Method and system for detecting oxidation potential of atmospheric particulates

Abstract

The invention relates to the technical field of chemical detection, in particular to an atmospheric particulate oxidation potential detection method and system.The detection method comprises the steps that reaction liquid obtained by mixed incubation of a probe molecule solution and an atmospheric particulate solution is injected into a photoelectrochemical micro-fluidic chip of a three-electrode system; and substituting the obtained photocurrent response value into a pre-established standard curve to obtain an equivalent value of the oxidizing component in the reaction liquid, thereby realizing the detection of the oxidation potential of the atmospheric particulates. A photoelectrochemical micro-fluidic chip is formed by combining a photoelectrochemical sensor and a micro-fluidic system, and an efficient analysis system is constructed. According to the present invention, the specific reaction between the oxidizing component in the atmospheric particulate matter and the probe molecule is adopted to cause the consumption of the probe molecule or the generation of the reactant so as to cause the quantitative change of the photocurrent signal, such that the atmospheric particulate matter oxidation potential is indirectly represented by detecting the consumption of the probe molecule; the interference of a complex matrix on direct detection is effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of chemical detection technology, and in particular to a method and system for detecting the oxidation potential of atmospheric particulate matter. Background Technology

[0002] Particulate matter (PM), as a complex mixture, exhibits dynamic variations in size and chemical composition across regions, seasons, and emission sources, leading to significant differences in its toxic effects. Epidemiological studies have confirmed a close association between PM exposure and respiratory / cardiovascular diseases, with the core pathogenic mechanism being the induction of oxidative stress: after penetrating the alveolar barrier, components such as polycyclic aromatic hydrocarbons and heavy metals carried by particulate matter catalyze the production of reactive oxygen species (ROS), disrupting the intracellular oxidation-antioxidant balance and triggering inflammation and deoxyribonucleic acid (DNA) damage. Assessing the toxic effects of particulate matter is a crucial step in measuring population health risks. However, traditional assessment methods based on mass concentration have a fundamental limitation—they cannot distinguish the heterogeneity of toxicity among different components, resulting in frequent contradictions in health effect research results. Oxidative potential (OP) has emerged as a novel exposure indicator. It directly characterizes the ability of PM to induce oxidative stress, integrates chemical composition, surface reactivity, and multi-component synergistic effects, and has a significantly better correlation with health endpoints than mass concentration. It is gradually becoming a core parameter for toxicity assessment.

[0003] Existing oxidative potential (OP) detection technologies are mainly divided into two categories: bioanalytical methods and chemical instrumental methods. The oxidative potential of atmospheric particulate matter is a key indicator for assessing its health risks. However, traditional detection methods, such as ultraviolet spectrophotometry and high-performance liquid chromatography, have limitations such as complex operation procedures, long analysis cycles, high equipment costs, and susceptibility to sample matrix interference, making it difficult to meet the needs of rapid on-site detection and large-scale sample screening.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method and system for detecting the oxidation potential of atmospheric particulate matter, which aims to solve the problems of complex operation and insufficient sensitivity of existing detection methods.

[0006] The technical solution of the present invention is as follows: A method for detecting the oxidation potential of atmospheric particulate matter, comprising the following steps: The probe molecule solution was mixed with an atmospheric particulate matter solution, and after incubation, a reaction solution was obtained. The reaction solution was injected into a photoelectrochemical microfluidic chip with a three-electrode system to obtain a photocurrent response value; wherein, the working electrode in the three-electrode system was modified with a thin film of photoactive material; By substituting the photocurrent response value into a pre-established standard curve, the equivalent value of the oxidizing component in the reaction solution is obtained, thereby realizing the detection of the oxidation potential of atmospheric particulate matter.

[0007] The method for detecting the oxidation potential of atmospheric particulate matter, wherein the probe molecules in the probe molecule solution are selected from one or more of electron donor probes, electron acceptor probes, and enzyme catalytic reaction probes.

[0008] The method for detecting the oxidation potential of atmospheric particulate matter, wherein the probe molecule is selected from one or more of the following: dithiothreitol, glutathione, cysteine, ascorbic acid, dopamine, potassium ferrocyanide / potassium ferrocyanide, methylene blue, horseradish peroxidase-hydrogen peroxide (HRP-H2O2) system, superoxide dismutase (SOD), and catalase (CAT).

[0009] The method for detecting the oxidation potential of atmospheric particulate matter, wherein the concentration of the probe molecule solution is 1 mM-3 mM; and the volume ratio of the probe molecule solution to the atmospheric particulate matter solution is (4-8):1.

[0010] The method for detecting the oxidation potential of atmospheric particulate matter, wherein the incubation temperature is 20℃-40℃ and the incubation time is 10min-60min.

[0011] The method for detecting the oxidation potential of atmospheric particulate matter, wherein the material of the photoelectric active material film is selected from one or more of CdIn2S4-MoS2 heterojunction, TiO2, ZnO, BiVO4, CdS, In2S3, CuInS2, g-C3N4, CsPbBr3, and BP.

[0012] The method for detecting the oxidation potential of atmospheric particulate matter, wherein the method for establishing the pre-established standard curve includes the following steps: A series of reaction solutions were obtained by mixing quantitative probe molecule solutions with standard oxidant solutions of gradient concentrations and then incubating them. The series of reaction solutions were injected into a photoelectrochemical microfluidic chip with a three-electrode system to obtain a series of photocurrent response values; A linear relationship was established between standard oxidant solutions of gradient concentrations and a series of photocurrent response values, which served as a standard curve.

[0013] A detection system for the oxidation potential of atmospheric particulate matter used to implement the detection method, comprising: A photoelectrochemical microfluidic chip includes a polymer substrate with microfluidic channels formed on its surface, and a transparent conductive substrate disposed on the polymer substrate and located on one side of the microfluidic channels; a working electrode, a counter electrode, and a reference electrode are disposed on the transparent conductive substrate; the surface of the working electrode is modified with a thin film of photoelectroactive material; the working electrode, the counter electrode, and the reference electrode are exposed within the microfluidic channels; The data processing module includes a data acquisition unit and a data processing unit. The data acquisition unit is electrically connected to the working electrode, the counter electrode, and the reference electrode, respectively, and is used to acquire photocurrent response values. The data processing unit is electrically connected to the data acquisition unit and is used to substitute the photocurrent response values ​​into a pre-established standard curve to obtain the equivalent value of the oxidizing component in the reaction solution.

[0014] The atmospheric particulate matter oxidation potential detection system, wherein the thickness of the photoelectric active material film is 0.1mm-0.5mm.

[0015] The atmospheric particulate matter oxidation potential detection system further includes a delivery module; the delivery module is connected to the microfluidic channel via a pipe and is used to deliver the test liquid into the microfluidic channel.

[0016] Beneficial Effects: This invention provides a method and system for detecting the oxidation potential of atmospheric particulate matter. The method includes the following steps: mixing a probe molecule solution with an atmospheric particulate matter solution, followed by incubation to obtain a reaction solution; injecting the reaction solution into a photoelectrochemical microfluidic chip with a three-electrode system to obtain a photocurrent response value; wherein the working electrode in the three-electrode system is modified with a photoactive material film; and substituting the photocurrent response value into a pre-established standard curve to obtain the equivalent value of the oxidizing component in the reaction solution, thereby realizing the detection of the oxidation potential of atmospheric particulate matter. This detection method combines a photoelectrochemical sensor and a microfluidic system to form a photoelectrochemical microfluidic chip, fully leveraging the synergistic advantages of both to construct a highly efficient analytical system. Furthermore, by utilizing the specific reaction between the oxidizing component in atmospheric particulate matter and the probe molecules, leading to the consumption of probe molecules or the generation of reactants, a quantitative change in the photocurrent signal is caused. Then, by utilizing the good linear quantitative relationship between the probe consumption and the photocurrent response value, the oxidation potential of atmospheric particulate matter is indirectly characterized by detecting the consumption of probe molecules, effectively avoiding interference from complex matrices on direct detection. Furthermore, this detection method has outstanding advantages such as high sensitivity, strong anti-interference ability and fast analysis speed, and can accurately quantify the oxidation potential of atmospheric particulate matter. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the process for detecting the oxidation potential of atmospheric particulate matter according to the present invention. Figure 2 This is a schematic diagram of a microchannel metal mold. Figure 3 A schematic diagram of the microfluidic chip fabrication process; Figure 4 This is a schematic diagram of a photoelectrochemical microfluidic chip. Figure 5 This is a schematic diagram of a real-time detection platform for microfluidic photoelectrochemical sensing. Figure 6 This is a schematic diagram of the DTT detection principle. Figure 7 XRD patterns of CdIn2S4 and MoS2; Figure 8 XPS plots for CdIn2S4 and MoS2; Figure 9 SEM images and mapping images of CdIn2S4 and MoS2; Figure 10 UV-Vis DRS plots and Mott-Schottky plots for CdIn2S4 and MoS2; Figure 11 Figure showing the optimized solid-liquid ratio data for CdIn2S4 and MoS2; Figure 12 Electrochemical impedance spectroscopy for ITO, ITO-CdIn2S4, and ITO-CdIn2S4-MoS2; Figure 13 The image shows the CV test results. Figure 14 This is a diagram showing the results of the feasibility analysis. Figure 15 A graph showing the establishment of the standard curve and optimization of reaction conditions based on the UV-DTT method; Figure 16 The standard curves for DTT and 1,4-NQ detection based on photoelectrochemical sensing are shown. Figure 17 This is a graph showing the parallel detection results of soluble components (WS) and insoluble components (WI) in actual atmospheric particulate matter samples. Detailed Implementation

[0018] This invention provides a method and system for detecting the oxidation potential of atmospheric particulate matter. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0020] Existing OP detection technologies are mainly divided into two categories: bioanalytical methods and chemical instrumental methods. Bioanalytical methods use alveolar macrophages as a model, quantifying ROS generation using the 2',7'-dichlorodihydrofluorescein (DCFH) fluorescent probe. While reflecting real biological reactions, they suffer from drawbacks such as long cell culture cycles (>24 hours), large batch-to-batch variability, and low throughput. Chemical instrumental methods include dithiothreitol (DTT) consumption methods, ascorbic acid (AA) methods, and electron paramagnetic resonance (EPR). Among these, the DTT method has become mainstream due to its good correlation with health effect markers, indirectly characterizing OP values ​​by detecting the DTT consumption rate. However, these methods generally rely on large laboratory equipment (such as UV-Vis spectrophotometers and high-performance liquid chromatography), require cumbersome sample pretreatment (extraction / derivatization), and take 2-6 hours to detect. Furthermore, different methods have varying sensitivities to ROS components (e.g., the DTT method is sensitive to quinones, while the AA method is sensitive to metal ions), making cross-sectional comparisons of results difficult. More importantly, existing technologies cannot meet the needs of rapid on-site detection, which severely restricts the application of OP index in real-time air quality early warning.

[0021] This invention, based on the integration of photoelectrochemistry (PEC) sensing and microfluidics, provides an innovative path to overcome the aforementioned bottlenecks. PEC technology utilizes the photoelectric conversion properties of semiconductor materials (such as TiO2 and SnO2): light excitation generates electron-hole pairs, and the analyte acts as an electron donor / acceptor, altering the interfacial charge transfer efficiency and causing changes in the photocurrent signal. Its "photoexcitation-electrodetection" separation mechanism pushes the detection limit to the picomolar level and offers advantages such as fast response (second-level) and low background noise. Microfluidics, through a micrometer-level channel network, integrates sample processing, reaction, and detection units, achieving five major breakthroughs with nanoscale fluid manipulation: high throughput (multi-channel parallel processing), high reproducibility (droplet isolation to prevent contamination), low reagent consumption (only 1 / 100th of traditional methods), rapid mixing (micro-vortex-enhanced mass transfer), and portability and automation. However, there are currently no reports of applying the integrated technology of photoelectrochemistry sensing and microfluidics to the detection of atmospheric particulate matter oxidation potential. The miniaturized analytical system formed by combining the two opens up a new path for rapid and sensitive detection of atmospheric toxicity.

[0022] Based on this, such as Figure 1As shown, the present invention provides a method for detecting the oxidation potential of atmospheric particulate matter, comprising the following steps: Step S10: Mix the probe molecule solution with the atmospheric particulate matter solution, and after incubation, obtain the reaction solution; Step S20: The reaction solution is injected into the photoelectrochemical microfluidic chip of the three-electrode system to obtain the photocurrent response value; wherein, the working electrode in the three-electrode system is modified with a thin film of photoactive material; Step S30: Substitute the photocurrent response value into the pre-established standard curve to obtain the equivalent value of the oxidizing component in the reaction solution, thereby realizing the detection of the oxidation potential of atmospheric particulate matter.

[0023] In this embodiment, the detection method combines a photoelectrochemical sensor with a microfluidic system to form a photoelectrochemical microfluidic chip, fully leveraging the synergistic advantages of both to construct a highly efficient analytical system. Furthermore, it utilizes the specific reaction between oxidizing components in atmospheric particulate matter and probe molecules, leading to the consumption of probe molecules or the generation of reactants, thereby causing quantitative changes in the photocurrent signal. Then, by utilizing the strong linear quantitative relationship between probe consumption and photocurrent response value, the oxidation potential of atmospheric particulate matter is indirectly characterized by detecting the amount of probe molecule consumed, effectively avoiding interference from complex matrices on direct detection. Moreover, this detection method has outstanding advantages such as high sensitivity, strong anti-interference ability, and fast analysis speed, enabling accurate quantification of the oxidation potential of atmospheric particulate matter.

[0024] Specifically, this invention effectively overcomes several drawbacks of traditional detection methods by synergistically integrating photoelectrochemical sensing and microfluidic technology. The microfluidic system enables precise sample manipulation and processing, significantly reducing reagent consumption; photoelectrochemical detection, with its inherent high sensitivity and anti-interference capabilities, eliminates the influence of sample turbidity and color. The combination of these two technologies allows this method to achieve rapid and low-cost detection while maintaining high sensitivity, significantly outperforming traditional methods. Furthermore, the photocurrent response versus concentration curve established in this invention exhibits a good linear relationship with the standard curve of traditional ultraviolet spectrophotometry, and the detection results of the two methods show a high degree of consistency. This dual validation not only ensures the scientific validity of the data but also provides strong evidence for the reliability of the method in practical applications. In addition, this invention unifies the expression of detection results in standard oxidant equivalent concentrations, establishing a standardized toxicity assessment system. Further analysis of the correlation between OP values ​​and specific chemical components such as total organic carbon, heavy metals, and anions using multivariate statistical methods not only enables comparison of toxicity intensity among samples from different sources but also provides important data support and scientific basis for tracing the main sources of atmospheric particulate matter toxicity. Furthermore, this method is not only applicable to precise laboratory analysis, but can also be extended to rapid on-site detection, demonstrating significant application value and broad development prospects in the fields of environmental monitoring and health risk assessment.

[0025] In some embodiments, the probe molecules in the probe molecule solution are selected from, but are not limited to, one or more of electron donor probes, electron acceptor probes, and enzyme-catalyzed reaction probes. Based on the diversity of probe molecules, by selecting different probe molecules, the detection method can be adapted to the detection requirements of different chemical components.

[0026] In some embodiments, the probe molecule is selected from, but not limited to, one or more of, dithiothreitol, glutathione, cysteine, ascorbic acid, dopamine, potassium ferrocyanide / potassium ferrocyanide, methylene blue, horseradish peroxidase-hydrogen peroxide (HRP-H2O2) system, superoxide dismutase (SOD), and catalase (CAT).

[0027] Specifically, the probe molecules mainly include, but are not limited to: (a) molecules that can act as electron donors (such as DTT, ascorbic acid, etc.) or electron acceptors, directly participating in the charge transfer process at the photoelectric interface; and (b) molecules or enzyme systems that can generate or consume certain electrochemically active products (such as hydrogen peroxide) through the OP reaction, thereby indirectly modulating the photocurrent signal. By establishing a quantitative functional relationship between the enhancement or reduction of the photocurrent signal (ΔI) after the reaction and the amount of probe consumed or product generated, the accurate and flexible determination of the oxidation potential of atmospheric particles can be achieved. This method provides an innovative and flexible detection solution for rapidly assessing the health risks of atmospheric particulate matter.

[0028] In some embodiments, the concentration of the probe molecule solution is 1 mM-3 mM; the volume ratio of the probe molecule solution to the atmospheric particulate matter solution is (4-8):1. After dissolving atmospheric particulate matter in water to form an atmospheric particulate matter solution, mixing the atmospheric particulate matter solution with an excess of probe molecules according to the above volume ratio allows all the oxidizing components in the atmospheric particulate matter solution to specifically react with the probe molecules, leading to the consumption of probe molecules or the generation of reactants, thereby causing a quantitative change in the photocurrent signal.

[0029] In a preferred embodiment, the volume ratio of the probe molecule solution to the atmospheric particulate matter solution is 5:1.

[0030] In some embodiments, the incubation treatment is carried out at a temperature of 20°C-40°C for a duration of 10 min-60 min. At this temperature and time, the probe molecules can undergo a redox reaction with the oxidizing components in the atmospheric particulate matter solution, thereby consuming the probe molecules.

[0031] In a preferred embodiment, the incubation treatment is performed at a temperature of 37°C for 30 minutes.

[0032] In some embodiments, the photoactive material film can be made of various types of semiconductor nanomaterials, such as metal oxides, metal sulfides, and carbon-based nanomaterials. This modified layer, as a key functional layer, efficiently generates and separates photogenerated carriers, providing a significantly enhanced photocurrent signal for detection, thus laying the foundation for high-sensitivity detection and achieving a high-performance photoelectrochemical sensing interface. Preferably, the material of the photoactive material film is selected from one or more of the following: CdIn2S4-MoS2 heterojunction, TiO2, ZnO, BiVO4, CdS, In2S3, CuInS2, g-C3N4, CsPbBr3, and BP.

[0033] In this embodiment, a layer-by-layer modification process is used to construct the CdIn2S4-MoS2 heterojunction photoelectric interface. First, CdIn2S4 is dispersed in a mixture of ethanol and perfluorosulfonic acid and drop-coated onto an ITO electrode to form a stable substrate layer. Then, a chitosan-glacial acetic acid dispersion of MoS2 is applied as the top layer, forming a robust composite structure. This layer-by-layer modification method significantly enhances the adhesion of the heterojunction material to the electrode surface through the cross-linking effect of the polymer materials, ensuring the stability of the material and preventing it from detaching during detection, thus providing a crucial guarantee for obtaining repeatable detection signals.

[0034] In some embodiments, step S30, the method for establishing the pre-established standard curve, includes the following steps: Step S31: Mix the quantitative probe molecule solution with standard oxidant solutions of gradient concentrations, and after incubation, obtain a series of reaction solutions; Step S32: Inject the series of reaction solutions into the photoelectrochemical microfluidic chip of the three-electrode system to obtain a series of photocurrent response values; Step S33: Establish a linear relationship between standard oxidant solutions of gradient concentrations and a series of photocurrent response values ​​as a standard curve.

[0035] In some embodiments, the standard oxidant solution is a 1,4-naphthoquinone (1,4-NQ) solution. Utilizing the favorable linear relationship between 1,4-NQ concentration and photocurrent response, the oxidation potential of atmospheric particulate matter is indirectly detected by obtaining this linear relationship. In actual sample detection, the sample is pretreated and then reacted with probe molecules. The detected photocurrent response is substituted into the obtained linear relationship, and the 1,4-NQ equivalent value (μM 1,4-NQ equiv) is used as the oxidation potential detection index to characterize the overall toxicity of atmospheric particulate matter.

[0036] In some implementations, the detection method is not limited to photoelectrochemical technology, but can also be extended to traditional electrochemical methods (such as current and impedance methods). Based on the excellent optical properties and fluid control capabilities of the microfluidic platform, efficient integration of optical detection modes such as photoluminescence and electrochemiluminescence can also be achieved, allowing for flexible selection of the optimal detection scheme according to the needs of different application scenarios.

[0037] In some embodiments, the application targets of the detection method are not limited to the detection of oxidation potential of atmospheric particulate matter. Based on the core principle of redox activity assessment of probe molecule consumption and signal changes, it can be extended to a variety of application scenarios: key applications include the detection of neurodegenerative disease risk factors in atmospheric particulate matter (such as transition metal ions copper, iron, and manganese, and organic neurotoxic substances such as polycyclic aromatic hydrocarbons and 1H-imidazo[4,5-c]pyridine-4-amine); it also covers fields such as food antioxidant capacity assessment, pharmaceutical active ingredient analysis, and monitoring of oxidative stress levels in biological fluids, demonstrating the wide applicability of the technology platform.

[0038] In addition, the present invention also provides a detection system for the oxidation potential of atmospheric particulate matter to implement the detection method, comprising: A photoelectrochemical microfluidic chip includes a polymer substrate with microfluidic channels formed on its surface, and a transparent conductive substrate disposed on the polymer substrate and located on one side of the microfluidic channels; a working electrode, a counter electrode, and a reference electrode are disposed on the transparent conductive substrate; the surface of the working electrode is modified with a thin film of photoelectroactive material; the working electrode, the counter electrode, and the reference electrode are exposed within the microfluidic channels; The data processing module includes a data acquisition unit and a data processing unit. The data acquisition unit is electrically connected to the working electrode, the counter electrode, and the reference electrode, respectively, and is used to acquire photocurrent response values. The data processing unit is electrically connected to the data acquisition unit and is used to substitute the photocurrent response values ​​into a pre-established standard curve to obtain the equivalent value of the oxidizing component in the reaction solution.

[0039] In this embodiment, a photoelectrochemical microfluidic chip is formed by combining a photoelectrochemical sensor and a microfluidic system, fully leveraging their synergistic advantages to construct a highly efficient analytical system. Furthermore, the specific reaction between oxidizing components in atmospheric particulate matter and probe molecules leads to the consumption of probe molecules or the generation of reactants, thereby causing quantitative changes in the photocurrent signal. Then, utilizing the strong linear quantitative relationship between probe consumption and photocurrent response value, the oxidation potential of atmospheric particulate matter is indirectly characterized by detecting probe molecule consumption through a data processing module, effectively avoiding interference from complex matrices on direct detection.

[0040] Specifically, this detection system is based on a photoelectrochemical microfluidic chip, combining semiconductor materials with a microfluidic chip system to achieve highly sensitive, interference-resistant, and rapid detection of the oxidation potential of atmospheric particulate matter. Furthermore, the photoelectrochemical microfluidic chip allows for the definition of electrode regions through patterning processes, the formation of microchannels from polymer materials, and surface treatment to achieve stable bonding. In addition, this invention achieves quantitative detection of signal intensity and probe consumption by establishing a detection probe molecule-induced photoelectric signal change. Moreover, this system can unify and quantify the toxicity of different component forms using standard oxidant equivalents per unit mass of particulate matter, and demonstrates accuracy and reliability even under complex matrix conditions, showcasing its application effectiveness in real-world environmental sample detection.

[0041] In some embodiments, the microfluidic channel is provided with an inlet, an outlet, and a drain outlet; when performing atmospheric particulate matter oxidation potential detection, the reaction solution enters the microfluidic channel through the inlet and is discharged through the outlet, and the drain outlet is in a closed state. The drain outlet is used to clean the microfluidic channel to increase the liquid discharge rate.

[0042] In some embodiments, the thickness of the photoactive material film is 0.1 mm to 0.5 mm. This thickness of photoactive material film can efficiently generate and separate photogenerated carriers, providing a significantly enhanced photocurrent signal for detection, thus laying the foundation for high-sensitivity detection and obtaining a high-performance photoelectrochemical sensing interface.

[0043] In some embodiments, the detection system further includes a delivery module; the delivery module is connected to the microfluidic channel via a pipe and is used to deliver the test liquid into the microfluidic channel.

[0044] In some embodiments, the fabrication of the photoelectrochemical microfluidic chip includes the following steps: 1) Preparation of polymer substrate with microfluidic channels on the surface: First, a curable polymer and a corresponding curing agent are mixed in proportion and injected into a mold with a microfluidic channel structure. Then, the mixture is placed in an oven at 60℃-90℃ for 20min-40min to allow it to be completely cured and formed. Subsequently, the cured substrate is processed to separate complete and independent chip units and form the necessary fluid interfaces. Preferably, the polymer prepolymer includes, but is not limited to, polydimethylsiloxane (PDMS) or other polymers with similar properties. The mass ratio of the polymer prepolymer to the curing agent is (8-10):1.

[0045] 2) Etching and modification of the substrate electrode: Selective etching is performed on the transparent conductive substrate with the aid of a mask to precisely define the regions of the working electrode, counter electrode and reference electrode; then, a thin film of photoactive material with a thickness of 0.1-0.5 mm and a concentration of 10-60 mg / mL is modified on the surface of the working electrode.

[0046] 3) Bonding and encapsulation of the microfluidic chip: Surface activation technology is employed, using an oxygen plasma cleaner to treat the bonding surfaces of the polymer substrate and the substrate electrode at 70-100W for 1-3 minutes to improve their surface energy and reactivity. Subsequently, the channel surfaces and electrode-modified surfaces of both are tightly bonded for 1-4 minutes to form an irreversible sealed connection, thereby constructing a closed chamber containing micron-level channels and integrated electrodes. This bonding scheme ensures the sealing and stability of the microfluidic system, effectively prevents liquid leakage, and guarantees sufficient contact between the sensing interface and the sample, achieving permanent integration of the microfluidic layer and the sensing electrode substrate.

[0047] 4) Integration of the microfluidic photoelectrochemical sensing platform: A photoelectrochemical microfluidic chip is fixed in place using a support structure. A standard three-electrode system is employed, with the electrode modified with a photoactive material film serving as the working electrode, along with a counter electrode and a reference electrode. A reliable connection to the electrochemical workstation is achieved via electrode clips. Simultaneously, the chip's fluid interface is connected to a syringe pump via a 0.5-1.3mm standard tubing, enabling automated sample transport. After verifying the system's sealing and fluid stability through flow path testing, the photoelectrochemical microfluidic chip, delivery module, and data processing module are finally integrated to construct a complete automated detection system.

[0048] In some implementations, the fabrication methods for microfluidic chips include, but are not limited to, soft lithography, injection molding, laser etching, and other microfabrication processes. Chip materials can be selected from various substrate materials such as PDMS, glass, and polymers, and the channel structure design can be customized according to specific detection requirements.

[0049] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention.

[0050] Example 1 Pour polydimethylsiloxane (PDMS) and curing agent into a disposable plastic cup at a mass ratio of 10:1, and stir thoroughly until dense small bubbles appear. Then place the cup in a vacuum desiccator connected to a vacuum pump to remove the bubbles (approximately 30-40 minutes). Pour the de-bubbled PDMS into a microchannel metal mold (e.g., ...). Figure 2As shown, place it in an oven and cure it at 85°C for 20 minutes to form a smooth PDMS substrate. Cut and correct it with a cutting knife, and punch holes with a 1.1mm punch for later use.

[0051] The microfluidic chip fabrication process is as follows: Figure 3 As shown, a metal mask with cutouts in the photoelectrochemical working electrode region and electrode connection region is sandwiched with an indium tin oxide (ITO) electrode substrate. Insulating ink is coated onto the cutouts, and the substrate is cured under 3kW UV light for 30 seconds. The conductive layer on the substrate electrode that is not coated with ink is removed by chemical etching. The etching solution composition is hydrochloric acid:water:nitric acid = 32:8:16 mL. After immersing the electrode in the etching solution for 20 minutes, it is rinsed with pure water and then immersed in 50 mL of acetone solution for 30 minutes to remove the ink. The ink-removed electrode substrate is then ultrasonically cleaned in anhydrous ethanol, removed, and dried in an oven for modification with photoelectroactive materials.

[0052] 0.1232 g of Cd(NO3)2·4H2O was dispersed in a mixed solution. After continuous sonication for 10 min, 0.3056 g of In(NO3)3·4.5H2O and 0.2404 g of thioacetamide were added, and the mixture was magnetically stirred for 20 min. The suspension was then placed in a 100 mL polytetrafluoroethylene-lined reactor and kept at 180 °C for 24 h. After cooling to room temperature, the mixture was immediately centrifuged and washed four times with deionized water and anhydrous ethanol. Finally, CdIn2S4 was obtained by vacuum drying at 60 °C for 12 h. 10 mg of CdIn2S4 was dissolved in 190 μL of ethanol and 10 μL of perfluorosulfonic acid membrane solution, and 5 mg of MoS2 was dissolved in a mixed solution of 990 μL of glacial acetic acid and 10 μL of pure water containing 2 mg of chitosan. The solutions were ultrasonically dispersed for 30 min. The mixture was then applied using a drop-coating method to a fixed exposure area of ​​0.28 cm². 2 After modifying the working electrode with CdIn2S4, it was dried at 60℃ for 8 hours, followed by modification with MoS2 and drying to complete the preparation of the CdIn2S4-MoS2 electrode.

[0053] With the PDMS substrate channel side up, place it and the CdIn2S4-MoS2 electrode into a plasma cleaner for bombardment. Set the program to 50 sccm, 80 W, and 1 min. After removing the PDMS substrate and electrode, align them and attach them together. Gently press the PDMS substrate surface to complete the irreversible seal between the PDMS and the glass, forming a leak-free closed system except for the injection channel. Figure 4 As shown.

[0054] After designing using CAD, a custom 3D-printed nylon platform substrate was created. Red and black copper wires were soldered to the blue LED beads using solder wire, connecting the switch, socket, resistor, and power supply. Finally, these components were embedded into the platform using hot melt adhesive. The prepared PDMS chip was then embedded. A syringe and reservoir were connected via a 1.1mm outer diameter steel needle and a Tygon tubing. A syringe pump was used to draw the sample into the detection platform to avoid cross-contamination and ensure stable microfluidic transport. Finally, electrode clips were connected to the designated electrode areas to create a three-electrode system. This system was then connected to a Chi660E electrochemical workstation to construct a high-precision microfluidic photoelectrochemical sensing real-time detection platform. (See attached image). Figure 5 As shown.

[0055] Utilizing the photoelectrochemically active material's ability to generate electron-hole pairs under illumination, the detection probe DTT can act as an electron donor, providing electrons to holes in CdIn2S4-MoS2, thereby reducing the recombination of photogenerated electron-hole pairs, increasing carrier transfer efficiency, and improving photocurrent response. This allows for real-time reflection of changes in DTT concentration. The DTT detection principle diagram is shown below. Figure 6 As shown, a band-matched heterojunction material is first synthesized and then steadily assembled onto the electrode interface using a layer-by-layer modification process to form a photoelectric active center. When an electron donor probe, DTT, is introduced into the system, it undergoes efficient electron transfer with photogenerated holes, effectively suppressing electron-hole recombination and thus significantly enhancing the anodic photocurrent response. The signal enhancement amplitude is quantitatively related to the DTT concentration. By detecting the photocurrent change caused by the remaining DTT after the reaction of oxidizing components, the indirect and sensitive detection of the oxidation potential of atmospheric particulate matter can be achieved.

[0056] The oxidation potential of DTT was determined to be 1.25 V using cyclic voltammetry (CV). The band structures of CdIn2S4 and MoS2 were obtained using UV-Vis DRS and Mott-Schottky spectroscopy. After analyzing the electron transfer mechanism, it was determined that CdIn2S4-MoS2 constitutes a Z-type heterojunction material with a hole potential of 1.40 V, which can be reduced by DTT. A good linear relationship was found between the photocurrent response and the gradient concentration of DTT, namely 0, 10, 25, 50, 100, 150, 200, 300, 400, 600, 800 and 1000 μM DTT. A model system was established using 1,4-naphthoquinone (1,4-NQ) as a standard oxidant. 150 μL of gradient concentrations (2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20, 22.5, and 25 μM 1,4-NQ solutions) were reacted with 750 μL of 1.2 mM DTT at 37 °C for 30 min, followed by photocurrent detection. The results showed that higher 1,4-NQ concentrations resulted in lower residual DTT concentrations and consequently lower photocurrent responses, demonstrating a good linear relationship between 1,4-NQ concentration and photocurrent response. By establishing this linear relationship between oxidant concentration and photocurrent response, the oxidation potential of atmospheric particulate matter can be indirectly detected.

[0057] In actual sample testing, the sample is pretreated and then reacted with DTT. The detected photocurrent response is substituted into the obtained linear relationship, and the 1,4-NQ equivalent value (μM 1,4-NQ equiv) is used as the oxidation potential detection index to characterize the comprehensive toxicity of atmospheric particulate matter. A 10cm sample is taken. 2 Actual atmospheric particulate matter samples were dissolved in 1 mL of pure water and subjected to ultrasonic extraction for 40 min. The mixture was then centrifuged at 10,000 rpm for 30 min. The supernatant was filtered through a 0.22 μm syringe filter to obtain the soluble components of the atmospheric particulate matter. The remaining suspension was lyophilized at -80 °C to concentrate the insoluble components. 150 μL of the soluble / insoluble component was reacted with 750 μL of 1.2 mM DTT at 37 °C for 30 min, and the oxidation potential of the actual sample was indirectly obtained by measuring the photocurrent response intensity. In addition, the pretreated soluble / insoluble components were simultaneously analyzed using a UV-Vis spectrophotometer. 50 μL of the soluble / insoluble component was reacted with 250 μL of DTT at 37 °C for 30 min, followed by the addition of 500 μL of 0.5 mM 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and thoroughly mixed. After color development for 2 min, the absorbance at a wavelength of 412 nm was measured. The feasibility and practicality of the photoelectrochemical sensing detection method were verified by comparing the results with those obtained from UV.

[0058] Furthermore, the feasibility of this scheme is verified by characterizing each stage of the preceding steps, as detailed below: 1) A microfluidic photoelectrochemical sensing system based on CdIn2S4-MoS2 heterojunction was constructed. First, the successful synthesis was confirmed by characterizing the two materials separately: X-ray diffraction (XRD) results are as follows. Figure 7 As shown, their diffraction patterns were compared with their respective standard cards, indicating that both materials were successfully synthesized. All diffraction peaks were sharp and free of impurities, demonstrating that the synthesized materials possess good crystallinity and phase purity. Furthermore, the patterns clearly displayed their respective characteristic diffraction peaks, confirming the integrity of the crystal structure.

[0059] X-ray photoelectron spectroscopy (XPS) such as Figure 8 As shown, where Figure 8 (a), (b), (c), and (d) represent S 2p, Mo 3d, In 3d, and Cd 3d, respectively. The results show that the characteristic binding energy peaks of S 2p, Mo 3d, In 3d, and Cd 3d all match the valence states, confirming the successful synthesis of the material with high purity. This means that the binding energy shifts of the characteristic elements were accurately measured, verifying the chemical state of the material surface.

[0060] Scanning electron microscope (SEM) images and mapping images of CdIn2S4 and MoS2 are shown below. Figure 9 As shown, the morphological characterization visually demonstrates the nanosheet-like layered structure of the material. Specifically, it is composed of... Figure 9 As shown in (a), CdIn2S4 exhibits a uniformly dispersed octahedral structure. Figure 9 As shown in (b) and (c), MoS2 exhibits a thin, stacked nanosheet structure. When modified with CdIn2S4-MoS2, it... Figure 9 In image (d), MoS2 nanosheets are observed stacked on the surface of the CdIn2S4 octahedral substrate, indicating successful fabrication of the heterojunction material. Furthermore, mapping analysis revealed the elemental composition and distribution of the CdIn2S4-MoS2 composite. S and Mo elements were widely distributed, with concentrated accumulation in the central region, while Cd and In elements were less abundant in the central region but uniformly distributed outside the center. This result indicates that CdIn2S4 and MoS2 form a heterostructure, providing charge transfer channels and significantly shortening the charge migration distance, thereby enhancing the photocatalytic activity of the composite material. Based on this, the UV-Vis DRS diagrams of CdIn2S4 and MoS2 are as follows: Figure 10As shown in (a) and (b), the UV-VisDRS diagrams reveal the absorption range of the material in the visible light region, from which the optical bandgap value is calculated; the Mott-Schottky distributions of CdIn2S4 and MoS2 are shown in... Figure 10 As shown in (c) and (d), curve analysis clarifies the carrier type of the semiconductor and calculates the accurate flat-band potential. The above band structure analysis collectively confirms that this system conforms to the electron transfer mechanism of a Z-type heterojunction, providing a theoretical basis for efficient charge separation. Furthermore, UV-Vis DRS confirmed the light absorption range of CdIn2S4 and MoS2, as shown in... Figure 10 As shown in (a) and (b), the calculated band gaps for both CdIn2S4 and MoS2, obtained based on the Tauc-plot, are 2.16 eV and 1.60 eV, respectively. The conduction band potentials (E0) of pure CdIn2S4 and MoS2 were further investigated using Mott-Schotky curves. CB ) and valence potential (E) VB The result is as follows Figure 10 As shown in (c) and (d), both are confirmed to be n-type semiconductors with a flat band potential (E). fB The voltages are -0.63V and 0.02V (vs. Ag / AgCl), which can be further converted to -0.43V and 0.22V (vs. NHE). Typically, the E of an n-type semiconductor... CB E fB -0.1V, therefore E CB These are -0.53V and 0.12V respectively. Furthermore, according to E... VB =E CB +E g The E values ​​of CdIn2S4 and MoS2 were determined. VB The values ​​are 1.63V and 1.72V respectively.

[0061] Regarding the interface construction process, a layer-by-layer modification strategy was adopted: first, an ethanol dispersion of CdIn2S4 was drop-coated onto an ITO substrate to form a bottom film; then, a chitosan-acetic acid solution of MoS2 was applied to cover it to construct a composite structure. The uniformity and stability of the modified layer were ensured through systematic optimization of the solid-liquid ratio. The optimized solid-liquid ratio data for CdIn2S4 and MoS2 are shown in the figure below. Figure 11 As shown. First, the CdIn2S4 system is optimized. Figure 11 (a) found that the electrode achieved the maximum photocurrent response when the solid-liquid ratio was 50 mg / mL. Based on this, with CdIn₂S₄ as the optimal solid-liquid ratio, further optimization of MoS₂ was performed, such as... Figure 11 In (b), when the solid-liquid ratio of MoS2 is 12.5 mg / mL, the heterojunction system exhibits a synergistic enhancement effect, with the photocurrent reaching a peak of 5.8 μA.

[0062] During the performance verification phase, the electrochemical impedance spectroscopy (EIS) plot is shown below. Figure 12 As shown, the tests revealed that the charge transfer impedance increased significantly with the increase of the modification layer; scanning electron microscopy (SEM) mapping visually demonstrated the uniform distribution of the two materials on the electrode surface, both of which jointly confirmed the successful assembly of the heterojunction. Finally, the modified electrode was permanently bonded to the PDMS microfluidic substrate through oxygen plasma treatment, completing the integrated assembly of the entire sensor chip. Furthermore, EIS analysis showed that as the electrode interface was constructed layer by layer from the ITO substrate, CdIn2S4 modification to the CdIn2S4-MoS2 heterojunction, the charge transfer impedance showed a regular increase. This trend confirmed that the optoelectronic materials of each layer were successfully modified on the electrode surface, and that the heterojunction structure effectively controlled the interfacial electron transport dynamics.

[0063] 2) A novel, highly sensitive photoelectrochemical detection method for oxidation potential was established. First, the oxidation potential of DTT on the CdIn2S4-MoS2 heterojunction electrode was measured to be approximately 1.26 V using CV. The CV test results are as follows: Figure 13 As shown, this potential is lower than the heterojunction valence band potential, thermodynamically confirming that DTT can be oxidized by photogenerated holes. Specifically, no obvious redox peaks were observed in the deoxygenated phosphate buffer (PB) solution. After the addition of DTT, an obvious irreversible oxidation peak appeared at approximately 1.35 V (vs. Ag / AgCl), which is attributed to the oxidation reaction of thiol groups in DTT. The oxidation peak current of DTT after deoxygenation treatment was significantly enhanced, and the peak potential shifted negatively to 1.26 V, confirming that dissolved oxygen participates in the oxidation process of DTT and interferes with the detection results.

[0064] The feasibility analysis results of the photocurrent response (PEC) of different modified electrodes were systematically evaluated, as shown in the figure below. Figure 14 As shown, the intensity follows an increasing order: MoS2 < MoS2-CdIn2S4 < CdIn2S4 < CdIn2S4-MoS2 < CdIn2S4-MoS2-DTT. This trend confirms that CdIn2S4 has superior photoelectric properties compared to MoS2. Constructing a CdIn2S4-MoS2 heterojunction can produce a significant synergistic enhancement effect, with its photocurrent response surpassing that of any single material. The introduction of DTT further significantly improves the signal response, verifying its crucial role as an electron donor in the photoelectric detection system. This verifies the photoelectric performance advantages of the heterojunction structure and the detection mechanism by which DTT, as an electron donor, captures photogenerated holes and suppresses electron-hole recombination, thereby enhancing the signal.

[0065] The standard curve established and reaction condition optimization data based on the UV-DTT method are shown in the figure below. Figure 15As shown, in the process of establishing the method, using classical ultraviolet spectrophotometry as a reference, a linear relationship between the 0-1 mM gradient concentration of DTT and absorbance was established based on the characteristic absorption peak at 412 nm after the reaction of DTT and DTNB. Figure 15 As shown in (a), the DTT concentration exhibits a strong positive correlation with absorbance in the range of 0-1 mM. Furthermore, using 1,4-NQ as the standard oxidant, kinetic studies optimized the reaction time to 30 minutes, at which point the reaction rate was fastest. Figure 15 As shown in (b), a quantitative 1 mM DTT was reacted with a gradient concentration of 1,4-NQ, and the remaining DTT was detected to obtain a standard curve of absorbance versus 1,4-NQ concentration. Figure 15 In (c), the correlation curve between 1,4-NQ concentration and absorbance established on this basis showed a significant negative correlation in the range of 1-25 μM. The experimental results verified the detection efficacy of the DTT method and provided a reliable reference for the comparative evaluation of PEC.

[0066] Based on this, the same series of samples were introduced into the photoelectrochemical microfluidic chip for detection via a syringe pump. This successfully constructed a standard curve between the 0-1 mM gradient concentration DTT and the photocurrent response, as shown in the figure. Figure 16 In (a), a linear relationship between the photocurrent response and the 1,4-NQ concentration in the range of 1-25 μM was also established. Figure 16 In (b), the detection limit reaches 0.03 μM, and the two photoelectric standard curves show high consistency with the corresponding UV method determination results. This method, by constructing a complete standard curve system, not only achieves rapid and accurate detection of DTT, but also indirectly completes sensitive analysis of oxidizing substances through the quantification of residual DTT, providing an effective technical means for reliable assessment of the oxidation potential of atmospheric particulate matter. Specifically, by… Figure 16 It can be seen that the DTT concentration exhibits a good linear relationship with the photocurrent response value in the range of 0-1 mM (R0). 2 >0.98); Based on this, the standard curve of 1,4-NQ concentration and relative photocurrent response (I / I0) established showed a significant linear relationship in the range of 1-25 μM (R0.98). 2 The detection limit was >0.998, and the detection limit was 0.03 μM. The results verified the ability of the PEC sensing method to quantitatively detect DTT and its residual concentration after reaction with the oxidant, providing a new approach for highly sensitive analysis of oxidation potential.

[0067] 3) Accurate assessment and correlation analysis of the oxidation potential of actual atmospheric particulate matter samples were completed. The system collected 39 PM data sets from the same location on three random days each month from January 2023 to January 2024. 2.5The samples underwent ultrasonic extraction, centrifugation, and filtration of the supernatant to obtain water-soluble components. The precipitate was then lyophilized and concentrated to obtain water-insoluble components. These components were then detected using ultraviolet (UV) and photoelectrochemical (PET) sensing methods, respectively. The measured values ​​were substituted into a standard curve to quantify the oxidation potential as an equivalent 1,4-NQ concentration (μM equiv). Parallel detection results of soluble (WS) and insoluble (WI) components in actual atmospheric particulate matter samples were presented. Figure 17 The results from the PEC and UV methods show good consistency. The trends in the detection values ​​of WS and WI obtained by the two methods are highly consistent, and their numerical ranges are quite similar.

[0068] A systematic comparison of the detection results from the two methods revealed a significant positive correlation between the measured values ​​of 39 sample groups. Further paired t-test analysis showed no significant difference between the two methods (p>0.05), and Bland-Altman analysis showed that the data points fell within the agreement limit of mean ± 1.96 standard deviations, confirming good quantitative consistency between the two sets of data. Furthermore, despite the fundamental differences in the physicochemical properties of the WS and WI components, the PEC method showed no significant deviation among different components, fully demonstrating its excellent adaptability and reliability in complex environmental samples, and its detection effect is unaffected by the component solubility characteristics. Based on this, a correlation study was conducted by quantitatively analyzing the chemical components such as organic carbon and heavy metals in the samples, combined with meteorological and air quality data collected during the collection period. Multivariate statistical analysis showed a significant positive correlation between specific heavy metal components (such as Cu and Cd) and oxidation potential values. Simultaneously, relative humidity, wind speed, and PM2.5 were also found to be significantly positively correlated. 2.5 The mass concentrations were significantly correlated with oxidation potential, revealing the combined influence of climate conditions and human activities on particulate matter toxicity. This embodiment demonstrates that the photoelectrochemical sensing microfluidic chip can rapidly and accurately assess the oxidation potential of actual samples, and its results are in good agreement with classical methods. It also exhibits outstanding advantages such as strong resistance to matrix interference, convenient operation, and low cost, providing a reliable technical means for atmospheric particulate matter toxicity assessment and showing good application prospects and development potential in the field of environmental health risk assessment.

[0069] In summary, this invention provides a method and system for detecting the oxidation potential of atmospheric particulate matter. The method includes the following steps: mixing a probe molecule solution with an atmospheric particulate matter solution, followed by incubation to obtain a reaction solution; injecting the reaction solution into a photoelectrochemical microfluidic chip with a three-electrode system to obtain a photocurrent response value; wherein the working electrode in the three-electrode system is modified with a photoactive material film; and substituting the photocurrent response value into a pre-established standard curve to obtain the equivalent value of the oxidizing component in the reaction solution, thereby realizing the detection of the oxidation potential of atmospheric particulate matter. This detection method combines a photoelectrochemical sensor and a microfluidic system to form a photoelectrochemical microfluidic chip, fully leveraging the synergistic advantages of both to construct a highly efficient analytical system. Furthermore, by utilizing the specific reaction between the oxidizing component in atmospheric particulate matter and the probe molecules, leading to the consumption of probe molecules or the generation of reactants, a quantitative change in the photocurrent signal is caused. Then, by utilizing the good linear quantitative relationship between the probe consumption and the photocurrent response value, the oxidation potential of atmospheric particulate matter is indirectly characterized by detecting the amount of probe molecule consumed, effectively avoiding interference from complex matrices on direct detection. Furthermore, this detection method has outstanding advantages such as high sensitivity, strong anti-interference ability and fast analysis speed, and can accurately quantify the oxidation potential of atmospheric particulate matter.

[0070] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for detecting the oxidation potential of atmospheric particulate matter, characterized in that, Including the following steps: The probe molecule solution was mixed with an atmospheric particulate matter solution, and after incubation, a reaction solution was obtained. The reaction solution was injected into a photoelectrochemical microfluidic chip with a three-electrode system to obtain a photocurrent response value; wherein, the working electrode in the three-electrode system was modified with a thin film of photoactive material; By substituting the photocurrent response value into a pre-established standard curve, the equivalent value of the oxidizing component in the reaction solution is obtained, thereby realizing the detection of the oxidation potential of atmospheric particulate matter.

2. The method for detecting the oxidation potential of atmospheric particulate matter according to claim 1, characterized in that, The probe molecules in the probe molecule solution are selected from one or more of electron donor probes, electron acceptor probes, and enzyme catalytic reaction probes.

3. The method for detecting the oxidation potential of atmospheric particulate matter according to claim 2, characterized in that, The probe molecule is selected from one or more of the following: dithiothreitol, glutathione, cysteine, ascorbic acid, dopamine, potassium ferrocyanide / potassium ferrocyanide, methylene blue, horseradish peroxidase-hydrogen peroxide system, superoxide dismutase, and catalase.

4. The method for detecting the oxidation potential of atmospheric particulate matter according to claim 1, characterized in that, The concentration of the probe molecule solution is 1 mM-3 mM; the volume ratio of the probe molecule solution to the atmospheric particulate matter solution is (4-8):

1.

5. The method for detecting the oxidation potential of atmospheric particulate matter according to claim 1, characterized in that, The incubation temperature is 20℃-40℃, and the incubation time is 10min-60min.

6. The method for detecting the oxidation potential of atmospheric particulate matter according to claim 1, characterized in that, The material of the photoelectric active material film is selected from one or more of the following: CdIn2S4-MoS2 heterojunction, TiO2, ZnO, BiVO4, CdS, In2S3, CuInS2, g-C3N4, CsPbBr3, and BP.

7. The method for detecting the oxidation potential of atmospheric particulate matter according to claim 1, characterized in that, The method for establishing the pre-established standard curve includes the following steps: A series of reaction solutions were obtained by mixing quantitative probe molecule solutions with standard oxidant solutions of gradient concentrations and then incubating them. The series of reaction solutions were injected into a photoelectrochemical microfluidic chip with a three-electrode system to obtain a series of photocurrent response values; A linear relationship was established between standard oxidant solutions of gradient concentrations and a series of photocurrent response values, which served as a standard curve.

8. A detection system for the oxidation potential of atmospheric particulate matter used to implement the detection method as described in any one of claims 1-7, characterized in that, include: A photoelectrochemical microfluidic chip includes a polymer substrate with microfluidic channels formed on its surface, and a transparent conductive substrate disposed on the polymer substrate and located on one side of the microfluidic channels; A working electrode, a counter electrode, and a reference electrode are disposed on the transparent conductive substrate; the surface of the working electrode is modified with a thin film of photoactive material; the working electrode, the counter electrode, and the reference electrode are exposed within the microfluidic channel; The data processing module includes a data acquisition unit and a data processing unit. The data acquisition unit is electrically connected to the working electrode, the counter electrode, and the reference electrode, respectively, and is used to acquire photocurrent response values. The data processing unit is electrically connected to the data acquisition unit and is used to substitute the photocurrent response values ​​into a pre-established standard curve to obtain the equivalent value of the oxidizing component in the reaction solution.

9. The system for detecting the oxidation potential of atmospheric particulate matter according to claim 8, characterized in that, The thickness of the photoelectric active material film is 0.1mm-0.5mm.

10. The detection system for the oxidation potential of atmospheric particulate matter according to claim 8, characterized in that, The detection system also includes a delivery module; the delivery module is connected to the microfluidic channel via a pipe and is used to deliver the test liquid into the microfluidic channel.

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