Portable detection device and detection method for detecting microcystic toxins based on bismuth oxybromide doped biomass carbon

Abstract

The invention discloses a portable detection device and a detection method for detecting microcystic toxins based on bismuth oxybromide doped biomass carbon, and belongs to the field of photoelectrochemical detection devices. The prepared BiOBr-coated BC nano composite material is used as a working electrode and is applied to a detection device, and the detection device further comprises a control system and a detection system. The detection system is fixed in the detection system shell, and the control system is fixed in the control system shell. Wherein the control system controls the LED lamp to emit exciting light to irradiate the working electrode, and the nano material in the detection system enters an excited state after receiving light to generate current. After a detection target object is added, separation of hole electron pairs can be influenced, so that the change of current is influenced. The concentration of the detected object is reflected by detecting the current change after the target objects with different concentrations are added. The device provided by the invention can realize detection of weak current signals, and meanwhile, compact and small equipment provides a scheme for portable detection.

Description

TECHNICAL FIELD

[0001] The application relates to the field of photoelectrochemical detection, and particularly relates to a portable detection device and a detection method for detecting microcystins based on bismuth oxybromide doped biomass carbon. BACKGROUND

[0002] Microcystins (MCs) are a class of cyclic peptide toxins produced by freshwater cyanobacteria, which have strong hepatotoxicity, neurotoxicity and carcinogenicity, and pose a serious threat to aquatic ecosystems and human health. Among them, microcystin-LR (MC-LR) is the most common and toxic variant. MC-LR has high chemical stability and heat resistance in water, can accumulate in aquatic organisms and be transmitted through the food chain, and ultimately endanger human health. The World Health Organization (WHO) stipulates that the maximum allowable concentration of MC-LR in drinking water is 1 μg / L. At present, the traditional MC-LR detection methods mainly include high performance liquid chromatography (HPLC) method, liquid chromatography-mass spectrometry (LC-MS) method, enzyme-linked immunosorbent assay (ELISA) method, etc. Although these methods have high sensitivity and accuracy, they have limitations such as expensive instruments, complex operation, long detection time, and tedious sample pretreatment. Therefore, it is urgent to develop a sensitive, rapid, and easy-to-promote analysis method for analyzing MC-LR suitable for on-site detection.

[0003] Photoelectrochemical sensors use light as the excitation source and the detection signal is an electrical signal. The two different energy forms achieve the separation of excitation light source and detection device and do not affect each other, thus combining the advantages of optical and electrochemical sensors: easy to realize integration and miniaturization and low background signal, high sensitivity.

[0004] With the continuous progress of science and technology, nanomaterials have been widely used in sensors and detection devices due to their unique physical and chemical properties. Nanomaterials have a large specific surface area, excellent electrical conductivity, optical properties and catalytic activity, which make them exhibit excellent performance in environmental monitoring, biological detection and food safety.

[0005] Therefore, it is particularly important to develop a portable, sensitive and easy-to-operate detection device. The present application aims to provide a novel portable detection device based on nanomaterials for detecting microcystins. By optimizing the design and combination of nanomaterials, the detection sensitivity and selectivity are improved, so as to realize rapid and accurate detection of target substances and meet the needs of on-site applications. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a preparation method of BiOBr doped biomass carbon nanocomposite (BiOBr@BC), which uses shrimp shells as raw materials to prepare BiOBr@BC, and the use of BiOBr@BC prepared by the method in detecting MC-LR through a designed portable detection device.

[0007] The present application realizes the above technical object through the following technical means.

[0008] A preparation method of BiOBr@BC, comprising the following steps:

[0009] Step 1, preparing shrimp shell biomass carbon

[0010] The shrimp shells are cleaned and dried, then crushed by a crusher to obtain shrimp shell powder, and the shrimp shell powder is calcined in a tube furnace. The calcined product is soaked in a hydrochloric acid solution, and impurities are removed by stirring. After solid-liquid separation, the separated solid product is dried in an oven. Finally, the dried product is mechanically crushed in a ball mill, and the obtained black powder-shaped biomass carbon material is collected and marked as BC.

[0011] Step 2, preparing BiOBr@BC

[0012] A certain amount of bismuth nitrate pentahydrate is added to a glycol solution containing cetyltrimethylammonium bromide, and stirred to obtain a uniform dispersion A. The BC prepared in step 1 is added to the dispersion A, and after stirring, a mixture B is obtained. The mixture B is transferred to a high-pressure reaction kettle, the reaction temperature is set, and the constant temperature reaction is carried out. After the reaction is completed, the solid is collected by centrifugation, washing and drying in an oven to obtain a solid powder, which is marked as BiOBr@BC.

[0013] In the above scheme, in step 1, the tube furnace is set at a heating rate of 8℃ / min -1 , the holding temperature is 400℃, and the holding time is 2h; the ball mill grinding speed is 600r / min -1 , and the crushing time is 0.5h; the concentration of the hydrochloric acid solution is 5%, and the stirring time is 12h; the solid-liquid separation is realized by a vacuum pump; and the drying condition is 80℃ for 12h.

[0014] In step 2, the bismuth nitrate pentahydrate is mixed with the glycol solution containing cetyltrimethylammonium bromide for 0.5h; the reaction temperature of the mixed solution in the high-pressure reaction kettle is 140℃, and the reaction time is 12h; the washing condition is to use deionized water and ethanol at 50℃ for multiple times, so that the material after washing is neutral; and the drying condition is 50℃ for 12h.

[0015] A detection electrode is prepared by the BiOBr@BC prepared by the above method, and the preparation steps are as follows:

[0016] (A1) BiOBr@BC is dispersed in N,N-dimethylformamide to prepare a suspension;

[0017] (A2) 10-30 μL of the suspension in step (A1) is modified on an ITO electrode, and dried at room temperature to obtain a modified electrode, which is recorded as BiOBr@BC / ITO; 10-50 μL of an aptamer solution of MC-LR is drop-coated on the surface of the prepared BiOBr@BC / ITO electrode, and after incubation at room temperature for 4 h, it is washed with a buffer solution and ultrapure water, and dried at room temperature to obtain an aptamer / BiOBr@BC / ITO electrode, which is recorded as apt / BiOBr@BC / ITO;

[0018] (A3) 10-50 μL of MC-LR solution with different concentrations is drop-coated on the apt / BiOBr@BC / ITO electrode to obtain an MC-LR / apt / BiOBr@BC / ITO electrode.

[0019] (A4) A three-electrode detection system is established with the MC-LR / apt / BiOBr@BC / ITO electrode as a working electrode, a silver / silver chloride electrode as a reference electrode, and a platinum wire electrode as a counter electrode, and the concentration of MC-LR is detected.

[0020] In the above scheme, in step (A1), the concentration of BiOBr@BC is 2 mg mL -1 ;

[0021] In step (A2), the sequence of the MC-LR aptamer is: 5'-GGC GCC AAA CAG GAC CAC CAT GAC AAT TAC CCA TAC CAC CTC ATT ATG CCC CAT CTC CGC-3';

[0022] In step (A3), the concentration of MC-LR is 1×10 -2 -2×10 3 pM.

[0023] A portable microcystin detection device based on nanomaterials, comprising a detection electrode, a detection system and a control system; the detection system is arranged in a detection system shell, and the control system is arranged in a control system shell, wherein the control system provides the required light for the detection system to realize the chemical reaction of the sample; the control system is used to receive and feedback the current change of the detection system due to the chemical reaction, and the concentration of the sample detection substance microcystin is obtained according to the current change.

[0024] In the scheme, the detection system comprises a detection system shell, a reaction cell, a reaction cell cover, a detection electrode and an LED lamp; the detection system shell is divided into several areas; the detection system is installed in the detection system shell; the LED lamp is installed in the detection system shell; the control system is connected with the detection system through a hole formed on the control system shell; the detection electrode comprises an Ag / AgCl electrode as a reference electrode, a platinum wire electrode as a counter electrode and an MC-LR / apt / BiOBr@BC / ITO electrode as a working electrode; the reaction cell cover is provided with a mounting hole for mounting the reference electrode, the working electrode and the counter electrode; and the reaction cell cover is matched with an opening on the reaction cell.

[0025] In the scheme, the control system comprises a control system shell, a shell cover, a printed circuit board (PCB board), a fixing plate and a lithium battery; the lithium battery supplies power for the operation of the entire device; the fixing plate is used for fixing the lithium battery and the PCB board; the printed circuit board is electrically connected with the LED lamp of the detection system; and the PCB board is provided with a WiFi unit for data collection and transmission.

[0026] In the scheme, the control system controls the LED light emission to provide the required light for the detection system.

[0027] The present application has the following beneficial effects:

[0028] 1. The detection device designed in the present application can realize the detection of weak current signals, has a compact overall structure, is small and portable, and is suitable for carrying to the outdoor for detection. Compared with the sampling, transportation and detection of the traditional detection, the detection device greatly reduces the complexity of detection and the cost of detection.

[0029] 2. The photoelectrochemical detection device based on nanomaterials uses a composite nanomaterial composed of biomass carbon material made of agricultural waste and metal oxide nanomaterial to detect, and the photocatalytic performance of the composite nanomaterial is much greater than that of the single nanomaterial. Meanwhile, the natural biomolecular structure reserved in the biomass carbon skeleton provides an excellent biocompatible interface for the detection system. This technology path combining the high-value utilization of solid waste resources and nanoscale synergistic effect not only breaks through the performance bottleneck of traditional photoelectric materials, but also provides a new solution for the development of green analysis technology platform. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 XRD spectrum of BiOBr@BC nanocomposite material;

[0031] Figure 2 XPS spectrum of BiOBr@BC nanocomposite material;

[0032] Figure 3It is the photocurrent curve diagram of BiOBr@BC nano composite material under different conditions, wherein, curve a is the photocurrent of BiOBr@BC / ITO electrode, curve b is the photocurrent of apt / BiOBr@BC / ITO electrode, and curve c is the photocurrent of MC-LR / apt / BiOBr@BC / ITO electrode;

[0033] Figure 4 It is the photocurrent intensity change of apt / BiOBr@BC / ITO electrode under the condition that the concentration of MC-LR solution increases;

[0034] Figure 5 It is the portable detection device based on the nano composite material of the application;

[0035] Figure 6 It is the internal view of the control system shell involved in the application;

[0036] Figure 7 It is the control system shell cover view involved in the application;

[0037] Figure 8 It is the internal plan view of the control system shell involved in the application;

[0038] Figure 9 It is the control system assembly structure involved in the application;

[0039] Figure 10 It is the detection system shell involved in the application;

[0040] Figure 11 It is the detection device reaction pool assembly drawing involved in the application;

[0041] Figure 12 It is the internal view of the reaction pool cover involved in the application;

[0042] Figure 13 It is the reaction pool involved in the application;

[0043] Figure 14 It is the detection system three-electrode body assembly drawing involved in the application;

[0044] Figure 15 It is the detection device shell perspective view involved in the application.

[0045] Reference signs:

[0046] 1-control system; 2-detection system; 101-control system shell; 102 control system shell cover; 103- partition; 104-switch; 105-printed circuit board; 106-acrylic fixing plate; 107-electronic components; 108-lithium battery; 201-detection system shell; 202-reaction cell cover; 203-reaction cell; 204-platinum wire electrode; 205-silver / silver chloride electrode; 206-working electrode; 207-LED lamp. DETAILED DESCRIPTION

[0047] The application will be further described below in conjunction with the accompanying drawings and examples.

[0048] A preparation method of BiOBr@BC includes the following steps:

[0049] Step 1, preparation of shrimp shell biomass carbon

[0050] Take the washed and dried shrimp shells, crush them in a pulverizer to obtain shrimp shell powder, and then take the shrimp shell powder and place it in a tube furnace. Heat it to 400℃ at a heating rate of 8℃ / min and maintain the temperature for 2h. After the reaction is completed, immerse the product in a 5% hydrochloric acid solution and stir for 12h. After solid-liquid separation using a vacuum pump, transfer the collected solid product to an oven and dry it at 80℃ for 12h. Finally, mill the dried product in a ball mill at 600r / min for 30min, and collect the obtained black powder-shaped biomass carbon, which is denoted as BC. -1 Step 2, preparation of BiOBr@BC

[0051] Step 2, preparation of BiOBr@BC

[0052] Weigh a certain amount of bismuth nitrate pentahydrate and add it to a glycol solution containing cetyltrimethylammonium bromide, stir thoroughly for 30min to obtain a uniform dispersion A; then, add the BC obtained in step 1 to dispersion A and continue stirring for 1h to obtain a mixed solution B. Transfer the stirred mixed solution B to a 25mL polytetrafluoroethylene high-pressure reaction kettle and react at 140℃ for 12h. After the reaction kettle is naturally cooled to room temperature, remove the product. Wash the sample with deionized water and ethanol at 50℃ until it is neutral, and then transfer the product to an oven and dry it at 50℃ for 12h to obtain a BiOBr-doped biomass carbon composite nanomaterial, denoted as BiOBr@BC.

[0053] The prepared BiOBr@BC is used in a photoelectrochemical portable detection device to detect MC-LR, including the following steps:

[0054] (A1) Disperse BiOBr@BC in N,N-dimethylformamide to prepare a dispersion with a concentration of 2mg / mL -1

[0055] ​(A2) Take 10-30 μL of the dispersion liquid described in step (A1) to modify on the ITO electrode, and dry under the infrared lamp to obtain a modified electrode, which is recorded as BiOBr@BC / ITO; then drop 10-50 μL of the aptamer solution (3 μM) of MC-LR (the sequence of the aptamer of MC-LR is: 5'-GGC GCC AAA CAG GAC CAC CAT GAC AAT TAC CCA TAC CAC CTC ATT ATG CCC CAT CTC CGC-3'), and after incubation at room temperature for 4 h, wash off the excess aptamer with buffer solution and ultrapure water, and dry at room temperature to obtain the apt / BiOBr@BC / ITO electrode;

[0056] (A3) Take different concentrations of MC-LR solution to drop on the apt / BiOBr@BC / ITO electrode to obtain the MC-LR / apt / BiOBr@BC / ITO electrode. Take the MC-LR / apt / BiOBr@BC / ITO electrode as the working electrode, the silver / silver chloride electrode as the reference electrode, and the platinum wire (Pt) electrode as the counter electrode to construct a three-electrode system, detect the concentration of MC-LR, and the MC-LR / apt / BiOBr@BC / ITO electrode needs to be replaced after single measurement.

[0057] Figure 1The X-ray diffraction (XRD) pattern of the BiOBr@BC composite material prepared in Example 1 is shown. Phase analysis results indicate that BiOBr@BC consists of three phases: bismuth oxybromide (BiOBr), biochar, and silicon dioxide (SiO2). The diffraction peaks of the BiOBr phase appear at 10.9° (001), 24.9° (011), 29.7° (012), 32.6° (101), 32.9° (102), 39.4° (110), 46.4° (003), 48.2° (200), 50.8° (113), 54.1° (211), 57.0° (112), 68.9° (220), 72.2° (114), 79.3° (004), and 81.2° (214). All characteristic peaks are in good agreement with the standard powder diffraction card of BiOBr (PDF#01-073-2061), confirming its crystal structure. The broadened diffraction peaks of biomass-derived carbon appear at 26.7° and 44.8°, which can be attributed to its disordered graphitized structure (PDF#01-075-2078). The diffraction peaks of the silica phase are located at 20.8°, 35.1°, 37.8°, and 66.1°, corresponding to the characteristic peaks of the quartz phase (PDF#01-086-2237) and stishovite (PDF#01-074-3490), respectively. In summary, the XRD analysis results confirm the successful synthesis of the BiOBr@BC composite material, whose structure consists of a multiphase coexistence of BiOBr, biomass carbon, and silica. This multiphase structure helps to regulate the overall structural and functional properties of the material.

[0058] Figure 2 The X-ray photoelectron spectroscopy (XPS) analysis results of the BiOBr@BC nanocomposite prepared in Example 1 are presented. Full spectrum scan ( Figure 2 Figure a in the image confirms the presence of Bi, Br, C, N, and O elements in the material. Bi 4f spectrum ( Figure 2 (As shown in Figure b) The characteristic peaks at 159.1 eV and 164.4 eV are attributed to Bi 4f, respectively. 7 / 2 and Bi 4f 5 / 2 The chemical state of bismuth is consistent with that in BiOBr. Br 3d spectrum ( Figure 2 The peaks at 68.2 eV and 69.2 eV (as shown in Figure c) are respectively related to Br 3d 5 / 2 and Br 3d 3 / 2 Matching. C 1s spectrum ( Figure 2The d-plot (shown in the figure) shows peaks of 284.7 eV (CC / C=C), 285.9 eV (Co), 286.5 eV (Cn / Cp), and 288.3 eV (Cop), indicating the presence of carbon-based functional groups in BC. Nitrogen 1s spectrum ( Figure 2 As shown in the 1s spectrum, peaks appear at 399.4 eV (pyridine N), 402.5 eV (graphite N), and 405.9 eV (N oxide), indicating that nitrogen was successfully doped into the carbon layer. Figure 2 The figure (f) mainly contains lattice oxygen (Bi-O) at 529.8 eV, hydroxyl / ether oxygen (CO) at 531.2 eV, and carbonyl oxygen (C=O) at 533.1 eV, significantly demonstrating the interaction between the BiOBr lattice, surface hydroxyl groups, and oxygen species in the BC carbon layer. These results confirm the successful synthesis of BiOBr@BC nanocomposites and the strong interfacial interaction between BiOBr sheets and Bio-C.

[0059] Figure 3 The photocurrent signal changes are shown when the BiOBr@BC prepared in Example 1 is applied to a sensor. The BiOBr@BC modified electrode (curve a) exhibits a strong photocurrent response due to its efficient charge separation capability; while the apt / BiOBr@BC / ITO modified electrode (curve b), after combining with the aptamer, shows a significant enhancement in photocurrent. After drop-coating the prepared apt / BiOBr@BC / ITO electrode with MC-LR solution (curve c), the photocurrent further increases. This is mainly because the aptamer on the electrode can specifically recognize MC-LR, causing MC-LR and the aptamer to bind and detach from the material surface, thereby restoring the photocurrent of the sensor. Thus, a photoelectrochemical sensor for detecting MC-LR was successfully constructed.

[0060] Figure 4 The photocurrent intensity change of the apt / BiOBr@BC / ITO electrode prepared in Example 1 is shown with increasing MC-LR solution concentration. The MC-LR solution concentrations to be tested were 1×10⁻⁶. -2 pM, 5×10 -2 pM, 1×10 -1 pM, 5×10 -1 pM, 1pM, 10pM, 100pM, 1×10 3 pM. For example Figure 4 As shown in Figure A, the intensity of the photocurrent increases with increasing MC-LR solution concentration; as... Figure 4 As shown in Figure B, a standard curve was plotted using the logarithm (logC) of photocurrent intensity and different MC-LR solution concentrations, revealing that its optimal linear range was 1×10⁻⁶. -2 pM~1×103 pM, the minimum detection limit 3fM, thus the photoelectrochemical ligand sensor of the application can detect MC-LR sensitively.

[0061] A portable microcystin detection device based on bismuth oxybromide doped biomass carbon, as shown in the figure, comprising a control system 1 and a detection system 2; the control system 1 controls the LED lamp 207 in the detection system 2 to provide the required light for the detection system 2 to realize the electrochemical reaction of the sample; the control system 1 detects and obtains the change of the electrical signal in the detection system 2 in real time through electrical connection, and realizes data transmission through a wireless unit, and the control system 1 obtains the concentration of microcystin according to the change of the electrical signal. Figure 5 As shown in the figure, the control system 1 comprises a control system shell 101, a control system shell cover 102, a partition plate 103, a switch 104, a printed circuit board 105, an acrylic fixing plate 106, an electronic element 107 and a lithium battery 108, wherein the internal space of the control system shell 101 is divided into parallel grooves 1 and 2, and the space of the groove 2 is larger than that of the groove 1, the groove 1 and the groove 2 are separated by the partition plate 103, and the partition plate 103 is provided with a hole B, the printed circuit board 105 is electrically connected with the detection system 2 to receive and process the electrical signal from the detection system 2; the partition plate 103 is used to fix the printed circuit board 105 in the groove 2; the key switch 104 controls the start and stop of the whole control system 1, the switch 104 is stretched out through the hole A on the control system shell cover 102 to realize external key operation; the acrylic fixing plate 106 is used to fix the printed circuit board 105 and the lithium battery 108 at the bottom; the electronic element 107 is fixedly welded on the printed circuit board 105, and the electronic element is used to transmit and process data with the detection system 2; the lithium battery 108 supplies power for the whole control system 1.

[0062] Figures 6-9 As shown in the figure, the control system 1 comprises a control system shell 101, a control system shell cover 102, a partition plate 103, a switch 104, a printed circuit board 105, an acrylic fixing plate 106, an electronic element 107 and a lithium battery 108, wherein the internal space of the control system shell 101 is divided into parallel grooves 1 and 2, and the space of the groove 2 is larger than that of the groove 1, the groove 1 and the groove 2 are separated by the partition plate 103, and the partition plate 103 is provided with a hole B, the printed circuit board 105 is electrically connected with the detection system 2 to receive and process the electrical signal from the detection system 2; the partition plate 103 is used to fix the printed circuit board 105 in the groove 2; the key switch 104 controls the start and stop of the whole control system 1, the switch 104 is stretched out through the hole A on the control system shell cover 102 to realize external key operation; the acrylic fixing plate 106 is used to fix the printed circuit board 105 and the lithium battery 108 at the bottom; the electronic element 107 is fixedly welded on the printed circuit board 105, and the electronic element is used to transmit and process data with the detection system 2; the lithium battery 108 supplies power for the whole control system 1.

[0063] As shown in the figure, the control system 1 comprises a control system shell 101, a control system shell cover 102, a partition plate 103, a switch 104, a printed circuit board 105, an acrylic fixing plate 106, an electronic element 107 and a lithium battery 108, wherein the internal space of the control system shell 101 is divided into parallel grooves 1 and 2, and the space of the groove 2 is larger than that of the groove 1, the groove 1 and the groove 2 are separated by the partition plate 103, and the partition plate 103 is provided with a hole B, the printed circuit board 105 is electrically connected with the detection system 2 to receive and process the electrical signal from the detection system 2; the partition plate 103 is used to fix the printed circuit board 105 in the groove 2; the key switch 104 controls the start and stop of the whole control system 1, the switch 104 is stretched out through the hole A on the control system shell cover 102 to realize external key operation; the acrylic fixing plate 106 is used to fix the printed circuit board 105 and the lithium battery 108 at the bottom; the electronic element 107 is fixedly welded on the printed circuit board 105, and the electronic element is used to transmit and process data with the detection system 2; the lithium battery 108 supplies power for the whole control system 1. Figures 10-15

[0064] ​​The light emitted by the LED lamp 207 is transmitted through the reaction pool 203 and irradiated on the working electrode 206.

[0065] A portable detection device based on bismuth oxybromide doped biomass carbon comprises a control system 1 and a detection system 2.

[0066] The control system 1 comprises a control system shell 101, a control system shell cover 102, a partition plate 103, a switch 104, a printed circuit board 105, an acrylic fixing plate 106, electronic components 107 and a lithium battery 108; the control system 1 takes the control system shell 101 as the main body; the control system shell 101 is separated by the partition plate 103 into a groove 1 and a groove 2; the printed circuit board 105 is fixed in the groove 2 and is fixed by using the partition plate 103; the switch 104 is fixed on the printed circuit board 105 to realize the start and stop of the control system; the electronic components 107 are fixed on the printed circuit board 105; the acrylic fixing plate is used to connect and fix the printed circuit board 105 and the lithium battery 108; the control system shell cover 102 is provided with a hole A matched with the switch 104; the partition plate 103 is provided with a wiring hole B to realize the electrical connection of the printed circuit board 105 with the platinum wire electrode 204, the silver / silver chloride electrode 205, the working electrode 206 and the LED lamp 207; the groove 1 is used to place the electrical connection wire; the opening of the control system shell 101 is matched with the control system shell cover 102;

[0067] The detection system 2 comprises a detection system shell 201, a reaction pool cover 202, a reaction pool 203, a platinum wire electrode 204, a silver / silver chloride electrode 205, a working electrode 206 and an LED lamp 207; the detection system shell 201 is internally provided with a groove 3 and a groove 4; the silver / silver chloride electrode 205 is fixedly installed through an electrode installation hole a provided on the reaction pool cover 202; the working electrode 206 is fixedly installed through an electrode installation hole b provided on the reaction pool cover 202; the platinum wire electrode 204 is fixedly installed through an electrode installation hole c provided on the reaction pool cover 202; the reaction pool cover 202 is matched with the opening on the reaction pool 203; the reaction pool 203 is fixed in the groove 4 and can be pushed out of the detection system shell 201 through a push installation hole d provided on the detection system shell 201; the LED lamp 207 is fixed in the groove 3; the LED lamp is aligned with the working electrode 206 to provide a driving light source for the working electrode 206.

[0068] The whole control system shell 101, control system shell cover 102 and partition plate 103 are prepared by using 3D printing technology, meeting the requirements of compactness, portability and lightness; the control system shell 101 is separated into groove 1 and groove 2 by using the partition plate 103, the partition plate 103 is 20mm long and 10-20mm high; groove 2 is a rectangular hole with a cross section of 44mm*20mm, which realizes the function of fixing the printed circuit board 105 to the control system shell 101; a rectangular wiring hole B with a size of 6mm*2mm is opened on the partition plate 103, which is used for electrically connecting the control system 1 and the detection system 2; groove 1 is a rectangular hole with a cross section of 20mm*7mm, which is used for placing the electrically connected wire, and the electrically connected wire is connected with the electrode of the detection system 2 through the hole of the control system shell 101;

[0069] The control system shell cover 102 cooperates with the control system shell 101 to provide a closed environment for the control system 1; a rectangular hole A with a size of 5mm*4mm is opened on the control system shell cover 102, which is used for cooperating with the switch 104 to realize the start-stop work of the control system 1;

[0070] The detection system 2, the whole detection system shell 201 and the reaction pool cover 202 are prepared by using 3D printing technology and black material, meeting the darkroom requirement of the detection device; groove 3 and groove 4 are opened in the detection system shell; the cross section of groove 4 is a square hole with a side length of 12mm, and the depth is 45mm; the reaction pool 203 is a hollow cuboid with a cross section side length of 12mm and a height of 45mm, and the wall thickness is 1-3mm; the reaction pool 203 is fixed in cooperation with groove 4; the reaction pool cover 202 is a cuboid with a cross section side length of 16mm and a height of 8mm, and the inside is provided with electrode mounting hole c with a hole diameter of 0.1-0.5mm for fixing the platinum wire electrode 204, electrode mounting hole a with a hole diameter of 1-3mm for fixing the silver / silver chloride electrode 205, and electrode mounting hole b with a hole diameter of 2-4mm for fixing the working electrode 206; the reaction pool cover 202 cooperates with the opening of the reaction pool 203, and the three electrodes detect the target object in the reaction pool 203 to generate changes in electric signals; the bottom of the system shell 201 is also provided with a dismounting hole d for pushing out the reaction pool, facilitating the replacement of the detection object;

[0071] The LED lamp 207 is controlled by the control system 1 to provide a stable light source for the detection system 2; the LED lamp is fixed in groove 3 of the detection system shell 201 and is aligned with the working electrode 206, realizing the function of light driving; the control system 1 electrically connects the LED lamp and the detection system 2 by using the printed circuit board 105, realizes the collection, filtering, amplification and data processing of the electric signals from the detection system 2, and transmits the detection result data to a mobile device (such as a mobile phone) through wireless communication, ensuring the normal operation of the whole device.

[0072] The accompanying drawings Figure 5 ,Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 As shown in the figure, the control system shell 101 is 54mm long, 22mm wide and 17mm high; the control system shell 101 uses the partition plate 103 to separate the groove 1 and the groove 2, and the partition plate 103 is 20mm long and 16mm high; wherein the groove 2 is a rectangular through hole with a size of 44mm*20mm; the partition plate 103 is provided with a rectangular wiring hole B with a size of 6mm*2mm; wherein the groove 1 is a rectangular hole with a size of 20mm*7mm; the control system shell cover 102 is 54mm long, 22mm wide and 1mm thick; the control system shell cover 102 cooperates with the control system shell 101 to provide a sealed environment for the control system 1, and the volume block for cooperation is 44mm long, 20mm wide and 1mm thick; the control system shell cover 102 is provided with a rectangular through hole A with a size of 5mm*4mm for cooperating with the switch 104;

[0073] Combining with the attached Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 As shown in the figure, the detection system shell 201 is a cuboid structure with a size of 22mm long*16mm wide, and a groove 3 and a groove 4 are arranged inside. Among them, the groove 4 is a square hole with a side length of 12mm, and the depth reaches 45mm; the reaction pool 203 is a hollow cuboid with a side length of 12mm*height of 45mm, and the wall thickness is 1mm, which can be fixed with the groove 4. The opening of the reaction pool 203 is matched with the reaction pool cover 202, and the reaction pool cover 203 is a cuboid with a length of 16mm and a height of 8mm, and three electrode mounting holes are arranged inside: the mounting hole a is used for fixing the silver / silver chloride electrode 205, and the hole diameter is 1mm; the mounting hole b is used for fixing the working electrode 206, and the hole diameter is 2mm; the mounting hole c is used for fixing the platinum wire electrode 204, and the hole diameter is 0.2mm.

[0074] Combining with the attached Figure 14 As shown in the figure, the reaction pool cover 202 fixes the three-electrode system composed of the reference electrode (platinum wire electrode), the counter electrode (silver / silver chloride electrode) and the working electrode (BiOBr@BC / ITO). The control system 1 controls the LED lamp 207 to emit excitation light on the working electrode, and the nanomaterial on the working electrode enters the excited state after receiving light, generating current. After the detection target is added, it will affect the separation of the hole-electron pair of the nanomaterial, thereby affecting the change of the current. By detecting the current change after adding different concentrations of target, the concentration of the reaction detection object is detected.

[0075] Combining with the attached Figure 15 As shown in the figure, the bottom of the detection system shell 201 is also provided with a push-out hole d for pushing out the reaction pool, and the hole is a through hole with a hole diameter of 8mm.

[0076] The application also includes a microcystin detection method using the portable detection device for detecting microcystin based on bismuth oxybromide doped biomass carbon, which is realized according to the following steps:

[0077] S1, the switch 104 is pressed to start the detection device, and the LED lamp 207 in the groove 3 of the detection system 2 is controlled by the electronic element 107 of the control system 1 to emit excitation light, and the excitation light irradiates on the working electrode through the reaction pool 203;

[0078] S2, the nanomaterial on the working electrode enters an excited state after receiving the excitation light, and generates an electric current;

[0079] S3, the detection target in the reaction pool affects the separation of hole-electron pairs, thereby affecting the change of the electric current;

[0080] S4, the control system 1 receives the electric current signal in real time, and processes the concentration of the detection target according to the electric current change corresponding to different concentrations of the detection target.

[0081] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the description of the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0082] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0083] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, can also be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0084] The above series of detailed descriptions are only specific descriptions of the feasible embodiments of the present application, and are not intended to limit the protection scope of the present application. Any equivalent means or changes without departing from the technology of the present application shall be included in the protection scope of the present application.

Claims

1. A portable detection device for detecting microcystins based on bismuth oxybromide doped biomass carbon, characterized in that, The application relates to a microcystin detection device, which comprises a control system (1) in a control system shell (101) and a detection system (2) in a detection system shell (201), the control system (1) is used for controlling the LED lamp (207) in the detection system (2) to emit excitation light, and the control system (1) obtains the electric signal of the detection electrode in the detection system (2) in real time, processes the information according to the electric signal, and obtains the concentration of the microcystin.

2. The portable detection device for detecting microcystins based on BiOBr doped biomass carbon according to claim 1, characterized in that, The control system shell (101) is divided into parallel groove 1 and groove 2, and the space of the groove 2 is larger than that of the groove 1; the groove 1 and the groove 2 are separated by a partition plate (103), and a wiring hole B is arranged on the partition plate (103). The control system (1) comprises a switch (104), a printed circuit board (105), an acrylic fixing plate (106), an electronic element (107) and a lithium battery (108); the printed circuit board (105) is fixed in the groove 2 through the partition plate (103); the acrylic fixing plate (106) is used for fixing the printed circuit board (105) and the lithium battery (108) at the bottom; the electronic element (107) is fixedly welded on the printed circuit board (105), and the electronic element (107) is used for transmitting data and processing data with the detection system (2); and the lithium battery (108) is used for supplying power for the whole control system (1). The control system shell (101) and the control system shell cover (102) cooperatively provide a closed environment, the switch (104) is extended through a hole A on the control system shell cover (102), and external button operation is realized to control the start and stop of the whole detection device.

3. The portable detection device for detecting microcystins based on BiOBr doped biomass carbon according to claim 2, characterized in that, The detection system (2) comprises a detection system shell (201), a reaction pool cover (202), a reaction pool (203), a platinum wire electrode (204), a silver / silver chloride electrode (205), a working electrode (206) and an LED lamp (207); the platinum wire electrode (204), the silver / silver chloride electrode (205) and the working electrode (206) are fixedly installed through electrode installation holes a, b and c on the reaction pool cover (202), the three electrodes detect the target detection object in the reaction pool (203) and generate electric signal changes; the reaction pool cover (202) is matched with the opening on the reaction pool (203); the reaction pool (203) is installed in the detection system shell (201); the reaction pool (203) is used for placing the sample to be detected; the LED lamp (207) is installed in the detection system shell (201), the light emitted by the LED lamp (207) transmits through the reaction pool (203) and irradiates on the working electrode (206), so that the working electrode (206) is provided with a driving light source; and the detection system shell (201) provides a darkroom environment for the LED lamp (207) to reduce the influence of natural light.

4. The portable detection device for detecting microcystins based on BiOBr doped biomass carbon according to claim 2, characterized in that, The wiring hole B arranged on the partition plate (103) is used for placing the electric connecting line on the printed circuit board (105) in the groove 1, and the electric connecting line is led out from the hole on the control system shell (101) and connected with the detection electrode and the LED of the detection system (2).

5. The portable detection device for detecting microcystins based on BiOBr doped biomass carbon according to claim 2, characterized in that, The control system shell (101) is 54mm long, 22mm wide and 17mm high; the partition (103) is 20mm long and 10-20mm high; the groove 2 is a rectangular groove with a cross-sectional area of 44mm*20mm; the wiring hole B on the partition (103) is a rectangular hole with a size of 6mm*2mm; the groove 1 is a rectangular groove with a cross-sectional area of 20mm*7mm; and the hole A on the control system shell cover (102) is a rectangular hole with a size of 5mm*4mm.

6. The portable detection device for detecting microcystins based on BiOBr doped biomass carbon according to claim 3, characterized in that, The detection system shell (201) is internally provided with a groove 3 and a groove 4, the reaction pool (203) is fixed in the groove 4, and the reaction pool (203) can be pushed out of the detection system shell (201) through the push loading hole d provided on the detection system shell (201) to realize replacement of the detection object; and the LED lamp (207) is fixed in the groove 3, and the LED lamp (207) is aligned with the working electrode (206).

7. The portable detection device for detecting microcystins based on BiOBr doped biomass carbon according to claim 6, characterized in that, The detection system shell (201) is a cuboid with a length of 22mm and a width of 16mm; the groove 4 is a square hole with a side length of 12mm in cross section, and the depth is 45mm; the reaction pool (203) is a hollow cuboid with a side length of 12mm in cross section and a height of 45mm, and the wall thickness is 1-3mm; the reaction pool (203) is fixed in cooperation with the groove 4; and the reaction pool cover (202) is a cuboid with a side length of 16mm in cross section and a height of 8mm, and the inside is provided with an electrode mounting hole c with a hole diameter of 0.1-0.5mm for fixing the platinum wire electrode 204, an electrode mounting hole a with a hole diameter of 1-3mm for fixing the silver / silver chloride electrode 205, and an electrode mounting hole b with a hole diameter of 2-4mm for fixing the working electrode (206).

8. The portable detection device for detecting microcystins based on BiOBr doped biomass carbon according to claim 3, characterized in that, The detection system shell (201) and the reaction pool cover (202) are both prepared by using 3D printing technology and black material, meeting the requirement of darkroom detection; and the control system shell (101), the control system shell cover (102) and the partition (103) are all prepared by using 3D printing technology.

9. The portable detection device for detecting microcystins based on BiOBr doped biomass carbon according to claim 3, characterized in that, The platinum wire electrode (204), the silver / silver chloride electrode (205) and the working electrode (206) form a three-electrode detection system, which is prepared by the following method: First, BiOBr@BC is prepared, and the steps are as follows: Step 1, shrimp shell biomass carbon preparation The shrimp shell is cleaned and dried, and then crushed by a crusher to obtain shrimp shell powder. The shrimp shell powder is calcined in a tube furnace, and then immersed in a hydrochloric acid solution to remove impurities. After solid-liquid separation, the separated solid product is dried in an oven. Finally, the dried product is mechanically crushed in a ball mill, and the collected black powder-shaped biomass carbon material is denoted as BC. Step 2, preparation of BiOBr@BC A certain amount of bismuth nitrate pentahydrate is added to a glycol solution containing cetyltrimethylammonium bromide, and stirred thoroughly to obtain a uniform dispersion A; BC prepared in step 1 is added to dispersion A, and stirred thoroughly to obtain a mixture B; mixture B is transferred to a high-pressure reaction kettle, and a constant temperature reaction is carried out at a set temperature; after the reaction is completed, the solid is collected by centrifugation and washing, and dried in an oven to obtain a solid powder, which is denoted as BiOBr@BC; Wherein: in step 1, the tube furnace heating rate is set to 8℃ / min -1 , the holding temperature is 400℃, the holding time is 2h; the ball mill milling speed is 600r / min -1 , the crushing time is 0.5h; the hydrochloric acid solution concentration is 5%, the stirring treatment time is 12h; the solid-liquid separation is realized by a vacuum pump; the drying condition is 80℃ for 12h; In step 2, the bismuth nitrate pentahydrate is mixed with the glycol solution containing cetyltrimethylammonium bromide for 0.5 h; the reaction temperature of the mixed solution in the high-pressure reaction kettle is 140°C, and the reaction time is 12 h; the washing conditions are that deionized water and ethanol at 50°C are used for washing multiple times, and the material after washing is neutral; the drying conditions are that the drying is carried out at 50°C for 12 h; Secondly, a detection electrode is prepared, and the steps are as follows: (A1) BiOBr@BC is dispersed in N,N-dimethylformamide to prepare a suspension; (A2) 10-30 μL of the suspension in step (A1) is modified on an ITO electrode, and dried at room temperature to obtain a modified electrode, which is denoted as BiOBr@BC / ITO; 10-50 μL of an aptamer solution of MC-LR is dropped on the surface of the prepared BiOBr@BC / ITO electrode, and incubated at room temperature for 4 h; then, the electrode is washed with a buffer solution and ultrapure water, and dried at room temperature to obtain an aptamer / BiOBr@BC / ITO electrode, which is denoted as apt / BiOBr@BC / ITO; (A3) 10-50 μL of MC-LR solution with different concentrations is dropped on the apt / BiOBr@BC / ITO electrode to obtain an MC-LR / apt / BiOBr@BC / ITO electrode; (A4) A three-electrode detection system is established by taking the MC-LR / apt / BiOBr@BC / ITO electrode as a working electrode, a silver / silver chloride electrode as a reference electrode, and a platinum wire electrode as a counter electrode, which is used for detecting the concentration of MC-LR; wherein: in step (A1), the concentration of said BiOBr@BC is 2 mg mL -1 ; In step (A2), the sequence of the MC-LR aptamer is: 5'-GGC GCC AAA CAG GAC CAC CAT GAC AATTAC CCA TAC CAC CTC ATT ATG CCC CAT CTC CGC-3'; In step (A3), the MC-LR concentration is 1 x 10 -2 ~ 2 x 10 3 pM.

10. The method for detecting microcystins according to any one of claims 1-9, wherein the portable detection device is based on bismuth oxybromide doped biomass carbon for detecting microcystins, and the method comprises the following steps: 1) adding the sample to be detected into the detection device; 2) detecting the microcystins in the sample to be detected by the detection device; 3) obtaining the detection result of the microcystins in the sample to be detected. The following steps are implemented: S1, turn on the switch (104) to start the detection device, and control the LED lamp (207) in the slot 3 of the detection system (2) to emit excitation light by the electronic element (107) of the control system (1), and the excitation light irradiates on the working electrode (206) through the reaction cell (203); S2, the nanomaterial on the working electrode (206) enters an excited state after receiving the excitation light, and generates an electric current; S3, the detection target in the reaction cell (203) affects the separation of hole-electron pairs, thereby affecting the change of the electric current; S4, the control system (1) receives the electric current signal in real time, and processes the concentration of the detection target according to the electric current change corresponding to different concentrations of the detection target.

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