Small photoacoustic-photothermal dual-mode detection device and dopamine detection method thereof

Abstract

The invention discloses a small photoacoustic-photothermal dual-mode detection device and a dopamine detection method thereof, and belongs to the field of optical detection.The device comprises a light source used for exciting photoacoustic and photothermal signals of a sample, and the light source is a laser; the sample pool is made of polytetrafluoroethylene, a round hole is formed in the left side and provided with a rubber plug, the round hole is inwards communicated with the cylindrical sample cavity, and the right side is communicated with the cavity; the miniature microphone is assembled in the right side cavity and is used for receiving a sound signal; the preamplifier is connected with the miniature microphone; the oscilloscope is connected with the pre-amplifier and is used for collecting photoacoustic signals; the thermal imager is used for collecting the photo-thermal signals; the component bracket is divided into an upper layer, a middle layer and a lower layer which are respectively used for fixing the thermal imager, the sample pool for assembling the miniature microphone and the laser; the upper end and the lower end of the sample cavity penetrate through each other and are sealed through a circular quartz plate. The detection accuracy is improved through complementary signal output.

Description

Technical Field

[0001] The present invention belongs to the field of optical detection technology, and in particular relates to a small photoacoustic-photothermal dual-mode detection device and a dopamine detection method thereof. Background Art

[0002] Optical detection technology has a wide range of applications in drug analysis, clinical diagnosis, food testing and other fields. In recent years, photoacoustic detection technology has received widespread attention due to its unique advantages. This technology performs quantitative analysis by detecting the acoustic wave signal generated after the substance absorbs modulated light or a pulsed light source. The signal intensity depends only on the amount of light absorbed and is not affected by reflected or scattered light. Therefore, it shows significant advantages in multiphase systems (such as gas, liquid and solid) and strong scattering media. At present, a variety of detection devices and methods based on photoacoustic technology have been developed, such as the photoacoustic-microphone array system for highly sensitive detection of chloroform gas, the fiber-optic photoacoustic system for blood heparin analysis, and the acoustic standing wave-assisted photoacoustic flow cytometry system for detecting melanoma cells.

[0003] Although photoacoustic detection technology has many advantages, its single signal output is easily interfered with by environmental factors, resulting in reduced accuracy and reliability of detection results. To improve performance, research on dual-mode detection technologies based on photoacoustic-fluorescence and photoacoustic-ultrasound has also made some progress. However, current dual-mode platforms still have problems such as complex operation and large equipment size. Research on miniaturized and integrated dual-mode detection devices for biomolecules (such as dopamine) is still relatively limited. Summary of the Invention

[0004] To solve the above technical problems, the present invention proposes a small photoacoustic-photothermal dual-mode detection device, which improves detection accuracy through complementary signal output and expands its application potential in diverse detection scenarios.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a small photoacoustic-photothermal dual-mode detection device, comprising:

[0006] A light source, used to stimulate photoacoustic and photothermal signals of the sample, wherein the light source is a laser;

[0007] The sample pool is made of polytetrafluoroethylene, with a circular hole on the left side and a rubber stopper installed. The circular hole is connected to the cylindrical sample cavity inward and connected to the cavity on the right side;

[0008] a miniature microphone, mounted in the right cavity, for receiving acoustic signals;

[0009] a preamplifier connected to the miniature microphone;

[0010] an oscilloscope, connected to the preamplifier, for collecting photoacoustic signals;

[0011] A thermal imager, used to collect the photothermal signal;

[0012] A component bracket, divided into three layers: upper, middle, and lower, for respectively fixing the thermal imager, the sample cell equipped with a micro-microphone, and the laser;

[0013] The sample cavity light window structure is penetrated at the upper and lower ends of the sample cavity and is sealed by a circular quartz plate.

[0014] Preferably, the structure of the sample pool satisfies:

[0015] The sample cavity is coaxially centered with the microphone assembly cavity;

[0016] The sample cavity forms a double optical window through the quartz plate, allowing the laser to penetrate the sample in both directions.

[0017] Preferably, the three-layer structure of the component bracket is:

[0018] The thermal imager is fixed on the upper layer, facing the quartz light window on the top of the sample cell;

[0019] Middle layer fixed sample pool;

[0020] The laser is fixed on the lower layer, facing the quartz light window at the bottom of the sample cell.

[0021] Preferably, the device further comprises an origami sample carrier, said origami sample carrier comprising:

[0022] The first PVC composite board is provided with a plurality of circular holes, in which filter paper sheets treated with chitosan are fixed as reaction modules;

[0023] The second PVC composite board is provided with a plurality of circular holes, in which untreated filter paper sheets are fixed as detection modules;

[0024] The first PVC composite board and the second PVC composite board are fixed on the base sheet at intervals, and a double-sided adhesive area is provided on the right side of the base sheet as an auxiliary bonding module.

[0025] In a second aspect, the present invention further provides a dopamine detection method using a small photoacoustic-photothermal dual-mode detection device. Based on the device described in the first aspect, the method comprises the following steps:

[0026] preparing a CuS / g-C3N4 nanomaterial, and mixing the nanomaterial with a TMB solution to form a detection probe;

[0027] constructing a reaction module and a detection module using an origami platform, and fixing the detection probe on the detection module;

[0028] The dopamine solution to be tested was added dropwise to the reaction module. After drying, 15 μL of 100 mM hydrogen peroxide solution was added dropwise. The origami platform was then immediately folded to allow the reaction module to contact the detection module for reaction.

[0029] The reaction detection module is transferred to the sample pool, and the photoacoustic signal and the photothermal signal are excited by the light source;

[0030] Photoacoustic signals are collected through a micro-microphone, and photothermal signals are collected through a thermal imager;

[0031] The dopamine concentration was calculated based on the changes in the photoacoustic and photothermal signals.

[0032] Preferably, the preparation method of the CuS / g-C3N4 nanomaterial comprises:

[0033] Calcinate urea at high temperature to generate g-C3N4;

[0034] Disperse g-C3N4 in deionized water, add CuCl2 and TAA solution, and stir to react to generate CuS / g-C3N4 nanomaterials.

[0035] Preferably, the preparation steps of the detection probe include:

[0036] 15 mM TMB solution was mixed with 0.5 mg / mL CuS / g-C3N4 suspension at a volume ratio of 1:1;

[0037] 15 μL of the mixed solution was dropped onto the detection module and dried.

[0038] Preferably, the construction of the origami platform includes:

[0039] A reaction module and a detection module are set on a PVC plate, and a filter paper with chitosan added is fixed on the reaction module;

[0040] Dopamine solution and hydrogen peroxide solution were added dropwise to the reaction module, and a mixed solution of TMB and CuS / g-C3N4 was added dropwise to the detection module.

[0041] Preferably, the step of collecting the photoacoustic signal includes:

[0042] The filter paper after the reaction is placed in the sample pool and irradiated with a laser;

[0043] The acoustic signal is received by a miniature microphone, amplified by a preamplifier and then recorded by an oscilloscope.

[0044] Preferably, the step of collecting the photothermal signal includes:

[0045] The reacted filter paper is placed on top of the quartz plate on the sample cell and irradiated with a laser;

[0046] Use the mobile phone thermal imager to record temperature changes and obtain photothermal signals.

[0047] Compared with the prior art, the present invention has the following advantages and technical effects:

[0048] The present invention provides a small photoacoustic-photothermal dual-mode detection device, comprising: a light source for exciting photoacoustic and photothermal signals of a sample, wherein the light source is a laser; a sample cell made of polytetrafluoroethylene, with a circular hole provided on the left side and a rubber stopper installed, the circular hole being connected inwardly to a cylindrical sample cavity and being connected on the right side to a cavity; a miniature microphone assembled in the right cavity and being used to receive acoustic signals; a preamplifier connected to the miniature microphone; an oscilloscope connected to the preamplifier and being used to collect photoacoustic signals; a thermal imager for collecting the photothermal signals; a component bracket, divided into three layers: upper, middle, and lower, for respectively fixing the thermal imager, the sample cell equipped with the miniature microphone, and the laser; and a sample cavity light window structure, with the upper and lower ends of the sample cavity penetrating and sealed by a circular quartz plate.

[0049] The present invention reflects the characteristics of sound waves through photoacoustic signals and characterizes temperature changes through photothermal signals. The two physical dimensions complement each other and improve anti-interference performance.

[0050] The present invention integrates three layers (laser / sample cell / thermal imager) of the sample cell and the bracket, eliminating the need for an external complex optical path. The device is miniaturized and portable, and the entire device can be handheld and operated, making it suitable for bedside diagnosis, on-site rapid testing, and other scenarios (such as banana peel extract testing).

[0051] The origami carrier of the present invention realizes "reaction-detection" integration: the reaction is triggered by folding contact without the need for pumps, valves or liquid transfer; in addition, dual signal acquisition shares the same sample pool and laser source, and only the position of the filter paper needs to be adjusted, which simplifies the operation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0053] Figure 1 Schematic diagram of detection according to an embodiment of the present invention;

[0054] Figure 2 Schematic diagram of the structure of an embodiment of the present invention, wherein A is a schematic diagram of the structure of the detection device; B is a schematic diagram of the origami sample carrier; C is a TEM image of g-C3N4 (a) and CuS / g-C3N4 (b);

[0055] Figure 3 Schematic diagram of the detection results, where A shows the changes in oxTMB under different dopamine concentrations; B is the relationship curve between dopamine concentration and photoacoustic signal; C is the relationship curve between dopamine concentration and photothermal signal. DETAILED DESCRIPTION

[0056] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0057] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0058] First, the technical terms involved in the following embodiments are explained.

[0059] TMB: 3,3',5,5'-tetramethylbenzidine;

[0060] oxTMB: oxidized 3,3',5,5'-tetramethylbenzidine;

[0061] CuS / g-C3N4: copper sulfide / graphite phase carbon nitride material;

[0062] TAA: thioacetamide.

[0063] Example 1

[0064] CuS / g-C3N4 exhibits peroxidase activity, catalyzing the TMB-H2O2 system to produce oxTMB, which generates a strong photoacoustic and photothermal signal. Dopamine, on the other hand, discolors oxTMB, thereby reducing the photoacoustic signal. The constructed origami platform and dual-mode detection device enable quantitative analysis of dopamine.

[0065] like Figure 1 As shown, this embodiment provides a small photoacoustic-photothermal dual-mode detection device, including a light source, a sample cell, a miniature microphone, a preamplifier, an oscilloscope, a thermal imager, a component bracket, and a sample cavity light window structure, specifically including:

[0066] A light source, used to stimulate photoacoustic and photothermal signals of the sample, wherein the light source is a laser;

[0067] Specifically, the light source is an 808 nm laser, which provides the energy required to excite the sample's photoacoustic and photothermal signals.

[0068] The sample pool is made of polytetrafluoroethylene, with a circular hole on the left side and a rubber stopper installed. The circular hole is connected to the cylindrical sample cavity inward and connected to the cavity on the right side;

[0069] Furthermore, the structure of the sample pool satisfies:

[0070] The sample cavity is coaxially centered with the microphone assembly cavity;

[0071] The sample cavity forms a double optical window through the quartz plate, allowing the laser to penetrate the sample in both directions.

[0072] Specifically, the sample pool holds the sample and is made of polytetrafluoroethylene. Its length, width and height are 45mm, 22mm and 22mm respectively. A circular hole with a diameter of 14mm and a length of 9mm is drilled on the left side of the pool body and a rubber plug is installed. The left hole is connected to a cylindrical cavity with a diameter of 6mm and a height of 6mm, which serves as the sample cavity. The right side is connected to a cavity with a diameter of 14mm and a length of 25mm, which is used to assemble a miniature microphone. All holes and cavities are axially centered. The upper and lower ends of the sample cavity are hollowed out and sealed with a circular quartz plate with a diameter of 14mm and a thickness of 1mm as a light window to allow the light source to illuminate the sample.

[0073] a miniature microphone, mounted in the right cavity, for receiving acoustic signals;

[0074] a preamplifier connected to the miniature microphone;

[0075] an oscilloscope, connected to the preamplifier, for collecting photoacoustic signals;

[0076] A thermal imager, used to collect the photothermal signal;

[0077] Specifically, a miniature microphone is connected to a preamplifier and installed in the sample pool to receive acoustic signals; the other end of the preamplifier is connected to an oscilloscope to collect photoacoustic signals; and the photothermal signal is obtained by thermal imaging of a mobile phone.

[0078] The component bracket is divided into three layers: upper, middle and lower, which respectively fix the thermal imager, the sample cell equipped with a micro microphone and the laser; Figure 2 As shown in A.

[0079] Furthermore, the three-layer structure of the component bracket is:

[0080] The thermal imager is fixed on the upper layer, facing the quartz light window on the top of the sample cell;

[0081] Middle layer fixed sample pool;

[0082] The laser is fixed on the lower layer, facing the quartz light window at the bottom of the sample cell.

[0083] The sample cavity light window structure is penetrated at the upper and lower ends of the sample cavity and is sealed by a circular quartz plate.

[0084] The present embodiment also includes an origami sample carrier, the origami sample carrier comprising:

[0085] The first PVC composite board is provided with a plurality of circular holes, in which filter paper sheets treated with chitosan are fixed as reaction modules;

[0086] The second PVC composite board is provided with a plurality of circular holes, in which untreated filter paper sheets are fixed as detection modules;

[0087] The first PVC composite board and the second PVC composite board are fixed on the base sheet at intervals, and a double-sided adhesive area is provided on the right side of the base sheet as an auxiliary bonding module.

[0088] Specifically, in the sample carrier, a hole was punched on Whatman No. 3 filter paper with a hole punch to obtain a small disc with a diameter of 6.0 mm. 10 μL of chitosan solution (0.8% of 2% acetic acid solution) was added to the small disc. After drying at room temperature (25°C) for 10 minutes, the above operation was repeated once and the disc was placed in a 37°C oven for drying for 1 hour to obtain a good film-forming effect.

[0089] Punch three holes of 6.0 mm in diameter evenly on a PVC plate of 1.0 × 2.5 cm in size, and glue the punched PVC plate to another complete PVC base plate with double-sided tape. Fix the filter paper with chitosan added in the circular holes as the reaction module of the origami device. Make another PVC composite plate in the same way, and fix the untreated filter paper disc in the circular hole as the detection module of the origami device. Glue the two PVC plates on a 3.4 × 2.5 cm paper piece in the order of reaction module and detection module, with a 2 mm gap in the middle. Leave an area of ​​1.0 × 2.5 cm on the right side for sticking double-sided tape as an auxiliary bonding module, as shown in the figure. Figure 2 As shown in B.

[0090] Example 2

[0091] This embodiment also provides a dopamine detection method using a small photoacoustic-photothermal dual-mode detection device. Based on the device described in Example 1, the method includes the following steps:

[0092] S1, preparing CuS / g-C3N4 nanomaterials, and mixing the nanomaterials with TMB solution to form a detection probe;

[0093] Furthermore, the preparation method of the CuS / g-C3N4 nanomaterial includes:

[0094] Calcinate urea at high temperature to generate g-C3N4;

[0095] Disperse g-C3N4 in deionized water, add CuCl2 and TAA solution, and stir to react to generate CuS / g-C3N4 nanomaterials.

[0096] Specifically, the preparation of CuS / g-C3N4 nanomaterials:

[0097] 40.00 g of urea was placed in a muffle furnace at 10 °C min -1The mixture was heated to 800°C at a rate of 100°C and then cooled for 10 min to obtain light yellow g-C3N4.

[0098] Weigh 25.00 mg of g-C3N4 and disperse it in 5 mL of deionized water. Ultrasonicate for 30 min until the dispersion is uniform. Add 33.60 mg of CuCl2 while stirring and stir vigorously in a 60 ° C water bath. -1 TAA solution was quickly injected into the above solution and stirred for 10 min to obtain a dark green precipitate. Centrifuge at 6000 rpm for 5 min and wash the precipitate with deionized water. TEM of g-C3N4 and CuS / g-C3N4, as shown in Figure 2 Figure 2 As shown in a and b in C.

[0099] Furthermore, the preparation steps of the detection probe include:

[0100] Mix 15 mM TMB solution and 0.5 mg / mL CuS / g-C3N4 suspension in a volume ratio of 1:1; add 15 μL of the mixed solution to the detection module and dry it.

[0101] S2. constructing a reaction module and a detection module using an origami platform, and fixing the detection probe on the detection module;

[0102] Furthermore, the construction of the origami platform includes:

[0103] A reaction module and a detection module are set on a PVC plate, and a filter paper with chitosan added is fixed on the reaction module;

[0104] Dopamine solution and hydrogen peroxide solution were added dropwise to the reaction module, and a mixed solution of TMB and CuS / g-C3N4 was added dropwise to the detection module.

[0105] Specifically, 20 μL of 10 mM, pH 6.5 phosphate buffer solution was added to the origami reaction module filter paper. After drying in a 37°C oven for 10 minutes, 15 μL of dopamine solution (solvent: 10 mM, pH 6.5 phosphate buffer solution) was added to the reaction module filter paper and dried at 37°C for 15 minutes. 15 μL of a mixed solution (15 mM TMB solution and 0.5 mg / mL CuS / g-C3N4 suspension in a 1:1 volume ratio) was added to the detection module filter paper and dried at 37°C for 15 minutes. 15 μL of 100 mM hydrogen peroxide solution (solvent: 100 mM, pH 3.5 phosphate buffer solution) was added to the reaction module filter paper. The left reaction module and the right detection module were folded, and the right auxiliary bonding module was folded to fix them to maintain contact between the reaction module and the detection module. After drying in a 37°C oven for 5 minutes, the filter paper was removed from the origami device and continued to dry.

[0106] S3. Add the dopamine solution to be tested dropwise to the reaction module. After drying, add 15 μL of 100 mM hydrogen peroxide solution dropwise. Immediately thereafter, fold the origami platform so that the reaction module contacts the detection module to allow for reaction.

[0107] S4, transferring the reaction detection module to the sample pool, and using a light source to stimulate photoacoustic signals and photothermal signals;

[0108] Specifically, the filter paper was transferred to the sample cell. A laser with a wavelength of 808 nm, a power of 180 mW, and a frequency of 6 Hz was used to irradiate the sample for 1 minute. A microphone was used to collect the photoacoustic signal, and an oscilloscope was used to display the signal. The filter paper was then transferred to the top of the quartz plate in the sample cell. A laser with a wavelength of 808 nm, a power of 590 mW, and an irradiation time of 40 seconds was used. A thermal imager was used to collect the photothermal signal. Three samples were measured in parallel.

[0109] S5, collecting photoacoustic signals through a micro microphone and collecting photothermal signals through a thermal imager;

[0110] Furthermore, the photoacoustic signal collection step includes:

[0111] The filter paper after the reaction is placed in the sample pool and irradiated with a laser;

[0112] The acoustic signal is received by a miniature microphone, amplified by a preamplifier and then recorded by an oscilloscope.

[0113] Furthermore, the step of collecting the photothermal signal includes:

[0114] The reacted filter paper is placed on top of the quartz plate on the sample cell and irradiated with a laser;

[0115] Use the mobile phone thermal imager to record temperature changes and obtain photothermal signals.

[0116] S6. Calculate the concentration of dopamine based on the changes in the photoacoustic signal and the photothermal signal.

[0117] Specifically, under the optimal conditions of this embodiment, as the dopamine concentration increases, the color of oxTMB gradually becomes lighter, as shown in FIG. Figure 3 As shown in A in Figure 1. The linear range of photoacoustic detection of dopamine is 50-700 μM, the linear regression equation is Y=0.40C+10.16, and the detection limit is 18 μM. Figure 3 As shown in Figure B. The linear range of photothermal detection of dopamine is 100-800 μM, the linear regression equation is Y=0.03C+2.76, and the detection limit is 30 μM. Figure 3 As shown in C.

[0118] Example:

[0119] Sample 1: Artificial blood; Sample 2: Artificial urine; Sample 3: Banana peel extract. Artificial blood and urine were diluted 100-fold with 10 mM phosphate buffer, pH 6.5, before use. Banana peel extract was prepared as a 100 mg / mL stock solution and then diluted 100-fold. The recovery and relative standard deviation were determined according to the dopamine standard solution assay procedure described above. The dopamine detection results in the samples are shown in Table 1.

[0120] Table 1

[0121]

[0122] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A small photoacoustic-photothermal dual-mode detection device, characterized in that: The following steps are involved: A light source, used to stimulate photoacoustic and photothermal signals of the sample, wherein the light source is a laser; The sample pool is made of polytetrafluoroethylene, with a circular hole on the left side and a rubber stopper installed. The circular hole is connected to the cylindrical sample cavity inward and connected to the cavity on the right side; a miniature microphone, mounted in the right cavity, for receiving acoustic signals; a preamplifier connected to the miniature microphone; an oscilloscope, connected to the preamplifier, for collecting photoacoustic signals; A thermal imager, used to collect the photothermal signal; A component bracket, divided into three layers: upper, middle, and lower, for respectively fixing the thermal imager, the sample cell equipped with a micro-microphone, and the laser; The sample cavity light window structure is penetrated at the upper and lower ends of the sample cavity and is sealed by a circular quartz plate.

2. The device according to claim 1, characterized in that The structure of the sample pool satisfies: The sample cavity is coaxially centered with the microphone assembly cavity; The sample cavity forms a double optical window through the quartz plate, allowing the laser to penetrate the sample in both directions.

3. The device according to claim 1, characterized in that The three-layer structure of the component bracket is: The thermal imager is fixed on the upper layer, facing the quartz light window on the top of the sample cell; Middle layer fixed sample pool; The laser is fixed on the lower layer, facing the quartz light window at the bottom of the sample cell.

4. The device according to claim 1, characterized in that Also included is an origami sample carrier comprising: The first PVC composite board is provided with a plurality of circular holes, in which filter paper sheets treated with chitosan are fixed as reaction modules; The second PVC composite board is provided with a plurality of circular holes, in which untreated filter paper sheets are fixed as detection modules; The first PVC composite board and the second PVC composite board are fixed on the base sheet at intervals, and a double-sided adhesive area is provided on the right side of the base sheet as an auxiliary bonding module.

5. A dopamine detection method using a small photoacoustic-photothermal dual-mode detection device, characterized in that: Based on the device according to any one of claims 1 to 4, the method comprises the following steps: preparing a CuS / g-C3N4 nanomaterial, and mixing the nanomaterial with a TMB solution to form a detection probe; constructing a reaction module and a detection module using an origami platform, and fixing the detection probe on the detection module; The dopamine solution to be tested was added dropwise to the reaction module. After drying, 15 μL of 100 mM hydrogen peroxide solution was added dropwise. The origami platform was then immediately folded to allow the reaction module to contact the detection module for reaction. The reaction detection module is transferred to the sample pool, and the photoacoustic signal and the photothermal signal are excited by the light source; Photoacoustic signals are collected through a micro-microphone, and photothermal signals are collected through a thermal imager; The dopamine concentration was calculated based on the changes in the photoacoustic and photothermal signals.

6. The method according to claim 5, characterized in that The preparation method of the CuS / g-C3N4 nanomaterial comprises: Calcinate urea at high temperature to generate g-C3N4; Disperse g-C3N4 in deionized water, add CuCl2 and TAA solution, and stir to react to generate CuS / g-C3N4 nanomaterials.

7. The method according to claim 5, characterized in that The preparation steps of the detection probe include: 15 mM TMB solution was mixed with 0.5 mg / mL CuS / g-C3N4 suspension at a volume ratio of 1:1; 15 μL of the mixed solution was dropped onto the detection module and dried.

8. The method according to claim 5, characterized in that The construction of the origami platform includes: A reaction module and a detection module are set on a PVC plate, and a filter paper with chitosan added is fixed on the reaction module; Dopamine solution and hydrogen peroxide solution were added dropwise to the reaction module, and a mixed solution of TMB and CuS / g-C3N4 was added dropwise to the detection module.

9. The method according to claim 5, characterized in that The photoacoustic signal collection step includes: The filter paper after the reaction is placed in the sample pool and irradiated with a laser; The acoustic signal is received by a miniature microphone, amplified by a preamplifier and then recorded by an oscilloscope.

10. The method according to claim 5, characterized in that The photothermal signal collection step includes: The reacted filter paper is placed on top of the quartz plate on the sample cell and irradiated with a laser; Use the mobile phone thermal imager to record temperature changes and obtain photothermal signals.

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