Water-voltammetry coupled photoelectrochemical self-powered electrochemical sensor for detecting enrofloxacin and preparation method thereof

Abstract

The application belongs to the field of electrochemical detection, and particularly relates to a novel water-vapor coupling photoelectric self-powered electrochemical sensor for detecting enrofloxacin and a preparation method thereof. A glass substrate is used as a substrate, a copper foil tape is used as a positive electrode and a negative electrode, CdS (cadmium sulfide) and a cobalt-based metal organic framework (ZIF-67) are used as water-vapor / photovoltaic materials to construct a heterojunction for preparing a water-vapor generator to realize sustainable power generation. The CdS / ZIF-67 heterojunction is beneficial to the separation of photo-generated carriers under illumination and synergistically enhances the water evaporation effect. An enrofloxacin (ENR) aptamer is assembled to construct a water-vapor / photovoltaic self-powered electrochemical sensor. With the help of split aptamers, the ENR detection exhibits high sensitivity and high specificity, and provides a new strategy for self-powered electrochemical detection. The water-vapor / photovoltaic self-powered electrochemical sensor has a wide detection range, high sensitivity and low detection limit.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of electrochemical detection, and particularly relates to a water-voltage effect coupled photoelectrochemical self-powered electrochemical sensor for detecting enrofloxacin and a preparation method thereof. BACKGROUND

[0002] Enrofloxacin (ENR) is a common antibiotic with less side effects as an antibacterial agent, and is widely used in the field of veterinary medicine. However, improper use of enrofloxacin can lead to its residues in the environment and some food, and then affect human health through the transmission of the food chain. At present, common methods for detecting enrofloxacin include enzyme-linked immunosorbent assay, fluorescence spectroscopy, high-performance liquid chromatography, etc. These methods have the disadvantages of expensive instruments and equipment, complex operation, low sensitivity, etc. Therefore, it is of great significance to develop a simple and efficient analysis method for detecting the content of enrofloxacin in water.

[0003] One of the main drawbacks of typical sensors is the need for an external power source or battery, which makes the sensor system more complex. Compared with traditional energy conversion devices, self-powered electrochemical sensors can convert chemical or mechanical energy into a detectable electrical signal. Due to the fact that they do not require an external voltage, have flexible structures, and simple equipment, they have become a research hotspot in the field of electrochemistry. As a promising emerging technology, self-powered electrochemical sensors have gradually been popularized in the fields of environmental monitoring, agriculture, food safety analysis, and gene detection. So far, there have been many energy generation methods that have been used to build high-performance self-powered electrochemical sensors. Among them, water-voltage power generation devices can be applied in various situations without additional input of mechanical energy. Through the direct interaction between materials and water, they can directly convert environmental energy into electrical energy output, and are a clean and pollution-free green new energy conversion technology.

[0004] Compared with a water-voltage cell (HVC), a photovoltaic cell has relatively high output power. Water-voltage-photovoltaic coupling can eliminate the dependence of the device on a single energy source and improve the output performance. By embedding a heterojunction in a water power generation device, the electrical power output of the device can be increased through the superposition of photovoltaic voltage and water power generation voltage. Therefore, the construction of a heterojunction is a key structural basis for designing such a coupled energy collection device. Split aptamer refers to two nucleic acid chains obtained by splitting a complete nucleic acid aptamer, which can combine to recognize the target when the target exists. Split aptamer often uses shorter nucleic acid chains, which can avoid the formation of complex secondary structures and is conducive to the formation of the configuration for recognizing the target. At the same time, it can also reduce the background signal generated by intermolecular interaction. With the help of split aptamer, a self-powered sensing platform based on water-voltage-photovoltaic coupled power generation device and supplemented with split aptamer has not been reported for electrochemical detection of enrofloxacin. SUMMARY

[0005] The application aims to provide a construction method of a water-voltaic photoelectric self-powered electrochemical sensor for sensitive enrofloxacin detection, which has the advantages of high sensitivity, low detection limit and wide detection range.

[0006] The application first provides a water-voltaic / photoelectric coupling self-powered electrochemical sensor for enrofloxacin detection, which takes a glass substrate as a substrate, takes copper foil tape as positive and negative electrodes, takes CdS / ZIF-67 composite material as power generation material to prepare a water-voltaic generator, assembles enrofloxacin aptamer, and constructs a water-voltaic / photoelectric coupling self-powered electrochemical sensor.

[0007] The enrofloxacin aptamer comprises a split aptamer 1 chain and a split aptamer 2 chain, the nucleotide sequence of the split aptamer 1 chain is 5'-ATC TCT GAG CCC GGG TTA TTT CAG GGG GA-3', and the nucleotide sequence of the split aptamer 2 chain is 5'-CCC ATC AGG GGG CTA GGC TAA CAC GGT TCG GC-3'.

[0008] The application further provides a preparation method of the water-voltaic / photoelectric self-powered electrochemical sensor for enrofloxacin detection, which comprises the following steps:

[0009] (1) Preparation of CdS powder:

[0010] A mixed solution (the concentration of cadmium nitrate is 48 mmol / L) with a molar ratio of cadmium nitrate, thiourea and glutathione of 1:1:0.6 is added into an autoclave under stirring. The reaction is carried out at 140-200 DEG C for 6-24 hours. The obtained product is centrifuged and washed with deionized water for several times, and then dried in a vacuum oven at 50-90 DEG C for 6-24 hours to obtain CdS powder.

[0011] (2) Preparation of ZIF-67:

[0012] In order to prepare ZIF-67, a methanol solution containing a water-soluble cobalt salt and a 2-methylimidazole methanol solution are provided respectively, and then the two solutions are mixed and stirred vigorously for 3-60 minutes. The mixed solution is left to stand at room temperature for 6-24 h, and the obtained precipitate is centrifuged, washed with methanol for several times and dried at 50-90 DEG C for 6-24 h. The water-soluble cobalt salt is cobalt nitrate hexahydrate, and the molar ratio of the cobalt nitrate hexahydrate to 2-methylimidazole is 1:4.

[0013] (3) Preparation of CdS / ZIF-67 composite water-voltaic cell:

[0014] CdS and ZIF-67 are added into a mixed solution of ethanol and water (Vethanol:Vultrapure water = 1:1) for ultrasonic dispersion to prepare a uniform CdS / ZIF-67 composite material suspension, which is drop-coated on a clean glass; wherein the mass of CdS is 25% to 75% of the total mass of CdS and ZIF-67. Copper foil tape is used as an electrode, and the upper and lower electrodes are pasted on the CdS / ZIF-67 glass substrate in the shape of "L"; the prepared device is dried at 50-80°C for 6-10h.

[0015] Preferably, the mass of CdS is 30% to 70% of the total mass of CdS and ZIF-67; more preferably, the mass of CdS is 50% of the total mass of CdS and ZIF-67, i.e. the mass ratio of CdS to ZIF-67 is 1:1.

[0016] (4) Preparation of aptamer sensor:

[0017] The water-voltaic cell power generation material prepared in step (3) is drop-coated with a certain concentration of enrofloxacin aptamer (ENR-2). After natural drying at room temperature, an aptamer sensor with selective recognition for enrofloxacin is obtained. The concentration of the aptamer is 2 μmol / L, and the drop-coating amount of the aptamer is 10-60 μL.

[0018] The nucleotide sequence of the enrofloxacin aptamer (ENR-2) is: 5'-CCC ATC AGG GGG CTA GGC TAA CAC GGT TCG GC-3'.

[0019] The application further provides an application of the above-mentioned water-voltaic-based self-powered electrochemical sensor in detecting enrofloxacin. A sample solution containing the enrofloxacin split aptamer 1 chain is drop-coated on the surface of the water-voltaic / light-electricity coupling self-powered electrochemical sensor, and is naturally dried at room temperature to allow the split aptamer 1 chain, enrofloxacin and split aptamer 2 chain to fully combine. Deionized water is used as an electrolyte, and the response value of short-circuit current under the test potential is measured under a xenon lamp light source. The standard curve method is used to calculate the concentration of enrofloxacin in the sample solution to be measured.

[0020] The specific detection steps are as follows:

[0021] S1, prepare a solution containing different concentrations of enrofloxacin;

[0022] Accurately weigh enrofloxacin, and prepare a standard solution using deionized water. The standard solution is sequentially diluted with ENR aptamer fragments (ENR-1) to obtain different concentrations of enrofloxacin standard solutions containing ENR aptamer, and the concentration range is 1.0 x 10 -140.1*10-3~1.0*10-3 mol / L -8 0.1*10-3~1.0*10-3 mol / L;

[0023] The nucleotide sequence of the enrofloxacin aptamer (ENR-1) is: 5'-ATC TCT GAG CCC GGG TTA TTT CAG GGG GA-3'.

[0024] S2, drawing of a standard curve:

[0025] A series of enrofloxacin (containing ENR-1) solutions with known concentrations are dropped on the surface of the prepared water-voltaic cell power generation material, and are naturally dried at room temperature;

[0026] The copper foil tape upper and lower electrodes are used as the positive and negative electrodes of the electrochemical test, CdS and ZIF-67 are used as the power generation material, and the enrofloxacin aptamer is assembled to form a water-voltaic self-powered system, deionized water is used as the electrolyte, the current of the xenon lamp light source is controlled to be 20 A, the horizontal distance from the light source outlet to the glass substrate is 15 cm, the short-circuit current response value is measured at a test potential of 0 V, a series of concentration-short-circuit current corresponding relationships are obtained, and then the standard curve of enrofloxacin is obtained, the linear relationship between the short-circuit current intensity after the addition of enrofloxacin and the logarithmic value of the enrofloxacin concentration is established, and the corresponding linear regression equation is obtained.

[0027] S3, sample detection, sample filtering and impurity removal, testing according to the above step 2 and obtaining the short-circuit current value, the obtained short-circuit current value is calculated by using the linear regression equation obtained in step S2, and the concentration of enrofloxacin in the sample is obtained.

[0028] As preferred, the concentration of the aptamer 1 chain in the sample solution to be detected is consistent with the concentration of the aptamer 2, which is 2 μmol / L.

[0029] As preferred, the combination reaction time of the water-voltaic-photovoltaic self-powered electrochemical sensor aptamer 1 chain, enrofloxacin and aptamer 2 chain is 25 min.

[0030] The beneficial effects of the present application are:

[0031] The present application assembles CdS and ZIF-67 composite materials, constructs a heterostructure, and prepares a novel self-powered electrochemical sensor based on water-voltaic-photovoltaic effect, further improves the electric output of the self-powered electrochemical system, establishes an electrochemical detection method for enrofloxacin, and provides a new detection strategy for an efficient self-powered electrochemical sensing system.

[0032] The features and advantages are described as follows:

[0033] (1) The application utilizes the composite of cadmium sulfide and cobalt-based metal organic framework ZIF-67 to assemble a water-voltage coupling photoelectric effect sensor. CdS has photoelectric effect characteristics and unique surface hydrophilicity, and is a suitable material for coupling water-voltage effect and photoelectric effect characteristics. Cobalt-based metal organic framework (ZIF-67) has a unique porous structure and good loading capacity, in addition, the heterojunction based on MOF can hinder the recombination of photo-generated charges and improve the light capture efficiency. The CdS / ZIF-67 heterostructure is built into a water-voltage power generation device, and the power output of the water-voltage device is further improved by superimposing the photovoltaic voltage and the water-voltage power generation voltage.

[0034] (2) The application adopts a short nucleic acid chain split nucleic acid aptamer, avoids forming a complex secondary structure, is conducive to the formation of the configuration for recognizing the target enrofloxacin, enhances the specificity of the sensor, and reduces the background signal generated by intermolecular interaction. The prepared water-voltage-photoelectric coupling electrochemical sensor has good stability and recovery rate, high specificity and high sensitivity, a wide linear range and a low detection limit, can be used for the determination of enrofloxacin in actual samples, and has a wide application prospect in environmental monitoring and food analysis. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a brief flowchart of the preparation of the sensor in the application and the detection of enrofloxacin;

[0036] Figure 2 is the current signal of the CdS / ZFI-67 composite material battery with different mass ratios;

[0037] Figure 3 is the current signal measured by the battery with different drop amounts;

[0038] Figure 4 is the energy band diagram of the CdS / ZIF-67 heterojunction;

[0039] Figure 5 is the short-circuit current response diagram of the sensor to different concentrations of enrofloxacin (from a to g: 10 -14 to 10 -8 M). Among them, the concentration of enrofloxacin is arranged from high to low according to the peak value of the curve, (a) 1×10 -14 mol / L, (b) 1×10 -13 mol / L, (c) 1×10 -12 mol / L, (d) 1×10 -11 mol / L, (e) 1×10 -10 mol / L, (f) 1×10 -9 mol / L, (g) 1×10 -8 mol / L;

[0040] Figure 6 is the corresponding linear calibration curve of the short-circuit current response of the sensor to different concentrations of enrofloxacin.

[0041] Figure 7 is the current signal measured based on different materials. Wherein curves a, b, c represent pure CdS, pure ZIF-67, CdS / ZIF-67 composite material respectively. DETAILED DESCRIPTION

[0042] The application will be further described in detail below in combination with examples. EXAMPLE

[0043] As shown in Figure 1 Water-voltaic-photovoltaic self-powered electrochemical sensor, copper foil tape as positive and negative electrode, based on CdS / ZIF-67 composite material to construct heterojunction, preparation of water-voltaic-photovoltaic effect coupling power generation device, and assembly of split enrofloxacin aptamer, composition of self-powered electrochemical aptamer sensor for detection of enrofloxacin.

[0044] The preparation method of the water-voltaic self-powered electrochemical sensor has the following steps:

[0045] (1) Preparation of CdS powder:

[0046] A mixed solution (the concentration of cadmium nitrate is 48 mmol / L) with a molar ratio of cadmium nitrate, thiourea and glutathione of 1:1:0.6 was added to a 50 mL autoclave under stirring. The reaction was carried out at 180℃ for 12 hours. The obtained product was washed several times by centrifugation with methanol, and then dried in a vacuum oven at 60℃ for 12 hours to obtain CdS powder.

[0047] (2) Preparation of ZIF-67 powder:

[0048] In order to prepare ZIF-67, 0.873 g of cobalt nitrate hexahydrate was dissolved in methanol (30 mL) to form a solution. In another solution, 0.984 g of 2-methylimidazole was dissolved in methanol (10 mL). Then the two solutions were mixed and stirred vigorously for 3 minutes. The mixed solution was left to stand at room temperature overnight, and the obtained precipitate was centrifuged and washed several times with methanol, and then dried at 60℃ for 12 h to obtain ZIF-67 powder.

[0049] (3) Preparation of CdS / ZIF-67 composite water-voltaic cell:

[0050] The composite material of CdS and ZIF-67 with different mass ratios (Vethanol:Vultrapure water = 1:1) is prepared into a 10 mg / L turbidity solution, and 200-600 μL is dropped on a clean glass. The equipment is placed in a vacuum drying oven at 60°C and dried overnight, and the CdS / ZIF-67 composite film material is obtained after drying. The mass ratio of CdS to ZIF-67 is 3:1, 2:1, 1:1, 1:2, and 1:3. The current signals measured by the batteries with different mass ratios of CdS to ZIF-67 are compared in Figure 2 . It can be seen from Figure 2 that the current signal is the strongest when the mass ratio of CdS to ZIF-67 is 1:1.

[0051] The composite material of CdS and ZIF-67 with a mass ratio of 1:1 (Vethanol:Vultrapure water = 1:1) is prepared into a 10 mg / L turbidity solution, and dropped on a clean glass. The equipment is placed in a vacuum drying oven at 60°C and dried overnight, and the CdS / ZIF-67 composite film material is obtained after drying. The dropping amount of the CdS / ZIF-67 suspension is 200 μL, 300 μL, 400 μL, 500 μL, and 600 μL. The current signals measured by the batteries with different dropping amounts of CdS / ZIF-67 are compared in Figure 3 . It can be seen from Figure 3 that the current signal is the strongest when the dropping amount of CdS / ZIF-67 is 500 μL.

[0052] (4) Preparation of aptamer sensor:

[0053] 20 μL of enrofloxacin aptamer solution with a concentration of 2 μmol / L is added to the surface of the water-activated battery power generation material with a dropping amount of 500 μL prepared in step (3). The aptamer sensor with selective recognition for enrofloxacin is obtained after natural drying at room temperature.

[0054] The nucleotide sequence of the above enrofloxacin aptamer (ENR-2) is as follows:

[0055] Aptamer: 5'-CCC ATC AGG GGG CTA GGC TAA CAC GGT TCG GC-3'.

[0056] (5) Test of short-circuit current and drawing of standard curve:

[0057] An enrofloxacin solution is prepared. A certain mass of enrofloxacin is accurately weighed, and a standard solution is prepared using deionized water. The standard solution is sequentially diluted with an ENR aptamer (ENR-1) fragment, and different concentration enrofloxacin standard solutions containing 2 μM ENR aptamer 1 are obtained, with a concentration range of 1.0 x 10 -14mol / L~1.0×10 -8 mol / L;

[0058] The enrofloxacin aptamer (ENR-1) nucleotide sequence is: 5'-ATC TCT GAG CCC GGG TTA TTTCAG GGG GA-3'.

[0059] In the water-voltaic photoelectric self-powered electrochemical sensor, copper foil tape is used as the positive and negative electrodes, a CdS / ZIF-67 composite material heterojunction is constructed, and the band structure is as shown in Figure 4 Based on the heterostructure, a split enrofloxacin aptamer is assembled to form a dual energy conversion effect self-powered system for enrofloxacin detection. The incubation time of the self-powered electrochemical aptamer sensor is 25 min, the electrode clip is fixed on the copper foil electrode as an extension to facilitate connection during measurement, ultrapure water is used for power generation measurement, the current of the xenon lamp light source is controlled to be 20 A, the horizontal distance from the light source outlet to the glass substrate is 15 cm, and the short-circuit current response value is measured at a test potential of 0 V, as shown in Figure 5 The electrodes containing ENR aptamer (2 μM) and different concentrations of enrofloxacin are tested, and the concentrations of enrofloxacin from top to bottom according to the peak value of the curve are as follows:

[0060] (a) 1×10 -14 mol / L ,(b) 1×10 -13 mol / L ,(c) 1×10 -12 mol / L ,(d) 1×10 -11 mol / L ,(e) 1×10 -10 mol / L ,(f) 1×10 -9 mol / L ,(g) 1×10 -8 mol / L

[0061] As shown in Figure 6 , the linear relationship between the short-circuit current after adding enrofloxacin and the logarithmic value of the enrofloxacin concentration is established, and the corresponding linear regression equation is: I SC-max (nA) = -26.65862 log C(mol / L)-88.41775;The detection range of the linear regression equation is 1.0×10 -14 ~1.0×10 -8 mol / L, and the lowest detection limit is 1.46×10 -15 mol / L.

[0062] (6) Detection of samples:

[0063] A certain amount of filtered wastewater was taken, enrofloxacin solution was prepared, and was used for electrochemical detection. The enrofloxacin concentration in the sample to be detected was calculated according to the linear regression equation corresponding to step (5) above, and the results are shown in Table 1.

[0064] Comparative Example 1

[0065] (1) Preparation of CdS water-activated cell:

[0066] The glass substrate was cleaned in deionized water and ethanol for half an hour, then washed with deionized water and dried in an oven; a mixed solution of cadmium nitrate, thiourea and glutathione with a molar ratio of 1:1:0.6 (the concentration of cadmium nitrate was 48 mmol / L) was added to a 50 mL autoclave under stirring. The reaction was carried out at 180℃ for 6-24 hours. The obtained product was washed several times by centrifugation with methanol, and then dried in a vacuum oven at 50-80℃ for 12 hours to obtain CdS powder. Anhydrous ethanol and deionized water were mixed in a volume ratio of 1:1 to prepare a turbid solution, and ultrasonic dispersion was carried out for 20-50 min to obtain a uniform CdS suspension. Copper foil tape was used as the positive and negative electrodes of the "L" shaped water-activated cell device.

[0067] (2) Measurement of short-circuit current and preparation of standard curve:

[0068] A self-powered system was formed with glass substrate as substrate, copper foil tape as positive and negative electrodes, and CdS as power generation material. The short-circuit current of the CdS-based water-activated-light photo self-powered electrochemical sensor was measured, and the measurement method was the same as in the examples. The test results are shown in Figure 7 (figure a);

[0069] The CdS-based water-activated-light photo self-powered electrochemical sensor was used for the detection of enrofloxacin in water samples, and the detection method was the same as in the examples. The results are shown in Table 1.

[0070] Comparative Example 2

[0071] (1) Preparation of ZIF-67 water-activated cell

[0072] The glass substrate was cleaned in deionized water and ethanol for half an hour, then washed with deionized water and dried in an oven; 0.873 g of cobalt nitrate hexahydrate was dissolved in methanol (30 mL) to form a solution. In another solution, 0.984 g of 2-methylimidazole was dissolved in methanol (10 mL). Then the two solutions were mixed and stirred vigorously for 3-60 minutes. The mixed solution was left at room temperature, the resulting precipitate was centrifuged, washed with methanol several times, dried at 50-80°C for 6-24 h, and ZIF-67 powder was obtained. Anhydrous ethanol and deionized water were added in a volume ratio of 1:1 to prepare a turbid solution, and ultrasonic dispersion was performed for 20-50 min to obtain a uniform ZIF-67 suspension. The copper foil tape was used as the positive and negative electrodes of the "L" shape, and the ZIF-67 water-activated battery device was obtained after drying.

[0073] (2) Test of short-circuit current and drawing of standard curve:

[0074] The glass substrate was used as the substrate, the copper foil tape was used as the positive and negative electrodes, and the ZIF-67 was used as the power generation material to form a self-powered system. The short-circuit current of the water-activated-light photo self-powered electrochemical sensor based on ZIF-67 was measured, and the measurement method was the same as in the example, and the test results are shown in Figure 7 (figure b);

[0075] The water-activated-light photo self-powered electrochemical sensor based on ZIF-67 was used to detect enrofloxacin in water samples, and the detection method was the same as in the example, and the results are shown in Table 1.

[0076] As shown in Figure 7 , the short-circuit current signals of different materials under light were studied. Curves a, b and c show the short-circuit current values of the self-powered electrochemical sensors of pure CdS, pure ZIF-67 and CdS / ZIF-67 heterojunction, respectively. Under light conditions, the short-circuit current value of the composite material is increased by about 5-6 times, and the stability is obviously improved. The results show that without using CdS / ZIF-67 composite material, the sensor prepared by using CdS or ZIF-67 alone has too low electric signal and poor stability, which greatly limits the subsequent detection work. Therefore, it is feasible to construct a heterojunction based on CdS / ZIF-67 to synergistically enhance the water-activated-light photo effect and prepare a CdS / ZIF-67 water-activated-light photo self-powered electrochemical sensor.

[0077] Table 1 Determination results of enrofloxacin in water samples

[0078] .

[0079] As shown in Table 1, the sample is detected in parallel for 3 times, the relative standard deviation is less than 5%, and the recovery of standard addition is in the range of 97%-102%. The above results show that the sensor prepared without CdS / ZIF-67 / apt / glass and prepared separately with CdS / glass or ZIF-67 / glass cannot detect enrofloxacin, and the application for detecting enrofloxacin in wastewater is feasible.

[0080] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacement or change according to the technical scheme and concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A water-voltammetry coupled photoelectrochemical self-powered electrochemical sensor for enrofloxacin detection, characterized in that, The application discloses a self-powered electrochemical sensor based on water-vapor photovoltaic coupling, which is prepared by using a glass substrate, copper foil tape as positive and negative electrodes, and CdS / ZIF-67 composite material as power generation material. The preparation method of the electrochemical sensor comprises the following specific steps: (1) CdS and ZIF-67 are ultrasonically dispersed in a mixed solution of ethanol and water to prepare a uniform CdS / ZIF-67 composite material suspension, which is then dropped on a clean glass substrate to obtain a CdS / ZIF-67 glass substrate; copper foil tape is used as electrodes, and upper and lower electrodes in the shape of "L" are pasted on the CdS / ZIF-67 glass substrate, which is then dried at 50-80 DEG C for 6-10 hours to obtain a water-vapor battery device; (2) coupling enrofloxacin aptamer: the aptamer solution containing split aptamer 2 chain is added dropwise on the surface of the water-vapor battery device prepared in step (1), and is naturally dried at room temperature to obtain an aptamer sensor with selective recognition to enrofloxacin.

2. The water-voltammetry photoelectro-energized electrochemical sensor for enrofloxacin detection according to claim 1, characterized in that, The CdS is prepared by the following method: a mixed solution of cadmium nitrate, thiourea and glutathione with a molar ratio of 1:1:0.6 is added into a high-pressure kettle under stirring, and is reacted at 140-200 DEG C for 6-24 hours; The product is collected by centrifugation, washed for several times, and dried at 50-90 DEG C for 6-24 hours to obtain CdS powder.

3. The water-voltammetry coupled photo-electrochemically self-powered electrochemical sensor for the detection of enoxacin according to claim 1, wherein, The ZIF-67 is prepared by the following method: a methanol solution of water-soluble cobalt salt and a methanol solution of 2-methylimidazole are provided respectively, the two solutions are mixed and stirred vigorously for 3-60 minutes to obtain a mixed solution; the mixed solution is left to stand at room temperature for 6-24 hours, and the obtained precipitate is centrifuged and washed with methanol for several times and dried at 50-90 DEG C for 6-24 hours; wherein the molar ratio of the water-soluble cobalt salt to 2-methylimidazole is 1:

4.

4. A method for the preparation of a water-voltammetry photoelectrochemical self-powered sensor for the detection of enrofloxacin according to claim 1, characterized by, The preparation method of the electrochemical sensor comprises the following specific steps: (1) CdS and ZIF-67 are ultrasonically dispersed in a mixed solution of ethanol and water to prepare a uniform CdS / ZIF-67 composite material suspension, which is then dropped on a clean glass substrate to obtain a CdS / ZIF-67 glass substrate; copper foil tape is used as electrodes, and upper and lower electrodes in the shape of "L" are pasted on the CdS / ZIF-67 glass substrate, which is then dried at 50-80 DEG C for 6-10 hours to obtain a water-vapor battery device; (2) coupling enrofloxacin aptamer: the aptamer solution containing split aptamer 2 chain is added dropwise on the surface of the water-vapor battery device prepared in step (1), and is naturally dried at room temperature to obtain an aptamer sensor with selective recognition to enrofloxacin.

5. The method for the preparation of water-voltammetry photoelectro-energized electrochemical sensor for the detection of enoxacin according to claim 4, characterized by, The mass of CdS in the CdS / ZIF-67 composite material suspension of step (1) accounts for 25% to 75% of the total mass of CdS and ZIF-67; and / or the mass concentration of the CdS / ZIF-67 composite material suspension of step (1) is 10 mg / mL.

6. The method for the preparation of water-voltammetry photoelectro- self-powered electrochemical sensor for enoxacin detection according to claim 4, characterized in that, The drop coating amount of the CdS / ZIF-67 composite material suspension in step (1) is 300-700 μL, and the drop coating area is 1.5 x 3.0 cm 2 .

7. The method for preparing water-voltammetry coupled photoelectric self-powered electrochemical sensor for enoxacin detection according to claim 4, characterized in that, The concentration of the enrofloxacin split aptamer 2 chain in the aptamer solution of step (2) is 2 μmol / L; the drop coating amount of the aptamer solution is 10-60 μL.

8. The method for preparing water-voltammetry coupled photoelectric self-powered electrochemical sensor for enoxacin detection according to claim 4, characterized in that, The CdS is prepared by the following method: a mixed solution of cadmium nitrate, thiourea and glutathione with a molar ratio of 1:1:0.6 is added to an autoclave under stirring, and then reacted at 140-200 ℃ for 6-24 hours; The product is collected by centrifugation, washed several times, and dried at 50-90 ℃ for 6-24 hours to obtain CdS powder.

9. The method for preparing water-voltammetry coupled photoelectric self-powered electrochemical sensor for enoxacin detection according to claim 4, characterized in that, The ZIF-67 is prepared by the following method: a methanol solution of water-soluble cobalt salt and a methanol solution of 2-methylimidazole are provided respectively, the two solutions are mixed and stirred vigorously for 3-60 minutes to obtain a mixed solution; the mixed solution is left to stand at room temperature for 6-24 hours, the obtained precipitate is centrifuged and washed with methanol several times, and dried at 50-90 ℃ for 6-24 hours; wherein the molar ratio of water-soluble cobalt salt to 2-methylimidazole is 1:

4.

10. Use of a water-voltammetry photoelectro-energized electrochemical sensor for the detection of enrofloxacin according to any one of claims 1-3, characterized in that, The test sample solution containing the enrofloxacin split aptamer 1 chain is drop coated on the surface of the water-voltaic coupled photoelectric self-powered electrochemical sensor, and naturally dried at room temperature to allow the split aptamer 1 chain, enrofloxacin and split aptamer 2 chain to fully combine; the response value of short-circuit current at the test potential is measured under a xenon lamp light source with deionized water as the electrolyte, and the concentration of enrofloxacin in the test sample solution is calculated by using the standard curve method.

11. The use of water-voltammetry photoelectrochemically self-powered electrochemical sensor for enoxacin detection according to claim 10, characterized in that, The combination time of the split aptamer 1 chain, enrofloxacin and split aptamer 2 chain is 10-60 min.

12. The use of water-voltammetry coupled photo-electrochemically self-powered electrochemical sensor for enoxacin detection according to claim 10, characterized in that, The current of the xenon lamp light source is controlled to be 20 A, the horizontal distance from the light source outlet to the glass substrate is 15 cm, and the test is performed at a test potential of 0 V.

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