Dual-mode optical fiber sensor and glyphosate content determination and photo-thermal controlled release green conversion system and method

Abstract

The invention discloses a dual-mode optical fiber sensor and a glyphosate content determination and photo-thermal controlled release green conversion system and method. The integrated double-optical-fiber sensor capable of realizing specific detection and efficient degradation of glyphosate pollution comprises a first sensor for realizing glyphosate detection through local plasma resonance and a second sensor for realizing glyphosate degradation through a photothermal effect of a nano material layer. The glyphosate inhibits an enzymatic reaction of tyrosinase on the first sensor, causing an output spectral peak change. The detected solution releases glyphosate oxidoreductase through photo-thermal excitation of the second sensor, glyphosate is degraded into aminomethylphosphonic acid and glyoxylic acid, a degradation solution is generated and recycled for the first sensor, and multiple times of cyclic detection and degradation are achieved. The method has the advantages of simplicity and convenience in operation, small size, high detection sensitivity, low detection limit and the like, the glyphosate pollution detection and treatment efficiency is remarkably improved, and the method has good environmental protection property and economical efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of optobiomonitoring, and particularly relates to a dual-mode fiber optic sensor and a glyphosate content determination and photothermal controlled-release green conversion system and method. Background Art

[0002] Glyphosate is the most widely used broad-spectrum herbicide globally, especially in the large-scale cultivation of glyphosate-resistant genetically modified crops (such as glyphosate-resistant corn, soybeans, etc.). On the one hand, as a non-selective and total-vegetation herbicide, glyphosate and its derivatives cause extensive pollution when deposited in water bodies. Long-term exposure to glyphosate can lead to various human health hazards. The World Health Organization states that the glyphosate content in drinking water should not exceed 0.7 mg / L. With the increasing resistance of weeds to glyphosate, the application dosage has increased, exacerbating the residue risk. On the other hand, glyphosate has chemical properties such as strong polarity, easy ionization in water, and easy complexation with metal ions, and has no chromophore and fluorophore, making its extraction and quantitative analysis in complex matrices extremely difficult.

[0003] Although traditional detection methods (such as gas chromatography, high-performance liquid chromatography, etc.) have high sensitivity, they require cumbersome pretreatment such as filtration, extraction, and concentration, and rely on high-end instruments and professional personnel, making it difficult to achieve rapid and convenient on-site detection. In addition, existing glyphosate degradation technologies mainly rely on physical adsorption and chemical methods, which have the risk of secondary release of pollution or low degradation efficiency. In contrast, microbial enzyme catalysis has the advantage of being green and environmentally friendly, but due to the limited release and action process, the efficiency is low.

[0004] Therefore, studying an integrated detection and degradation technology that requires no complex pretreatment, has high detection sensitivity, high degradation efficiency, and is environmentally friendly is of great practical significance for the monitoring and green conversion of glyphosate pollution. Summary of the Invention

[0005] In view of the existing technical problems of glyphosate detection and degradation, the present invention provides a dual-mode fiber optic sensor and a glyphosate content determination and photothermal controlled-release green conversion system and method, which can realize the integration of specific detection and efficient degradation of glyphosate pollution.

[0006] To achieve the object of the present invention, the technical solutions provided by the present invention are as follows:

[0007] First Aspect

[0008] The present invention provides a dual-mode fiber optic sensor, and the dual fiber optic sensor includes a first sensor for glyphosate detection through local surface plasmon resonance and a second sensor for glyphosate degradation through the photothermal effect of a nanomaterial layer.

[0009] Further, both the first sensor and the second sensor are constructed based on micro-nano optical fibers;

[0010] The micro-nano optical fiber includes: a tapered transition region for exciting high-order modes and thus generating coupling phenomena between different modes, and a uniform waist region with a significant evanescent field.

[0011] A structure guiding layer, a noble metal layer, and a nano material layer are sequentially arranged in the uniform waist region;

[0012] The structure guiding layer uses polydopamine (PDA) to coat the surface of the micro-nano optical fiber, providing stable chemical bonding for subsequent accumulated layers;

[0013] The noble metal layer is composed of silver nanoparticles (AgNPs) with a thickness of 40 nm - 60 nm, and is solidified on the surface of the structure guiding layer;

[0014] The nano material layer is composed of PDA@AgNPs nanoparticles, which have a high specific surface area and abundant surface active sites, and are used to enhance the molecular binding stability and detection sensitivity.

[0015] Further, the active sites of the nano material layer of the first sensor are further combined with tyrosinase (TYR) for specific binding with glyphosate molecules; wherein, the first sensor measures the glyphosate concentration by monitoring the change in the wavelength of the interference spectrum peak: under the action of the first laser input by the broadband light source, local surface plasmon resonance is generated and the molecular binding signal is enhanced; glyphosate inhibits the enzymatic reaction of TYR, causing a change in the interference spectrum peak of the fiber waist region.

[0016] Further, the nano material layer of the second sensor is further assembled with GOX and agarose layer (AG); under the action of a pump light source with a wavelength of 808 nm, the photothermal effect of the nano material is generated; wherein, the photothermal effect causes the AG layer to disintegrate, releasing GOX to catalyze the degradation of glyphosate; glyphosate is catalytically degraded into aminomethylphosphonic acid and glyoxylic acid, completing the green transformation of the polluted liquid.

[0017] Further, the structure guiding layer, the noble metal layer, and the nano material layer are prepared according to the following steps:

[0018] Structure guiding layer: Using ethanol as a solvent, dissolve an appropriate amount of dopamine in 75% ethanol, adjust the pH to strong alkalinity with 5M sodium hydroxide, the color of the solution gradually changes from colorless to dark black, stir and then dialyze, and freeze-dry to obtain PDA powder; disperse the PDA powder in an appropriate amount of deionized water to obtain a dopamine solution; then immerse the uniform waist region of the prepared sensing optical fiber in the freshly prepared dopamine solution and react for an appropriate time to obtain a PDA-coated sensing optical fiber;

[0019] Noble metal layer: Dissolve 0.34 g of ascorbic acid in 100 ml of deionized water, take 1 mL and put it into beaker A. Dissolve 0.25 g of sodium citrate in 10 mL of deionized water, take 1 mL and put it into beaker A. Add 32 mL of deionized water to beaker A, stir to dissolve it fully, adjust the pH value between 7.0 - 8.0 with 0.2 m sodium citrate / 0.05 m sodium carbonate, stir magnetically at 900 rpm and heat in a water bath at 30 °C, gradually raise the temperature, add 0.32 mL of 0.1 m AgNO3 solution, take out the reaction solution after reacting for 20 min, cool it and place it in a centrifuge to wash repeatedly to obtain an AgNPs suspension. Then immerse the uniform waist area of the prepared sensing optical fiber in the freshly prepared AgNPs suspension, react for an appropriate time to obtain a noble metal-coated sensing optical fiber;

[0020] Nanomaterial layer: Immerse the sensing optical fiber coated with PDA@AgNPs in TYR solution or reductase solution to obtain a sensing optical fiber coated with a nanomaterial layer.

[0021] Furthermore, the diameter of the uniform waist area of the first sensor and the second sensor is 1 - 3 μm.

[0022] In the second aspect

[0023] The present invention provides a glyphosate content determination and photothermal controlled-release green conversion system, which includes the dual-mode fiber optic sensor as described above, as well as a pump light source, a first coupler, a first pipeline, a first reaction cell, a second pipeline, a second coupler, a spectrometer, a broadband light source, an optical switch, a third pipeline, a fourth pipeline, a liquid storage tank, and a second reaction cell;

[0024] Among them, the optical path transmission system includes the broadband light source, the optical switch, the first coupler and the second coupler, the first sensor, the second sensor, and the spectrometer;

[0025] The output optical signal of the pump light source is merged into the first sensor through the first coupler. The first sensor detects the glyphosate content, and the generated optical signal is converged and transmitted to the spectrometer through the second coupler to complete the acquisition of the content detection signal;

[0026] Another optical signal of the optical switch is input into the second sensor. The second sensor receives the photothermal signal and transmits the optical change signal generated during the degradation process to the spectrometer through the second coupler to realize the acquisition of the glyphosate degradation signal;

[0027] Finally, the optical path completes the closed-loop transmission of the glyphosate content detection and the degradation signal acquisition;

[0028] Among them, the liquid flow system includes a liquid storage tank, a first reaction cell, a second reaction cell, a first pipeline, a second pipeline, a third pipeline, and a fourth pipeline;

[0029] The left side of the liquid storage tank stores glyphosate polluted liquid, which is poured into the first reaction tank through the first pipeline; after the glyphosate solution in the first reaction tank is detected by the first sensor, it flows into the right side of the liquid storage tank as the recycled liquid;

[0030] The recycled liquid is input into the second reaction tank through the fourth pipeline. In the second reaction tank, the glyphosate is degraded by using the photothermal effect generated by the pump light source and the second sensor to generate the degraded liquid; the degraded liquid flows back to the left side of the liquid storage tank through the third pipeline to complete the degradation cycle of the polluted liquid;

[0031] The liquid flow system realizes the detection of glyphosate through the first reaction tank, realizes the photothermal degradation of glyphosate through the second reaction tank, and finally completes the detection and green degradation conversion of the glyphosate polluted liquid.

[0032] In the third aspect

[0033] The present invention provides a method for determining the glyphosate content and photothermal controlled-release green conversion. The method is based on the above-mentioned system and includes the following steps:

[0034] Step 1: Place the dual-mode fiber optic sensor in the reaction tank made of epoxy resin and fix it by irradiating with a UV glue ultraviolet lamp; input the first laser to the tapered micro-nano fiber interferometer to generate an evanescent wave and interference, and monitor the interference peak wavelength of the interference light. When the interference peak wavelength changes, it is determined that glyphosate exists in the system to be measured, then go to Step 2, otherwise there is no glyphosate;

[0035] Step 2: Switch the laser light source and input the second laser to the tapered micro-nano fiber interferometer to excite the photothermal effect of the nano material layer for photothermal controlled release.

[0036] Further, the method includes establishing a linear relationship between the glyphosate concentration and the change amount of the interference peak wavelength; establishing a linear relationship between the photothermal effect and the glyphosate degradation conversion rate to evaluate the green conversion result;

[0037] Inject glyphosate polluted liquid with different concentrations into the first reaction tank, input the first laser to the first sensor to generate an evanescent wave and interference, and monitor the interference peak wavelength of the interference light to establish a linear regression equation between the glyphosate concentration and the change amount of the interference peak wavelength;

[0038] Inject glyphosate polluted liquid into the second reaction tank, input the second laser to the second sensor to generate a photothermal effect, establish the relationship between the photothermal effect and the glyphosate degradation conversion rate, input the first laser to generate an evanescent wave and interference, monitor the change of the interference peak wavelength of the interference light, and after substituting the interference peak into the linear regression equation, determine the glyphosate content after degradation.

[0039] Furthermore, the light source of the first laser is a broadband light source with a wavelength band of 1250 - 1650 nm; the light source of the second laser is a pump light source with a wavelength of 808 nm and a power of 40 - 160 mW.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] 1. In the present invention, a double - conical multimode micro - nano fiber interferometer is used as a sensing optical fiber and fused with a single - mode optical fiber. By utilizing the interaction between the large surface evanescent field and surface substances, the refractive index change caused by the binding of target molecules can be detected. By using the local surface plasmon effect and thickness regulation of PDA@AgNPs, the resonance enhancement ability of AgNPs is optimized, the evanescent wave energy is enhanced, and at the same time, the surface area for glyphosate binding is increased. Compared with the micro - nano fiber interferometer without the modification of the nanomaterial layer, the technology proposed in the present invention realizes the enhancement of the fiber - optic sensing sensitivity; during the detection process, not only is the detection sample label - free, but also it has the advantages of simplicity and rapidity.

[0042] 2. Compared with traditional organophosphorus detection methods, the present invention can quickly detect the concentration of glyphosate in water and crops, thus contributing to human health. Compared with current gas chromatography, high - performance liquid chromatography, enzyme - linked immunosorbent assay, and inductively coupled plasma mass spectrometry, etc., it has a low detection limit, high sensitivity, and the device is simple and small. It eliminates the need for large, expensive instruments and repeated operations such as purification, concentration, and labeling, and can realize the specific detection of TYR for glyphosate.

[0043] 3. The present invention adopts a fiber - optic sensing device, which has the advantages of high sensitivity, small and flexible, and anti - electromagnetic radiation compared with traditional electrochemical sensors. Therefore, in - situ monitoring of glyphosate - contaminated liquid can be realized.

[0044] 4. The present invention adopts photothermal controlled release. By inputting an 808 - nm pump laser into the sensor, the photothermal effect of PDA@AgNPs is excited, the surface of the fiber - optic sensing probe is heated, and AG decomposes and releases degradation elements, realizing the green conversion of glyphosate; advanced oxidants or initiators (reactive oxygen species, persulfate, and light irradiation) can be used to improve the dephosphorization efficiency and continuously reduce the cost of wastewater treatment.

[0045] 5. The degradation of organophosphorus pesticides is an effective measure for environmental remediation, and their detection is a preventive tracking before remediation. The dual - mode fiber - optic sensing device can realize the detection of glyphosate content and continuous monitoring of cyclic conversion. The integrated system can monitor the sample in real - time and quickly obtain the detection results. This is particularly important for on - site applications (farmland monitoring, rapid food safety testing) that require rapid judgment and evaluation of pesticide residues.

[0046] 6. As a tiny and highly flexible optical component, the microfiber can be combined with different recognition substances to detect multiple parameters of environmental pollutants (microplastics, pesticides, antibiotics, air pollutants, viruses, bacteria). It can not only detect the presence or absence of specific biomarkers, but also provide more detailed biological information according to the different forms of biomarkers. The present invention provides an efficient, sensitive and multifunctional detection tool, which has important significance and broad application prospects for environmental pollution control, removal of pesticide residues in agricultural products, and microbial degradation research.

[0047] In summary, the purpose of the present invention is to provide a dual-mode optical fiber sensor to achieve the detection and green conversion of glyphosate content. By designing the sensor, introducing nanomaterials, optimizing the recognition element and photothermal effect, the deficiencies of the current device in detection sensitivity, reliability, low-concentration detection and anti-interference ability are solved. It not only realizes the sensitive detection and green degradation of glyphosate, but also provides an efficient, economical and sustainable solution for the environmental remediation of organophosphorus pesticides. This method will help improve the detection efficiency of pesticides in food and water, ensure public health and environmental safety, and has important scientific value and practical application significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic structural diagram of the dual-mode optical fiber sensor provided by the embodiment of the present invention;

[0049] Figure 2 is a schematic diagram of the principle of the sensing optical fiber in the embodiment of the present invention;

[0050] Figure 3 is a schematic diagram of the preparation of the first sensor modified with PDA-Ag NPs-TYR and the second sensor modified with PDA-Ag NPs-GOX-AG in the embodiment of the present invention;

[0051] Figure 4 is a schematic structural diagram of the reaction cell provided by the embodiment of the present invention;

[0052] Figure 5 is a schematic diagram for measuring the diameter of the uniform waist region of the optical fiber under a microscope after the multi-mode optical fiber is tapered in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0054] Example 1

[0055] As shown in Figures 2 - 3 Figure 4, it is a schematic structural diagram of a dual-mode fiber optic sensor provided by an embodiment of the present invention. A dual-mode fiber optic sensor provided by this embodiment includes a first fiber optic sensor 4 and a second fiber optic sensor 13;

[0056] Among them, the first sensor and the second sensor include a single-mode-multimode micro-nano-single-mode structured optical fiber, that is, single-mode optical fibers 16 are fused to both sides of the micro-nano optical fiber prepared from multimode optical fiber; the micro-nano optical fiber prepared from multimode optical fiber is a double-tapered micro-nano optical fiber, including tapered transition regions 17 and 19 on both sides and a uniform waist region 18, and its uniform waist region is the sensing region; a structure guiding layer, a noble metal layer, and a glyphosate recognition nanomaterial layer are sequentially arranged upward from the uniform waist region of the double-tapered micro-nano optical fiber in the sensing region.

[0057] It should be noted that for the single-mode-multimode micro-nano-single-mode structured optical fiber, due to the structural differences between the single-mode optical fiber and the multimode optical fiber, the transmitted light enters the multimode optical fiber from the single fundamental mode in the single-mode optical fiber and excites multiple modes, generating denser interference fringes. A small environmental change (such as temperature, refractive index) can cause a significant spectral shift, thereby improving the sensitivity of the sensor; there are more modes participating in the coupling in the multimode optical fiber, and the effective refractive indices between different modes are different. They interfere with each other during the transmission process, forming a multimode interference effect. The frequent energy exchange between modes increases the degree of nonlinearity of the response, making the modulation of the optical signal by the external environment more significant.

[0058] The multimode micro-nano is made by tapering the multimode optical fiber, making the diameter of the multimode optical fiber reach the micro-nano level. More optical energy diffuses out in the form of evanescent waves and comes into full contact with the external environment. Therefore, the large penetration depth of the evanescent field can effectively enhance the refractive index sensing sensitivity.

[0059] Preferably, a structure guiding layer, a noble metal layer, a glyphosate degradation nano layer, and a photothermal disintegration layer are sequentially arranged upward from the uniform waist region of the second sensor.

[0060] The structure guiding layer cures PDA in the uniform waist region;

[0061] The noble metal layer cures AgNPs on the structure guiding layer, and its thickness is 8-20 nm;

[0062] The glyphosate recognition nanomaterial layer fixes complex TYR on the noble metal layer of the first sensor;

[0063] The glyphosate degradation nano layer fixes GOX on the noble metal layer of the second sensor;

[0064] The photothermal disintegration layer solidifies the low melting point AG on the glyphosate degradation nanolayer.

[0065] The localized surface plasmon resonance enhancement effect described in the present invention refers to the resonance of free electrons on the surface of AgNPs under the action of light, forming a highly concentrated electromagnetic field, greatly improving the light absorption efficiency, and significantly enhancing the evanescent wave energy on the surface of the sensing optical fiber, which is conducive to the perception of the optical fiber sensor to small changes in the surface refractive index, thereby achieving higher sensitivity and lower detection limit.

[0066] The photothermal controlled release mentioned in the present invention refers to the efficient controlled release of nanomaterials by thermal effect under light excitation, so as to achieve on-demand supply, precise delivery, improve material utilization rate and reduce environmental pollution.

[0067] Specifically, the micro-nano optical fiber waist region of the first sensor 4 self-assembles PDA, AgNPs and TYR for detecting glyphosate concentration; the micro-nano optical fiber waist region of the second sensor self-assembles PDA, AgNPs, GOX and AG for photothermal degradation of glyphosate. Glyphosate inhibits the enzymatic reaction of TYR on the first sensor 4, causing the output spectrum peak to change. Glyphosate inhibits the enzymatic reaction on the first sensor 4, causing the output spectrum peak position to change, thereby realizing sensitive detection. The solution after detection releases GOX through photothermal excitation of the second sensor 13, degrading glyphosate into aminomethylphosphonic acid and glyoxylic acid, generating a degradation solution, which is recycled back to the first sensor 4, realizing multiple cycles of detection and degradation. The present invention has the advantages of simple operation, compact device, high detection sensitivity, low detection limit, etc., significantly improves the detection and treatment efficiency of glyphosate pollution, and has good environmental protection and economy.

[0068] Specifically, the first sensor 4 of the self-assembled PDA@AgNPs@TYR includes a micro-fiber Mach-Zehnder interferometer and polydopamine 21, silver nanoparticles 22 and tyrosinase 23; the second sensor 13 of the self-assembled PDA@AgNPs@Gox@AG includes a micro-fiber Mach-Zehnder interferometer and polydopamine 21, silver nanoparticles 22, and glyphosate oxidoreductase 24 encapsulated in agarose gel 26 for identifying glyphosate 25.

[0069] The preparation method is as follows:

[0070] A microfiber Mach-Zehnder interferometer is fabricated by fusion tapering. A multimode step-index fiber with a core diameter of 62.5 μm and a cladding diameter of 125 μm is fused and tapered into a fiber optic sensing probe, which is then fusion spliced with a single-mode fiber to form a microfiber Mach-Zehnder interference structure. In this embodiment, the diameter of the interferometer is 1 - 3 μm. Preferably, the diameter in this embodiment is 2.42 μm. This fiber diameter can not only ensure that the optical field has sufficient evanescent field to interact with metal nanoparticles, but also ensure the mechanical strength of the sensing fiber and prevent it from being easily broken by liquid impact. Figure 5 It is a measurement diagram of the uniform waist region diameter of the fiber optic after multimode fiber tapering provided by the present invention under a microscope.

[0071] (1) Preparation of polydopamine

[0072] Dissolve 50 mg of dopamine in 25 mL of 75% ethanol, add 5 M sodium hydroxide dropwise to adjust the pH to 11.5, stir at room temperature for 30 minutes, dialyze for 24 hours and then dry to obtain PDA powder. Disperse 20 mg of the prepared PDA powder in 10 mL of deionized water, and after ultrasonic dispersion, a PDA solution with a concentration of 2 mg / mL is obtained.

[0073] It should be noted that PDA can endow nanoparticles with appropriate biocompatibility and stability. The preparation method of the structure guiding layer is as follows: Immerse the uniform waist region of the prepared sensing fiber in the freshly prepared PDA solution for an appropriate reaction time to obtain a sensing fiber uniformly coated with PDA.

[0074] (2) Preparation of AgNPs

[0075] Dissolve 0.34 g of ascorbic acid in 100 ml of deionized water, take 1 mL and put it into beaker A. Dissolve 0.25 g of sodium citrate in 10 mL of deionized water, take 1 mL and put it into beaker A. Add 32 mL of deionized water to beaker A, stir to dissolve it fully, adjust the pH value between 7.0 - 8.0 with 0.2 m of sodium citrate, stir magnetically and then heat in a water bath. Add 0.32 mL of 0.1 m AgNO3 solution during the heating process, keep the reaction for 20 min, then take out the reaction solution, cool it and place it in a centrifuge for repeated washing to obtain an AgNPs suspension.

[0076] It should be noted that the preparation method of the noble metal layer is as follows: Immerse the uniform waist region of the prepared sensing fiber in the freshly prepared AgNPs suspension for an appropriate reaction time to obtain a sensing fiber coated with noble metal.

[0077] (3) Preparation of AG gel and the photothermal disintegration layer of the second sensor

[0078] Weigh 0.8 g of agarose powder and place it in a conical flask or beaker suitable for microwave heating. Add 100 mL of TAE or TBE buffer solution, and gently stir it with a glass rod to disperse it evenly. Place the mixture in the microwave oven and heat it for 15 - 20 seconds each time. After each heating, take out the solution and stir it thoroughly with a glass rod to prevent AG deposition or local overheating. Repeat the heating and stirring process 3 - 4 times until the solution is clear and completely dissolved. After the temperature of the AG solution slightly decreases (such as 40 - 50 °C), take an appropriate amount of the solution and soak the surface of the sensing optical fiber to ensure uniform coating, and then place it at room temperature to cool and solidify for 30 minutes.

[0079] It should be noted that the preparation method of the nanomaterial layer of the first sensor is as follows:

[0080] Immerse the sensing optical fiber coated with PDA@AgNPs in the TYP solution to obtain a sensing optical fiber coated with a nanomaterial layer.

[0081] It should be noted that the preparation method of the nanomaterial layer of the second sensor is as follows:

[0082] Immerse the sensing optical fiber coated with PDA@AgNPs in the GOX solution to obtain a sensing optical fiber coated with a nanomaterial layer.

[0083] Fabrication of the first sensor: Immerse the waist region of the micro - optical fiber in the PDA solution, AgNPs suspension, and TYR solution in sequence, and self - assemble to form PDA@AgNPs@TYR;

[0084] Fabrication of the second sensor: Prepare the waist region of the optical fiber using the same steps, and then coat GOX and AG gels, and cool and solidify to form PDA@AgNPs@Gox@AG. Connect the optical path in the order of Figure 1 to complete the fabrication of a dual - mode fiber optic sensor.

[0085] Example 2

[0086] As Figure 1 shown, this example provides a glyphosate content determination and photothermal controlled - release green conversion system, including the dual - mode fiber optic sensor in Example 1, as well as a pump light source 1, a coupler 2, a first pipeline 3, a first reaction cell 5, a second pipeline 6, a first coupler 7, a spectrometer 8, a broadband light source 9, an optical switch 10, a third pipeline 11, a fourth pipeline 12, a liquid storage tank 14, and a second reaction cell 15.

[0087] Specifically, the optical path transmission system consists of a broadband light source 9, an optical switch 10, a first coupler 2, a second coupler 7, a first sensor 4, a second sensor 13, a spectrometer 8, and related connection components: The output optical signal of the pump light source 1 is merged into the first sensor 4 through the coupler 2. The first sensor detects the glyphosate content, and the generated optical signal is converged and transmitted to the spectrometer 8 through the coupler 7 to complete the acquisition of the content detection signal. Another optical signal of the optical switch 10 is input into the second sensor 13. This sensor receives the photothermal signal and transmits the optical change signal generated during the degradation process to the spectrometer 8 through the coupler 7 to achieve the acquisition of the glyphosate degradation signal.

[0088] Finally, the optical path completes the closed-loop transmission of the glyphosate content detection and degradation signal acquisition.

[0089] The liquid flow system includes a liquid storage tank 14, a first reaction tank 5, a second reaction tank 15, a first pipeline 3, a second pipeline 6, a third pipeline 11, and a fourth pipeline 12, where: The left side of the liquid storage tank 14 stores the glyphosate contaminated liquid, which is poured into the first reaction tank 5 through the pipeline 3. After the glyphosate solution in the first reaction tank is detected by the first sensor 4, it flows into the right side of the liquid storage tank as the recycled liquid.

[0090] The recycled liquid is input into the second reaction tank 15 through the pipeline 12. In the second reaction tank, the glyphosate is degraded using the photothermal effect generated by the pump light source 1 and the second sensor 13 to generate the degraded liquid.

[0091] The degraded liquid flows back to the left side of the liquid storage tank through the third pipeline 11 to complete the degradation cycle of the contaminated liquid. This flow system realizes the glyphosate detection through the first reaction tank and the photothermal degradation of glyphosate through the second reaction tank, and finally completes the detection and green degradation transformation of the glyphosate contaminated liquid.

[0092] As Figure 4 shown, the contaminated liquid, recycled liquid, and degraded liquid flow into the reaction tank through the liquid inlet 27, incubate and are detected with the sensing optical fiber in the irrigation cavity 28, and then flow out through the liquid outlet 29.

[0093] Furthermore, the light source of the first laser is a broadband light source with a wavelength band of 1250 - 1650 nm; the light source of the second laser is a pump light source with a wavelength band of 808 nm and a power of 40 - 160 mW.

[0094] Example 3

[0095] This example provides a method for determining the glyphosate content and photothermal controlled-release green transformation. The method is based on the above system and includes the following steps:

[0096] Step 1: Place the dual-mode fiber optic sensor in a reaction cell made of epoxy resin. The first sensor and the second sensor are respectively fixed in the first reaction cell and the second reaction cell, and are fixed by irradiating with a UV glue ultraviolet lamp. Input the first laser into the tapered micro-nano fiber interferometer using an optical switch to generate an evanescent wave and interference, and monitor the interference peak wavelength of the interference light. When the interference peak wavelength changes, it is determined that glyphosate exists in the system to be measured, and then proceed to Step 2; otherwise, glyphosate does not exist.

[0097] Step 2: Switch the laser light source, and the optical switch switches the first laser to the second sensor. Input the second laser into the tapered micro-nano fiber interferometer to excite the photothermal effect of the nanomaterial layer for photothermal controlled release.

[0098] The test sample recovery liquid in the liquid storage tank flows into the second perfusion tank for glyphosate degradation. Inject an 808nm pump light to excite the photothermal effect of the second sensor, release the encapsulated GOX, and degrade glyphosate into low-toxic intermediate products (such as carbamic acid and phosphate). The degradation process is green and environmentally friendly without secondary pollution. At the same time, enable the optical switch to inject a broadband light source and monitor the glyphosate content simultaneously.

[0099] Specifically, for the quantitative test of glyphosate 25, as follows:

[0100] In a 1.5 mL centrifuge tube, sequentially add 500 μL of PBS (10 mmol / L, pH = 7) buffer solution and 200 μL of glyphosate solutions with different concentrations. Inject glyphosate contaminated solutions with different concentrations from the first reaction cell respectively, and after each measurement, inject an ethanol solution into the reaction cell, and repeatedly clean the sensing fiber and the sample cell by ultrasonic oscillation. Then inject 5 ml of AgNPs suspension and TYR solution into the sample cell, incubate for 30 min, and then inject ethanol for repeated washing, and then conduct the concentration detection of the next group of glyphosate contaminated solutions. For the inhibitory effect of glyphosate on tyrosinase, the more glyphosate is added, the stronger the inhibitory effect, and the change in the refractive index of the sensing fiber surface gradually becomes larger. Taking the logarithm of the glyphosate concentration as the abscissa and the interference characteristic peak difference ΔI as the ordinate, the linear relationship can be obtained through linear fitting.

[0101] It should be noted that in this application, the @ symbol represents connecting each layer and accumulating layer by layer.

[0102] It should be noted that the specific detection of the glyphosate is detected through the bonding action of the recognition substance. Since glyphosate inhibits the biosynthesis pathway existing in plants and certain microorganisms by inhibiting the enzyme, glyphosate can inhibit the bisphenolase activity of mushroom-extracted tyrosinase through a competitive mechanism. In the present invention, glyphosate specifically recognizes and captures the target glyphosate through the hydrogen bond and hydrophilic interaction of glyphosate with the external residues of the active site of tyrosinase.

[0103] Further, the recognition substance includes, but is not limited to, mushroom-derived tyrosinase.

[0104] The TYR solution is prepared as follows: Accurately weigh 3.0 mg of tyrosinase and dilute it with 10 mmol / L PBS solution at pH = 7 to prepare a tyrosinase solution with a final activity value of 350 U / mL, and store it refrigerated at 4°C for later use.

[0105] Further, the photothermal controlled-release green transformation is characterized by the photothermal effect excited by the second laser:

[0106] When the 808 nm laser is turned on at a power of 140 mW, the sensing optical fiber self-heats to 45°C in a short time. The low-melting-point AG film softens and partially melts under heating, resulting in the release of GOX originally encapsulated in the AG gel. GOX catalyzes the redox reaction of glyphosate through an enzymatic reaction, breaking the C-P bond of glyphosate to generate low-toxicity and simple small-molecule metabolites such as carbamic acid and phosphoric acid. These products are relatively close to the substances in the natural environment and usually do not cause further pollution to the environment. In addition, the metabolites can be further metabolized by microorganisms in the natural environment and will not accumulate for a long time. From the nature of the products, this method is an environmentally friendly green transformation process.

[0107] Finally, it should be noted that the above embodiments are only used for exemplifying and illustrating the present invention, and are not intended to limit the present invention to the scope of the described embodiments. In addition, those skilled in the art can understand that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope claimed by the present invention.

Claims

1. A dual-mode optical fiber sensor, characterized in that: The dual optical fiber sensor comprises a first sensor for realizing glyphosate detection through localized surface plasmon resonance and a second sensor for realizing glyphosate degradation through the photothermal effect of a nano material layer.

2. A dual-mode optical fiber sensor according to claim 1, characterized in that: The first sensor and the second sensor are both constructed based on the waist region of micro-nano optical fiber; The micro-nano optical fiber includes: a tapered transition region for exciting high-order modes and thus generating coupling between different modes, and a uniform waist region with significant evanescent field; The uniform waist region is provided with a structural guide layer, a noble metal layer and a nano material layer in sequence; The structural guide layer uses polydopamine (PDA) to coat the surface of the micro-nano optical fiber, providing stable chemical bonding for subsequent cumulative layers; The noble metal layer is composed of silver nanoparticles AgNPs with a thickness of 40nm-60nm and is solidified on the surface of the structural guide layer; The nanomaterial layer is composed of PDA@AgNPs, has a high specific surface area and abundant surface active sites, and is used to enhance the molecular binding stability and detection sensitivity.

3. A dual-mode optical fiber sensor according to claim 2, characterized in that: The active site of the nanomaterial layer of the first sensor further binds to tyrosinase TYR for specific binding to glyphosate molecules; wherein, the first sensor measures the glyphosate concentration by monitoring the change in the peak wavelength of the interference spectrum: under the action of the first laser input by the broadband light source, localized surface plasmon resonance is generated and the molecular binding signal is enhanced; glyphosate inhibits the enzymatic reaction of TYR, causing the interference spectrum peak in the optical fiber waist region to change.

4. A dual-mode optical fiber sensor according to claim 2, characterized in that: The nanomaterial layer of the second sensor is further assembled with glyphosate oxidoreductase GOX and agarose AG layer; under the action of a pump light source with a wavelength of 808nm, a photothermal effect of the nanomaterial is generated; wherein, the photothermal effect causes the AG layer to disintegrate, releasing GOX to catalyze the degradation of glyphosate; glyphosate is catalytically degraded into aminomethylphosphonic acid and glyoxylic acid, completing the green transformation of the polluted liquid.

5. A dual-mode optical fiber sensor according to claim 2, characterized in that: The structure guide layer, the noble metal layer and the nano material layer are prepared according to the following steps: Structural guiding layer: using ethanol as solvent, dissolving an appropriate amount of dopamine in ethanol, adjusting the pH to strong alkalinity with sodium hydroxide, the color of the solution gradually changes from colorless to dark black, indicating the generation of PDA, and dialyzing after stirring, and freeze-drying to obtain PDA powder; dispersing the PDA powder in an appropriate amount of deionized water to obtain a dopamine solution; then immersing the uniform waist area of ​​the prepared sensing optical fiber in the freshly prepared dopamine solution, reacting for an appropriate time, and obtaining a PDA-coated sensing optical fiber; Noble metal layer: Dissolve 0.34g ascorbic acid in 100ml deionized water, take 1mL to beaker A, dissolve 0.25g sodium citrate in 10mL deionized water, take 1mL to beaker A, add 32mL deionized water to beaker A, stir to fully dissolve, add 0.2m sodium citrate to adjust the pH value between 7.0-8.0, stir magnetically at 900 rpm, heat in a water bath at 30 degrees Celsius, gradually increase the temperature, add 0.32mL 0.1m AgNO3 solution, keep the reaction for 20min, take out the reaction solution, cool it, place it in a centrifuge and wash it repeatedly to obtain an AgNPs suspension, then immerse the uniform waist area of ​​the prepared sensing optical fiber in the freshly prepared AgNPs suspension, react for an appropriate time, and obtain a noble metal-coated sensing optical fiber; Nanomaterial layer: The sensing optical fiber coated with PDA@AgNPs is immersed in a TYR solution or a reductase solution to obtain a sensing optical fiber coated with a nanomaterial layer.

6. A dual-mode optical fiber sensor according to claim 2, characterized in that: The uniform waist diameter of the first sensor and the second sensor is 1-3 μm.

7. A glyphosate content determination and photothermal controlled release green conversion system, characterized in that: The system comprises a dual-mode optical fiber sensor as described in any one of claims 1 to 6, and a pump light source, a first coupler, a first pipeline, a first reaction pool, a second pipeline, a second coupler, a spectrometer, a broadband light source, an optical switch, a third pipeline, a fourth pipeline, a liquid storage tank, and a second reaction pool; Wherein, the optical transmission system includes the broadband light source, an optical switch, a first coupler and a second coupler, a first sensor, a second sensor, and a spectrometer; The output light signal of the pump light source is fed into the first sensor through the first coupler. The first sensor detects the glyphosate content. The generated light signal is gathered through the second coupler and transmitted to the spectrometer to complete the collection of the content detection signal. Another optical signal of the optical switch is input into the second sensor, and the second sensor receives the photothermal signal and transmits the optical change signal generated during the degradation process to the spectrometer through the second coupler to realize the collection of glyphosate degradation signals; Finally, the optical path completed the closed-loop transmission of glyphosate content detection and degradation signal collection; Wherein, the liquid flow system includes a liquid storage tank, a first reaction tank, a second reaction tank, a first pipeline, a second pipeline, a third pipeline and a fourth pipeline; The left side of the liquid storage tank stores glyphosate-contaminated liquid, which is poured into the first reaction tank through the first pipeline; the glyphosate solution in the first reaction tank is detected by the first sensor and then flows into the right side of the liquid storage tank as a recovery liquid; The recovered liquid is input into the second reaction tank through the fourth pipeline. In the second reaction tank, the glyphosate is degraded by the photothermal effect generated by the pump light source and the second sensor to generate a degradation liquid. The degradation liquid flows back to the left side of the liquid storage tank through the third pipeline, completing the degradation cycle of the polluted liquid. The liquid flow system realizes glyphosate detection through the first reaction tank and realizes photothermal degradation of glyphosate through the second reaction tank, ultimately completing the detection and green degradation transformation of glyphosate-contaminated liquid.

8. A method for determination of glyphosate content and photothermal controlled release green conversion, characterized in that: The method is performed based on the system according to claim 7, and comprises the following steps: Step 1: placing a dual-mode optical fiber sensor in a reaction pool made of epoxy resin and fixing it by UV glue and ultraviolet lamp irradiation; inputting a first laser into the tapered micro-nano optical fiber interferometer to generate evanescent waves and interference, monitoring the interference peak wavelength of the interference light, and when the interference peak wavelength changes, it is determined that glyphosate exists in the test system, and then proceeding to step 2, otherwise, glyphosate does not exist; Step 2: Switch the laser light source and input a second laser into the tapered micro-nano fiber interferometer to stimulate the photothermal effect of the nanomaterial layer for photothermal controlled release.

9. A method for determining glyphosate content and photothermal controlled release green conversion according to claim 8, characterized in that: The method includes establishing a linear relationship between glyphosate concentration and the change in interference peak wavelength; establishing a linear relationship between photothermal effect and glyphosate degradation conversion rate, and evaluating green conversion results; Injecting glyphosate contaminated liquid of different concentrations into the first reaction pool, inputting the first laser into the first sensor to generate evanescent waves and interference, monitoring the interference peak wavelength of the interference light, and establishing a linear regression equation between the glyphosate concentration and the change in the interference peak wavelength; The glyphosate-contaminated liquid is injected into the second reaction tank, the second laser is input to the second sensor to generate a photothermal effect, the relationship between the photothermal effect and the glyphosate degradation conversion rate is established, the first laser is input to generate evanescent waves and interference, the interference peak wavelength change of the interference light is monitored, and the interference peak is substituted into the linear regression equation to determine the glyphosate content after degradation.

10. A method for determining glyphosate content and photothermal controlled release green conversion according to claim 9, characterized in that: The light source of the first laser is a broadband light source with a wavelength of 1250-1650 nm; the light source of the second laser is a pump light source with a wavelength of 808 nm and a power of 40-160 mW.

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