7, characterized in that, The method for obtaining the pH value includes: The ratio of the absorbance of the alkaline peak to the acidic peak of the phenol red solution at different pH values ​​was determined in advance, and a curve showing the relationship between the absorbance ratio of phenol red and pH value was constructed. Based on the corrected absorbance ratio of the current sample, the corresponding pH value in the curve was obtained.

10. A method for dynamically monitoring the pH value of exhaled condensate according to claim 9, characterized in that, The method for obtaining the relationship curve includes: The pH range was pre-determined to be 4.20-8.80 with a step size of 0.20, and the relationship curve was fitted using a four-parameter logistic function.

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