Biological-nano composite dissolved oxygen sensor, preparation method thereof, dissolved oxygen detection system and method

Abstract

The invention discloses a biological-nano composite dissolved oxygen sensor, a preparation method thereof, and a dissolved oxygen detection system and method.The biological-nano composite dissolved oxygen sensor comprises silicon dioxide nanoparticles, the outer walls of the silicon dioxide nanoparticles are of a porous structure, and oxygen-sensitive protein is adsorbed in through holes in the outer walls of the silicon dioxide nanoparticles; a donor dye CY3 and an acceptor dye CY5 are loaded on the outer wall of the silicon dioxide nanoparticle, a hydrophilic anti-biological-pollution coating is arranged on the outer side of the silicon dioxide nanoparticle, the donor dye CY3, the acceptor dye CY5, the silicon dioxide nanoparticle and the oxygen-sensitive protein are all wrapped in the hydrophilic anti-biological-pollution coating, and the hydrophilic anti-biological-pollution coating is coated with the donor dye CY3, the acceptor dye CY5, the silicon dioxide nanoparticle and the oxygen-sensitive protein. The sensor, the detection system and the detection method can realize real-time, high-sensitivity, high-precision and low-cost detection of the dissolved oxygen of the water vapor system of the thermal equipment.

Description

Technical Field

[0001] This invention belongs to the field of water quality detection and sensing technology, and relates to a bio-nano composite dissolved oxygen sensor, its preparation method, and a dissolved oxygen detection system and method. Background Technology

[0002] The main hazard of dissolved oxygen in steam-water systems in boiler systems is corrosion. When water containing dissolved oxygen enters the boiler, most of the oxygen flashes into the steam, causing specific pitting corrosion at the waterline of the steam drum and the space where feedwater enters the steam drum. Feedwater pipes and economizer inlets are particularly susceptible to dissolved oxygen corrosion. Dissolved oxygen corrosion intensifies with increasing feedwater velocity and boiler heat load. Furthermore, corrosion products enter the boiler interior, adhering to or depositing on the inner walls of pipes and heating surfaces, forming insoluble iron scale. This severely reduces heat transfer efficiency and can cause pitting on the inner walls of pipes, even leading to boiler accidents. Boiler inspections have revealed a significant annual damage to boiler feedwater pipes, economizers, and other auxiliary equipment due to oxygen corrosion, resulting in substantial economic losses for enterprises and the nation. Statistics show that oxygen corrosion has shortened the average lifespan of industrial boilers in my country by one-third. Therefore, GB / T 12145-2016 sets strict regulations for dissolved oxygen levels in steam-water systems (condensate, deaerator inlet / outlet, feedwater, and steam, etc.).

[0003] Methods for detecting dissolved oxygen in water mainly include iodometric titration, fluorescence quenching, and electrochemical methods. Currently, the national standard method for dissolved oxygen detection is iodometric titration. However, this method has drawbacks such as cumbersome chemical measurement operations, long detection time, low resolution, and inability to meet the requirements for trace and rapid dissolved oxygen detection. For the measurement of trace dissolved oxygen, fluorescence quenching can be used. This detection technology has high measurement accuracy, good linearity, and is less susceptible to external interference, making it a relatively advanced dissolved oxygen measurement method. However, it also has disadvantages such as difficulty in manufacturing the sensor membrane, the need for optical circuit design in the detection instrument, high precision requirements in processing, high manufacturing difficulty, and high cost. Currently, power systems mostly use electrochemical sensors (such as Clark electrodes) to measure the dissolved oxygen content of water vapor samples. This method has a slow response speed and requires regular replacement of the electrolyte and dissolved oxygen membrane, resulting in high procurement and maintenance costs. It is also easily affected by impurities in the water sample. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bio-nano composite dissolved oxygen sensor, its preparation method, dissolved oxygen detection system and method. The sensor, detection system and method can realize real-time, high-sensitivity, high-precision and low-cost detection of dissolved oxygen in the water vapor system of thermal equipment.

[0005] To achieve the above objectives, this invention discloses a bio-nano composite dissolved oxygen sensor, comprising silica nanoparticles. The outer wall of the silica nanoparticles has a porous structure, and oxygen-sensitive proteins are adsorbed within the pores on the outer wall of the silica nanoparticles. The outer wall of the silica nanoparticles is loaded with donor dye CY3 and acceptor dye CY5. A hydrophilic anti-biofouling coating is disposed on the outer side of the silica nanoparticles, wherein the donor dye CY3, acceptor dye CY5, silica nanoparticles, and oxygen-sensitive proteins are all encapsulated within the hydrophilic anti-biofouling coating.

[0006] Furthermore, the particle size of the silica nanoparticles is 60-150 nm.

[0007] Furthermore, the pore size of the through holes on the outer wall of the silica nanoparticles is 3-10 nm.

[0008] This invention discloses a method for preparing a bio-nanocomposite dissolved oxygen sensor, comprising the following steps: 1) Take silica nanoparticles; 2) Loading oxygen-sensitive proteins onto the silica nanoparticles; 3) The silica nanoparticles loaded with oxygen-sensitive protein were reacted with CY3-NHS ester and CY5-maleimide respectively, and then washed with PBS buffer solution to load the surface of the silica nanoparticles with donor dye CY3 and acceptor dye CY5. Then, 1% polyethylene glycol (PEG) was added and stirred at room temperature to form a hydrophilic anti-biofouling coating. 4) Centrifuge the reaction product obtained in step 3), and then suspend the solid component in a PBS buffer solution of bovine serum albumin at a preset concentration to obtain a suspension of the bio-nanocomposite dissolved oxygen sensor.

[0009] Furthermore, the concentration of the suspension for the bio-nanocomposite dissolved oxygen sensor is 1 mg / mL.

[0010] This invention discloses a dissolved oxygen detection system based on fluorescence resonance energy transfer, comprising a flow cell, a flow cell water sample inlet, a flow cell water sample outlet, an excitation light source module, and a dual-channel fluorescence spectroscopy detection system. A columnar oxygen-permeable membrane is disposed within the flow cell, forming a suspension channel inside the membrane. An internal water sample flow channel is formed between the outer side of the membrane and the inner wall of the flow cell. The water sample inlet and outlet are connected to the internal water sample flow channel. The suspension channel is filled with a bio-nano composite dissolved oxygen sensor suspension. Transparent quartz detection windows are provided at both ends of the suspension channel. The excitation light source module faces the transparent quartz detection window at one end of the suspension channel, and the dual-channel fluorescence spectroscopy detection system faces the transparent quartz detection window at the other end of the suspension channel.

[0011] This invention discloses a dissolved oxygen detection method based on fluorescence resonance energy transfer, comprising the following steps: The water sample enters the flow cell through the water sample inlet. After the water sample fills the flow cell's internal flow channel, it is discharged from the flow cell through the water sample outlet. Dissolved oxygen in the water sample enters the suspension of the bio-nanocomposite dissolved oxygen sensor through the oxygen-permeable membrane and binds to the oxygen-sensitive protein. The excitation light source module generates an excitation light source, which illuminates the suspension of the bio-nano composite dissolved oxygen sensor through a transparent quartz detection window; The dual-channel fluorescence spectroscopy detection system detects the fluorescence intensity of two channels through a transparent quartz detection window at wavelengths of 570 nm and 670 nm, and calculates the fluorescence intensity ratio I. 570 / I 670 ; Because dissolved oxygen in the water sample binds to the oxygen-sensitive protein in the bio-nanocomposite dissolved oxygen sensor suspension, the protein conformation changes, altering the distance between the donor dye CY3 and the acceptor dye CY5. When the distance between the donor dye CY3 and the acceptor dye CY5 is greater, the fluorescence signal corresponding to CY3 is enhanced. 570 Increased fluorescence signal corresponds to a decrease in fluorescence intensity when the donor dye CY3 and the acceptor dye CY5 are closer together. 670 Increase, therefore through I 570 / I 670 The calculation results reflect the dissolved oxygen (DO) content in the water sample.

[0012] Furthermore, according to DO = k×(I 570 / I 670 The dissolved oxygen content (DO) is calculated using the fitting formula of () + b.

[0013] Furthermore, the excitation light source module generates a 470nm excitation light source.

[0014] Furthermore, the detection range for dissolved oxygen content is 0~20 mg / L.

[0015] The present invention has the following beneficial effects: The bio-nanocomposite dissolved oxygen sensor, its preparation method, and dissolved oxygen detection system and method described in this invention utilize the specificity of oxygen-sensitive proteins binding to oxygen molecules, causing a change in the distance between the donor dye CY3 and the acceptor dye CY5 loaded on the surface of the bio-nanocomposite dissolved oxygen probe. A dual-channel fluorescence detection system is used to detect the CY3 and CY5, achieving highly sensitive detection of dissolved oxygen. The FRET signal ratio improves the stability and accuracy of the detection. No chemical reagents are required during the measurement process. The bio-nano probe provided by this invention can be recycled through centrifugation, making the equipment both environmentally friendly and economical. Attached Figure Description

[0016] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a structural diagram of the sensor in this invention; Figure 2 This is a system structure diagram of the present invention.

[0017] Among them, 1 is the water sample inlet of the flow cell, 2 is the water sample outlet of the flow cell, 3 is the water sample flow channel inside the flow cell, 4 is the oxygen-permeable membrane, 5 is the biological-nano composite dissolved oxygen sensor suspension, 6 is the transparent quartz detection window, 7 is the excitation light source module, 8 is the dual-channel fluorescence spectroscopy detection system, 1-1 is the silica nanoparticle, 1-2 is the oxygen-sensitive protein, 1-3 is the donor dye CY3, 1-4 is the acceptor dye CY5, and 1-5 is the hydrophilic anti-biofouling coating. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0020] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0021] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0022] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0023] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0026] Example 1 The bio-nanocomposite dissolved oxygen sensor of the present invention includes silica nanoparticles 1-1, the outer wall of the silica nanoparticles 1-1 is a porous structure, wherein the particle size of the silica nanoparticles 1-1 is 60-150nm, and the pore size of the through holes on the outer wall of the silica nanoparticles 1-1 is 3-10nm. The silica nanoparticles 1-1 have oxygen-sensitive proteins 1-2 adsorbed in the pores on their outer walls. The silica nanoparticles 1-1 are loaded with donor dye CY31-3 and acceptor dye CY51-4 on their outer walls. A hydrophilic anti-biofouling coating 1-5 is provided on the outer side of the silica nanoparticles 1-1, wherein the donor dye CY31-3, the acceptor dye CY51-4, the silica nanoparticles 1-1, and the oxygen-sensitive proteins 1-2 are all encapsulated within the hydrophilic anti-biofouling coating 1-5.

[0027] Example 2 This invention discloses a method for preparing a bio-nanocomposite dissolved oxygen sensor. The bio-nanocomposite dissolved oxygen sensor includes silica nanoparticles 1-1, the outer wall of which has a porous structure. Oxygen-sensitive proteins 1-2 are adsorbed within the pores on the outer wall of the silica nanoparticles 1-1. The outer wall of the silica nanoparticles 1-1 is loaded with donor dye CY31-3 and acceptor dye CY51-4. A hydrophilic anti-biofouling coating 1-5 is disposed on the outer side of the silica nanoparticles 1-1, wherein the donor dye CY31-3, acceptor dye CY51-4, silica nanoparticles 1-1, and oxygen-sensitive proteins 1-2 are all encapsulated within the hydrophilic anti-biofouling coating 1-5.

[0028] Specifically, the preparation method of the bio-nanocomposite dissolved oxygen sensor includes the following steps: 1) The carrier is silica nanoparticles 1-1 with a porous surface structure. The particle size of silica nanoparticles 1-1 is 60~150nm, and the pore size of the porous surface structure is 3~10nm. 2) Loaded with oxygen-sensitive protein 1-2; Special microorganisms and bacteria contain oxygen-sensitive proteins 1-2. For example, oxygen-binding heme protein can be extracted from phosphorescent bacteria, and oxygen-sensitive proteins 1-2 can be expressed in processed Escherichia coli. Taking the oxygen-binding heme protein extract as an example, this invention prepares a 1.0 mg / mL oxygen-binding heme protein solution and purifies the oxygen-binding heme protein solution by Ni-NTA affinity chromatography column. Then, silica nanoparticles 1-1 are placed in the purified oxygen-binding heme protein solution, wherein 100 mg of silica nanoparticles 1-1 are placed in every 10 mL of oxygen-sensitive protein solution and placed in 10 mL of PBS buffer solution. The solution is then incubated at 4-5 °C for more than 12 hours with shaking in a constant temperature incubator, so that oxygen-sensitive proteins 1-2 are adsorbed in the pores on the outer wall of silica nanoparticles 1-1. 3) Loaded with donor dye CY31-3 and acceptor dye CY51-4; The silica nanoparticles 1-1 loaded with oxygen-sensitive protein 1-2 were reacted with CY3-NHS ester and CY5-maleimide, respectively. After washing with PBS buffer solution, the surface of the silica nanoparticles 1-1 was loaded with donor dye CY31-3 and acceptor dye CY51-4. Then, 1% polyethylene glycol (PEG) was added and stirred at room temperature for 4 hours to form a hydrophilic anti-biofouling coating 1-5. 4) The above reactants were centrifuged, and the resulting solid components were suspended in a PBS buffer solution of bovine serum albumin at a preset concentration to obtain a suspension of the bio-nanocomposite dissolved oxygen sensor. The concentration of the suspension was 1 mg / mL.

[0029] Example 3 The dissolved oxygen detection system based on fluorescence resonance energy transfer of the present invention includes a flow cell, in which a columnar oxygen-permeable membrane 4 is disposed. A suspension channel is formed inside the oxygen-permeable membrane 4. A water sample flow channel 3 is formed between the outer side of the oxygen-permeable membrane 4 and the inner wall of the flow cell. The water sample inlet 1 and the water sample outlet 2 of the flow cell are connected to the water sample flow channel 3 inside the flow cell. The suspension channel is filled with a bio-nano composite dissolved oxygen sensor suspension 5. Transparent quartz detection windows 6 are provided at both ends of the suspension channel. An excitation light source module 7 is positioned opposite the transparent quartz detection window 6 at one end of the suspension channel. A dual-channel fluorescence spectroscopy detection system 8 is positioned opposite the transparent quartz detection window 6 at the other end of the suspension channel.

[0030] Example 4 This embodiment discloses a dissolved oxygen detection method based on fluorescence resonance energy transfer (FRET), implemented using a FRET-based dissolved oxygen detection system. The FRET-based dissolved oxygen detection system includes a flow cell containing a columnar oxygen-permeable membrane 4. A suspension channel is formed inside the oxygen-permeable membrane 4. An internal water sample flow channel 3 is formed between the outer side of the oxygen-permeable membrane 4 and the inner wall of the flow cell. The water sample inlet 1 and outlet 2 of the flow cell are connected to the internal water sample flow channel 3. The suspension channel is filled with a bio-nano composite dissolved oxygen sensor suspension 5. Transparent quartz detection windows 6 are provided at both ends of the suspension channel. An excitation light source module 7 faces the transparent quartz detection window 6 at one end of the suspension channel, and a dual-channel fluorescence spectroscopy detection system 8 faces the transparent quartz detection window 6 at the other end of the suspension channel.

[0031] Specifically, the dissolved oxygen detection method based on fluorescence resonance energy transfer includes the following steps: The water sample enters the flow cell through the water sample inlet 1. After the water sample fills the water sample flow channel 3 inside the flow cell, it is discharged from the flow cell through the water sample outlet 2. Dissolved oxygen in the water sample enters the biological-nano composite dissolved oxygen sensor suspension 5 through oxygen-permeable membrane 4 and binds to oxygen-sensitive protein 1-2. Under hypoxic conditions, oxygen-sensitive protein 1-2 can emit strong light with luciferase, and under aerobic conditions, fluorescence is quenched due to conformational changes. The excitation light source module 7 generates a 470nm excitation light source, which irradiates the biological-nano composite dissolved oxygen sensor suspension 5 through the transparent quartz detection window 6. The dual-channel fluorescence spectroscopy detection system 8 detects the fluorescence intensity of two channels through a transparent quartz detection window 6, with detection wavelengths of 570 nm and 670 nm, and calculates the fluorescence intensity ratio I. 570 / I 670 ; Because dissolved oxygen in the water sample binds to oxygen-sensitive proteins 1-2 in the bio-nanocomposite dissolved oxygen sensor suspension 5, a conformational change occurs, altering the distance between the donor dye CY31-3 and the acceptor dye CY51-4. When the distance between the donor dye CY31-3 and the acceptor dye CY51-4 is greater, the fluorescence signal corresponding to CY3 is enhanced. 570 Increase; conversely, when the donor dye CY31-3 and the acceptor dye CY51-4 are closer together, the fluorescence signal corresponding to the acceptor dye CY51-4 is enhanced. 670 Increase, therefore can be achieved through I 570 / I 670 The calculation result reflects the dissolved oxygen content in the water sample, according to DO = k × (I 570 / I 670The dissolved oxygen content (DO) is calculated using the fitting formula of () + b.

[0032] The detection system has a detection range of 0~20 mg / L and a detection limit of 0.5 μg / L, and is suitable for online accurate measurement of dissolved oxygen content in the water-steam system of thermal equipment.

[0033] This invention utilizes the specificity of oxygen-sensitive proteins 1-2 binding to oxygen molecules, avoiding the influence of other interfering gases on the measurement results. The FRET signal ratio improves the stability and accuracy of the detection. The measurement process does not require the addition of chemical reagents. The bio-nano probe provided by this invention can be recycled through centrifugation, and the equipment is environmentally friendly and economical.

[0034] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0035] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0036] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A bio-nanocomposite dissolved oxygen sensor, characterized in that, The invention includes silica nanoparticles (1-1), the outer wall of which has a porous structure. Oxygen-sensitive protein (1-2) is adsorbed in the pores on the outer wall of the silica nanoparticles (1-1). The outer wall of the silica nanoparticles (1-1) is loaded with donor dye CY3 (1-3) and acceptor dye CY5 (1-4). A hydrophilic anti-biofouling coating (1-5) is provided on the outside of the silica nanoparticles (1-1). The donor dye CY3 (1-3), the acceptor dye CY5 (1-4), the silica nanoparticles (1-1), and the oxygen-sensitive protein (1-2) are all encapsulated in the hydrophilic anti-biofouling coating (1-5).

2. The bio-nanocomposite dissolved oxygen sensor according to claim 1, characterized in that, The silica nanoparticles (1-1) have a particle size of 60-150 nm.

3. The bio-nanocomposite dissolved oxygen sensor according to claim 1, characterized in that, The pore size of the through holes on the outer wall of the silica nanoparticles (1-1) is 3-10 nm.

4. A method for preparing a bio-nanocomposite dissolved oxygen sensor, characterized in that, Includes the following steps: 1) Take silica nanoparticles (1-1); 2) Load oxygen-sensitive protein (1-2) onto the silica nanoparticles (1-1); 3) The silica nanoparticles (1-1) loaded with oxygen-sensitive protein (1-2) were reacted with CY3-NHS ester and CY5-maleimide respectively, and then washed with PBS buffer solution to load the surface of silica nanoparticles (1-1) with donor dye CY3 (1-3) and acceptor dye CY5 (1-4). Then, 1% polyethylene glycol was added and stirred at room temperature to form a hydrophilic anti-biofouling coating (1-5). 4) Centrifuge the reaction product obtained in step 3), and then suspend the solid component in a PBS buffer solution of bovine serum albumin at a preset concentration to obtain a suspension of the bio-nanocomposite dissolved oxygen sensor.

5. The method for preparing the bio-nanocomposite dissolved oxygen sensor according to claim 4, characterized in that, The concentration of the suspension for the bio-nanocomposite dissolved oxygen sensor is 1 mg / mL.

6. A dissolved oxygen detection system based on fluorescence resonance energy transfer, characterized in that, The system includes a flow cell, a flow cell water sample inlet (1), a flow cell water sample outlet (2), an excitation light source module (7), and a dual-channel fluorescence spectroscopy detection system (8). A columnar oxygen-permeable membrane (4) is provided in the flow cell. A suspension channel is formed inside the oxygen-permeable membrane (4). A water sample flow channel (3) is formed between the outer side of the oxygen-permeable membrane (4) and the inner wall of the flow cell. The water sample inlet (1) and the water sample outlet (2) of the flow cell are connected to the water sample flow channel (3) inside the flow cell. The suspension channel is filled with a biological-nano composite dissolved oxygen sensor suspension (5). Transparent quartz detection windows (6) are provided at both ends of the suspension channel. The excitation light source module (7) is facing the transparent quartz detection window (6) at one end of the suspension channel, and the dual-channel fluorescence spectroscopy detection system (8) is facing the transparent quartz detection window (6) at the other end of the suspension channel.

7. A dissolved oxygen detection method based on fluorescence resonance energy transfer, characterized in that, The dissolved oxygen detection system based on fluorescence resonance energy transfer as described in claim 6 includes the following steps: The water sample enters the flow pool through the water sample inlet (1). After the water sample fills the water sample flow channel (3) inside the flow pool, it is discharged from the flow pool through the water sample outlet (2). Dissolved oxygen in the water sample enters the bio-nano composite dissolved oxygen sensor suspension (5) through the oxygen-permeable membrane (4) and binds to oxygen-sensitive proteins (1-2); The excitation light source module (7) generates an excitation light source, which irradiates the biological-nano composite dissolved oxygen sensor suspension (5) through the transparent quartz detection window (6). The dual-channel fluorescence spectroscopy detection system (8) detects the fluorescence intensity of two channels through a transparent quartz detection window (6), with detection wavelengths of 570 nm and 670 nm, respectively, and calculates the fluorescence intensity ratio I. 570 / I 670 ; Because dissolved oxygen in the water sample binds to oxygen-sensitive proteins (1-2) in the bio-nano composite dissolved oxygen sensor suspension (5), the protein conformation changes, and the distance between the donor dye CY3 (1-3) and the acceptor dye CY5 (1-4) changes. When the distance between the donor dye CY3 (1-3) and the acceptor dye CY5 (1-4) is greater, the fluorescence signal corresponding to the donor dye CY3 (1-3) is enhanced. 570 Conversely, when the donor dye CY3 (1-3) and the acceptor dye CY5 (1-4) are closer together, the fluorescence signal corresponding to the acceptor dye CY5 (1-4) is enhanced. 670 Increase, therefore through I 570 / I 670 The calculation results reflect the dissolved oxygen (DO) content in the water sample.

8. The dissolved oxygen detection method based on fluorescence resonance energy transfer according to claim 7, characterized in that, According to DO = k×(I) 570 / I 670 The dissolved oxygen content (DO) is calculated using the fitting formula of () + b.

9. The dissolved oxygen detection method based on fluorescence resonance energy transfer according to claim 7, characterized in that, Excitation light source module 7 generates a 470nm excitation light source.

10. The dissolved oxygen detection method based on fluorescence resonance energy transfer according to claim 7, characterized in that, The detection range for dissolved oxygen content is 0~20 mg / L.

Images