CN112461904B - Preparation method and application of photoelectrochemical aptamer sensor for detecting enrofloxacin - Google Patents
Preparation method and application of photoelectrochemical aptamer sensor for detecting enrofloxacin Download PDFInfo
- Publication number
- CN112461904B CN112461904B CN202011067812.XA CN202011067812A CN112461904B CN 112461904 B CN112461904 B CN 112461904B CN 202011067812 A CN202011067812 A CN 202011067812A CN 112461904 B CN112461904 B CN 112461904B
- Authority
- CN
- China
- Prior art keywords
- ldh
- aptamer
- electrode
- ito
- enrofloxacin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
- G01N27/305—Electrodes, e.g. test electrodes; Half-cells optically transparent or photoresponsive electrodes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/416—Systems
- G01N27/4163—Systems checking the operation of, or calibrating, the measuring apparatus
Abstract
The invention belongs to the technical field of photoelectrochemistry and analysis and detection, and relates to a preparation method and application of a photoelectrochemical aptamer sensor for detecting enrofloxacin. The method comprises the following steps: preparing a sulfurized LDH/g-CN composite material by a solvothermal method, and then preparing a sulfurized LDH/g-CN-ITO electrode; finally, preparing a sulfurated LDH/g-CN-aptamer-ITO electrode; the composite material prepared by the invention has high-efficiency light absorption capacity and rapid charge transmission/separation capacity, explores the excellent photoelectric properties of the composite material, widens the application of LDH (layered double hydroxide) based materials in the photoelectric field, and simultaneously promotes the development of graphite-like phase carbon nitride-based heterojunction in the photoelectric detection field. When the prepared photoelectrochemistry aptamer sensor detects enrofloxacin, the detection limit reaches 0.34fmol/L, and the photoelectrochemistry aptamer sensor has the advantages of higher detection sensitivity and selectivity, low cost consumption, portability, miniaturization and the like.
Description
Technical Field
The invention belongs to the technical field of photoelectrochemistry and analysis and detection, and relates to a preparation method and application of a photoelectrochemical aptamer sensor for detecting enrofloxacin.
Background
Photoelectrochemical (PEC) detection has attracted considerable attention as a rapid, simple method of detection and analysis. PEC technology combines the advantages of both methods compared to traditional electrochemical and optical methods, thereby improving sensitivity and signal-to-noise ratio. Essentially, the principle of the PEC analysis method is that a semiconductor is used as an active species, under the irradiation of excitation light, photo-generated electrons are separated from holes, and then the active species captures the electrons or the holes to perform a redox reaction with a target detection object, so as to form a photovoltage or a photocurrent. Since the excitation light source of the PEC analysis method is completely separated from the detection signal, the background noise can be greatly reduced, and therefore, the PEC electrochemical analysis method has higher sensitivity compared with the traditional electrochemical analysis method. Compared with the traditional optical method, the PEC analysis method has the advantages of low instrument cost, miniaturization and the like.
Enrofloxacin (ENR), a third-generation fluoroquinolone antibiotic, is a highly effective antibacterial drug widely used in disease prevention and treatment in livestock and poultry farming and aquaculture (x.y.liu, j.ren, l.h.su, X, gao, y.w.tang, t.ma, l.j.zhu, j.r.li, biosens.87 (2017) 203-208). However, residual ENR can cause some health hazards (f.yu, s.yu, l.yu, y.li, y.wu, h.zhang, l.qu, p.b.harrington, food chem.149 (2014) 71-75). Therefore, it is important to develop an efficient detection method for detecting ENR residues. The aptamer is an RNA or DNA fragment which can be specifically and efficiently combined with ligands such as proteins or metabolites, and the aptamer is combined with PEC as a biological recognition element, so that the photoelectrochemical aptamer sensor which can be constructed can realize high-sensitivity and high-selectivity detection on ENR.
Disclosure of Invention
The invention aims to provide a sulfurized Layered Double Hydroxide (LDH)/graphite-like phase carbon nitride (g-CN) photoelectric active material, and a photoelectrochemistry aptamer sensor is constructed by using the material to detect enrofloxacin. Through the synergistic effect of the LDH and the sulfide cocatalyst, the charge transfer of the composite material is accelerated, the effective separation of a photoproduction electron-hole pair is promoted, and more excellent photoelectric properties are obtained; in addition, an aptamer is introduced to serve as a specific recognition element, so that high-selectivity and high-sensitivity detection of enrofloxacin is realized.
The present invention achieves the above technical objects by the following technical means.
A preparation method of a photoelectrochemical aptamer sensor for detecting enrofloxacin comprises the following steps:
(1) Preparation of a sulphided LDH/g-CN composite by solvothermal method:
firstly, weighing a certain amount of melamine or urea, and obtaining g-CN by a two-step calcination method;
then weighing a certain amount of divalent metal salt, trivalent metal salt and g-CN into a reaction kettle with a polytetrafluoroethylene lining, adding deionized water, and fully dissolving; adding a certain amount of urea and ammonium fluoride into the solution, continuously stirring until the urea and the ammonium fluoride are uniformly mixed, carrying out constant-temperature hydrothermal reaction, taking out the reaction kettle after the reaction is finished, and naturally cooling to room temperature; centrifuging the sample, washing with alcohol and water for several times, and drying in a vacuum oven at constant temperature to obtain LDH/g-CN;
then, weighing a certain amount of LDH/g-CN and sulfur source in a reaction kettle with a polytetrafluoroethylene lining, adding deionized water, continuously stirring, putting the high-pressure kettle in an oven for hydrothermal reaction, removing the reaction kettle after the reaction is finished, and naturally cooling to room temperature; and centrifuging to collect a sample, washing with water and alcohol for several times, and drying to obtain the LDH sulfide/g-CN.
The temperature of the two-step calcination is 400-700 ℃, the calcination rates of the first step and the second step are 2-5 ℃/min and 1-2 ℃/min respectively, and the calcination time of the first step and the second step is 2-4 h and 2-8 h respectively.
The dosage proportion of the divalent metal salt, the trivalent metal salt, g-CN, deionized water, urea and ammonium fluoride is 0.25-1.25 mmol:0.04 to 1.25mmol: 0.08-0.2 g:20mL of: 4-5 mmol: 0.5-1.5 mmol, the temperature of the constant temperature hydrothermal reaction is 80-140 ℃, and the time is 15-24 h; the temperature of the vacuum drying oven is 60 ℃, and the drying time is 12h.
The dosage ratio of the LDH/g-CN to the sulfur source is 0.05-0.1 g: 0.03-0.12 mmol, and the hydrothermal reaction temperature of the autoclave in a baking oven is 80-140 ℃ for 1-4 h.
(2) Preparation of an LDH sulfide/g-CN-ITO electrode:
dispersing a certain amount of a vulcanized LDH/g-CN composite material in deionized water, and performing ultrasonic treatment until the dispersion is uniform to obtain a stable suspension; and secondly, dripping the suspension liquid on the surface of ITO conductive glass, drying under an infrared lamp, washing by deionized water, and airing at room temperature to obtain the LDH/g-CN-ITO sulfide electrode.
The concentration of the suspension is 1.0mg/mL, and the dosage is 50 mu L.
(3) Preparing a vulcanized LDH/g-CN-aptamer-ITO electrode:
and (3) transferring a certain amount of Enrofloxacin (ENR) aptamer by using a liquid transfer gun to be dripped on the surface of the LDH sulfide/g-CN-ITO electrode prepared in the step (2), naturally drying at room temperature, washing with deionized water, and airing at room temperature to obtain the photoelectrochemical aptamer sensor, namely the LDH sulfide/g-CN-aptamer-ITO.
The concentration and dosage ratio of the enrofloxacin aptamer is 0.5-2.0 mu mol/L:20 mu L of the solution; the sequence of the enrofloxacin aptamer is 5.
The application of the photoelectrochemical aptamer sensor prepared by the invention in detecting enrofloxacin comprises the following specific steps:
taking the prepared LDH/g-CN-aptamer-ENR-ITO electrode as a working electrode, ag/AgCl as a reference electrode, pt as a counter electrode, taking a phosphate buffer solution as an electrolyte, and measuring a photocurrent response value of the electrode under zero-volt bias to obtain a series of concentration-photocurrent corresponding relations so as to obtain a standard curve of enrofloxacin;
taking the prepared LDH sulfide/g-CN-aptamer-ENR-ITO electrode as a working electrode, ag/AgCl as a reference electrode, pt as a counter electrode, taking phosphate buffer solution as electrolyte, measuring the photocurrent response value of the reference electrode under zero-volt bias, and substituting the photocurrent value into a standard curve for conversion to obtain the concentration of ENR in the detection liquid.
In the step 1, the dosage and concentration ratio of ENR is 20 muL: 1fmol/L-100 nmol/L; the phosphoric acid buffer solution was prepared by preparing 0.1mol/L sodium dihydrogen phosphate and disodium hydrogen phosphate to adjust the pH to 7.0, and the concentration was 0.1mol/L.
In the step 2, the phosphoric acid buffer solution is prepared by preparing 0.1mol/L sodium dihydrogen phosphate and disodium hydrogen phosphate for intermodulation, so that the pH value is 7.0, and the concentration of the phosphoric acid buffer solution is 0.1mol/L.
The invention has the following advantages:
(1) In view of the synergistic introduction of LDH and a metal sulfide cocatalyst, the composite material prepared by the invention has high-efficiency light absorption capacity and rapid charge transmission/separation capacity, explores the excellent photoelectric properties of the LDH material, widens the application of the LDH material in the photoelectric field, and simultaneously promotes the development of graphite-like phase carbon nitride-based heterojunction in the photoelectric detection field.
(2) The detection means used by the invention has the advantages of higher detection sensitivity and selectivity, low cost consumption, portability, miniaturization and the like.
(3) Due to the facts that the sulfurated LDH/g-CN composite material is used as a photoelectric active material and the aptamer is used as a specific recognition substance, high-efficiency detection of enrofloxacin can be achieved, and the method has obvious practicability.
Drawings
FIG. 1 shows NiS 2 X-ray diffraction (XRD) pattern of/NiFe LDH/g-CN composite material, wherein a is g-CN, b is NiFe LDH, c is NiFe LDH/g-CN, d is NiS 2 /NiFe LDH/g-CN。
FIG. 2 shows NiS 2 And (3) Transmission Electron Microscope (TEM) and high power transmission electron microscope (HRTEM) images of the/NiFe LDH/g-CN composite material, wherein a is the TEM and b is the HRTEM image.
FIG. 3 shows NiS 2 Solid ultraviolet Diffuse Reflection (DRS) diagram of/NiFe LDH/g-CN composite material, wherein a is g-CN, b is NiFe LDH, c is NiFe LDH/g-CN, d is NiS 2 /NiFe LDH/g-CN。
FIG. 4 shows NiS 2 Electrochemical Impedance (EIS) diagram of/NiFe LDH/g-CN composite material, wherein a is g-CN-ITO, b is NiFe LDH/g-CN-ITO, and c is NiS 2 /NiFe LDH/g-CN-ITO。
FIG. 5 shows NiS 2 The photoelectromogram of the/NiFe LDH/g-CN composite material is shown in the specification, wherein a is g-CN-ITO, b is NiFe LDH/g-CN-ITO, and c is NiS 2 NiFe LDH/g-CN-ITO, d is NiS 2 NiFe LDH/g-CN-aptamer-ITO, e is NiS 2 /NiFe LDH/g-CN-aptamer-ENR-ITO。
FIG. 6 shows NiS 2 The photoelectric signal response diagram of/NiFe LDH/g-CN-aptamer-ITO detecting ENR, wherein a is a photoelectric current diagram obtained by detecting ENR with different concentrations, and b is a linear relation diagram of ENR concentration-photoelectric current increment.
Detailed Description
The present invention is further described below with reference to specific examples to enable those skilled in the art to better understand the present invention, but the scope of the present invention is not limited to the following examples.
Example 1:
(1) The preparation of g-CN powder adopts a two-step calcination method: weighing 2.0g of melamine, putting the melamine into a 10mL crucible, then putting the crucible into a muffle furnace, and calcining at 550 ℃, wherein the heating rate is 5 ℃/min, and the calcining time is 4h; and then, heating the cooled bulk-phase carbon nitride to 550 ℃ again at a fixed heating rate of 2 ℃/min, keeping the temperature for 8 hours, and cooling to obtain g-CN.
(2) The NiFe LDH/g-CN material is synthesized by a solvothermal reaction in one step: first, 0.25mmol of NiCl was weighed 2 ·6H 2 O，0.04mmol FeCl 3 ·6H 2 O and 0.08g of-CN are dispersed in 20mL of deionized water and stirred for 30min; then, 5mmol of urea and 1.5mmol of NH were added 4 F, adding the mixture into the solution, and stirring for 10min. Finally, the solution was transferred to a 25mL Teflon lined reactor and held in an oven at 120 ℃ for 15h. And centrifuging the prepared sample, repeatedly washing the sample by using deionized water and ethanol, and drying the sample in a vacuum oven at the temperature of 60 ℃ for 12 hours to obtain the NiFe LDH/g-CN.
(3)NiS 2 The composite material of/NiFe LDH/g-CN is synthesized by a one-step solvothermal method: 0.05g of NiFe LDH/g-CN and 0.005g of thioacetamide are weighed and dispersed in 20mL of deionized water to be stirred for 30min; after stirring was complete, the solution was transferred to a 25mL Teflon lined reactor and held in an oven at 120 ℃ for 3h. Centrifuging the prepared sample, repeatedly washing with deionized water and ethanol, and drying in an oven at 60 deg.C for 12h to obtain NiS 2 /NiFe LDH/g-CN。
(4) Preparation of photoelectrochemical aptamer sensor: firstly, an ITO conductive glass pretreatment process is carried out, wherein ITO conductive glass is sequentially and ultrasonically cleaned in deionized water and ethanol for half an hour, and then is repeatedly washed by deionized water. And then putting the conductive glass into 0.1mol/L NaOH aqueous solution, boiling the conductive glass, keeping the boiling for 30min, washing the conductive glass by using deionized water and drying the conductive glass for later use. Configuration of 1mg/mL NiS 2 Putting the aqueous solution of/NiFe LDH/g-CN into an ultrasonic machine for ultrasonic dispersion to obtain stable suspension; then, 50. Mu.L of the suspension liquid was applied onto the pretreated ITO conductive glass, and dried under an infrared lamp 30min, the obtained modified electrode is recorded as NiS 2 NiFe LDH/g-CN-ITO. Next, 20. Mu.L of enrofloxacin aptamer (concentration 1.5. Mu. Mol/L) was pipetted with a pipette and applied dropwise to the NiS 2 Drying the surface of the/NiFe LDH/g-CN-ITO electrode for 12h at room temperature, washing with deionized water, and continuously drying at room temperature to obtain the photoelectrochemical aptamer sensor which is recorded as NiS 2 /NiFe LDH/g-CN-aptamer-ITO。
(5) Preparation of target detection object ENR: ENRs with concentrations of 1fmol/L,10fmol/L,0.1pmol/L,1pmol/L,10pmol/L,0.1nmol/L,1nmol/L,10nmol/L and 100nmol/L are respectively prepared to be detected.
(6) Photoelectrochemical detection methods and conditions: electrochemical experiments used the CHI660E electrochemical workstation (shanghai chen instruments ltd) with a traditional three-electrode system: the modified electrode is a working electrode, the platinum wire electrode is a counter electrode, and the saturated Ag/AgCl electrode is a reference electrode. The excitation light source was a 300W xenon lamp (PLS-SXE 300, beijing Pofely Tech Co., ltd.). Electrochemical experiments were all performed in phosphate buffered solution (0.1 mol/L, pH = 7.0) at room temperature without any bias applied. EIS experiments in the presence of 5mmol/L Fe (CN) 6 3-/4- And 0.1mol/L KCl in a phosphate buffer solution (0.1 mol/L, pH = 7.0), in a frequency range of 0.01Hz to 10kHz, at an initial potential of 0.24V, and at an AC amplitude of 5mV.
Example 2:
(1) The g-CN powder is prepared by adopting a two-step calcination method: weighing 4.0g of urea, putting the urea into a 10mL crucible, then putting the crucible into a muffle furnace, and calcining at 550 ℃, wherein the heating rate is 5 ℃/min, and the calcining time is 2h; then, the cooled sample is ground into powder and heated to 550 ℃ again at a fixed heating rate of 5 ℃/min, the temperature is maintained for 2h, and g-CN is obtained after cooling.
(2) The CoAl LDH/g-CN heterojunction is synthesized by a solvothermal reaction in one step: first, 1.25mmol of Co (NO) was weighed 3 ) 2 ·6H 2 O，1.25mmol Al(NO 3 ) 3 ·9H 2 O and 0.2g of-CN are dispersed in 20mL of deionized water and stirred for 30min; then, 5mmol of urea and 1.5mmol of NH were added 4 F, adding the mixture into the solution, and stirring for 10min. Finally, the solution is transferred to25mL of a Teflon lined reactor was held in an oven at 80 ℃ for 24h. The prepared sample was centrifuged, washed repeatedly with deionized water and ethanol, and dried in a vacuum oven at 60 ℃ for 12h to obtain CoAl LDH/g-CN.
(3)Al 2 S 3 the/CoAl LDH/g-CN composite material is synthesized by a one-step solvothermal method: weighing a certain amount of CoAl LDH/g-CN and thioacetamide, dispersing in deionized water, and continuously stirring; after the stirring is finished, transferring the solution into a polytetrafluoroethylene-lined reaction kettle and keeping the solution in an oven for reaction at a certain temperature for a certain time. Centrifuging the prepared sample, repeatedly washing with deionized water and ethanol, and drying in a vacuum oven to obtain Al 2 S 3 /CoAl LDH/g-CN。
(4) Preparation of photoelectrochemical aptamer sensor: firstly, an ITO conductive glass pretreatment process is carried out, wherein ITO conductive glass is sequentially and ultrasonically cleaned in deionized water and ethanol for half an hour, and then is repeatedly washed by deionized water. And then putting the conductive glass into 0.1mol/L NaOH aqueous solution, boiling the conductive glass, keeping the boiling for 30min, washing the conductive glass with deionized water and drying the conductive glass for later use. Preparation of 1mg/mL Al 2 S 3 Putting the aqueous solution of/CoAl LDH/g-CN into an ultrasonic machine for ultrasonic dispersion to obtain stable suspension; then, 50 μ L of suspension liquid is dripped on the pretreated ITO conductive glass and dried for 30min under an infrared lamp, and the prepared modified electrode is marked as Al 2 S 3 /CoAl LDH/g-CN-ITO. Next, 20. Mu.L of enrofloxacin aptamer was pipetted onto Al 2 S 3 Drying the surface of a/CoAl LDH/g-CN-ITO electrode at room temperature, washing with deionized water, and continuously airing at room temperature to obtain the photoelectrochemical aptamer sensor marked as Al 2 S 3 /CoAl LDH/g-CN-aptamer-ITO。
(5) Photoelectrochemical detection methods and conditions: electrochemical experiments using the CHI660E electrochemical workstation (shanghai chenhua instruments ltd), using a traditional three-electrode system: the modified electrode is a working electrode, the platinum wire electrode is a counter electrode, and the saturated Ag/AgCl electrode is a reference electrode. The excitation light source was a 300W xenon lamp (PLS-SXE 300, beijing Pofely Tech Co., ltd.). The electrochemical experiments are carried out at room temperature and phosphorusAcid salt buffer solution (0.1 mol/L, pH = 7.0) without any bias applied. EIS experiments in the presence of 5mmol/L Fe (CN) 6 3-/4- And 0.1mol/L KCl in a phosphate buffer solution (0.1 mol/L, pH = 7.0), with a frequency ranging from 0.01Hz to 10kHz, an initial potential of 0.24V, and an AC amplitude of 5mV.
Example 3:
(1) The g-CN powder is prepared by adopting a two-step calcination method: weighing 4.0g of urea, putting the urea into a 10mL crucible, then putting the crucible into a muffle furnace, and calcining at 550 ℃, wherein the heating rate is 5 ℃/min, and the calcining time is 2h; then, the cooled sample was ground to a powder and heated again to 550 ℃ at a fixed temperature rise rate of 5 ℃/min for 2h, and g-CN was obtained after cooling.
(2) The NiAl LDH/g-CN heterojunction is synthesized by a solvothermal reaction in one step: first, 1.5mmol of Co (NO) was weighed 3 ) 2 ·6H 2 O，0.5mmol Al(NO 3 ) 3 ·9H 2 Dispersing O and a certain content of g-CN in 20mL of deionized water, and stirring for 30min; then, urea and NH are mixed 4 F, adding the mixture into the solution, and stirring for 10min. Finally, the solution was transferred to a 25mL Teflon lined reactor and held in an oven at 120 ℃ for 24h. And centrifuging the prepared sample, repeatedly washing the sample with deionized water and ethanol, and drying the sample in a vacuum oven at 60 ℃ for 12 hours to obtain NiAl LDH/g-CN.
(3) The NiS/NiAl LDH/g-CN composite material is synthesized by a one-step solvothermal method: weighing a certain amount of NiAl LDH/g-CN and thiourea, dispersing in deionized water, and continuously stirring; after the stirring is finished, transferring the solution into a polytetrafluoroethylene-lined reaction kettle and keeping the solution in an oven for reaction at a certain temperature for a certain time. And centrifuging the prepared sample, repeatedly washing the sample by using deionized water and ethanol, and drying the sample in a vacuum oven to obtain NiS/NiAl LDH/g-CN.
(4) Preparation of photoelectrochemical aptamer sensor: firstly, an ITO conductive glass pretreatment process is carried out, wherein ITO conductive glass is sequentially and ultrasonically cleaned in deionized water and ethanol for half an hour, and then is repeatedly washed by deionized water. Then putting the conductive glass into 0.1mol/L NaOH aqueous solution, boiling the conductive glass, keeping the conductive glass for 30min, and usingAnd cleaning with deionized water and drying for later use. Preparation of 1mg/mL Al 2 S 3 Placing the aqueous solution of/CoAl LDH/g-CN into an ultrasonic machine for ultrasonic dispersion to obtain stable suspension; then, the suspension liquid is taken out and coated on the pretreated ITO conductive glass, and the ITO conductive glass is dried for 30min under an infrared lamp, and the prepared modified electrode is marked as NiS/NiAl LDH/g-CN-ITO. And then, transferring the enrofloxacin aptamer by using a liquid transfer gun, dripping the enrofloxacin aptamer on the surface of the NiS/NiAl LDH/g-CN-ITO electrode, drying at room temperature, washing with deionized water, and continuously airing at room temperature to obtain the photoelectrochemical aptamer sensor which is recorded as NiS/NiAl LDH/g-CN-aptamer-ITO.
(5) Photoelectrochemical detection methods and conditions: electrochemical experiments using the CHI660E electrochemical workstation (shanghai chenhua instruments ltd), using a traditional three-electrode system: the modified electrode is a working electrode, the platinum wire electrode is a counter electrode, and the saturated Ag/AgCl electrode is a reference electrode. The excitation light source was a 300W xenon lamp (PLS-SXE 300, beijing Pofely Tech Co., ltd.). The electrochemical experiments were all performed in phosphate buffered solution (0.1 mol/L, pH = 7.0) at room temperature without any bias applied. EIS experiments in the presence of 5mmol/L Fe (CN) 6 3-/4- And 0.1mol/L KCl in a phosphate buffer solution (0.1 mol/L, pH = 7.0), with a frequency ranging from 0.01Hz to 10kHz, an initial potential of 0.24V, and an AC amplitude of 5mV.
Example 4:
(1) The preparation of g-CN powder adopts a two-step calcination method: weighing 4.0g of urea, putting the urea into a 10mL crucible, then putting the crucible into a muffle furnace, and calcining at 550 ℃, wherein the heating rate is 5 ℃/min, and the calcining time is 2h; then, the cooled sample was ground to a powder and heated again to 550 ℃ at a fixed temperature rise rate of 5 ℃/min for 2h, and g-CN was obtained after cooling.
(2) The CoFe LDH/g-CN heterojunction is synthesized by a solvothermal reaction in one step: firstly, a certain molar amount of Co (NO) is weighed 3 ) 2 ·6H 2 O，Fe(NO 3 ) 3 ·9H 2 Dispersing O and g-CN in deionized water, and stirring until the O and the g-CN are dissolved; then, urea and NH are mixed 4 F was added to the solution with constant stirring. Finally, the solution is transferred to a polytetrafluoroethylene lining for reactionIn the kettle, the hydrothermal reaction is kept in an oven for a certain temperature and time. The prepared sample was centrifuged, washed repeatedly with deionized water and ethanol, and dried in a vacuum oven to obtain CoFe LDH/g-CN.
(3) The CoS/CoFe LDH/g-CN composite material is synthesized by a one-step solvothermal method: weighing a certain amount of CoFe LDH/g-CN and thiourea, dispersing in deionized water, and continuously stirring; after the stirring is finished, transferring the solution into a polytetrafluoroethylene-lined reaction kettle and keeping the solution in an oven for reaction at a certain temperature for a certain time. The prepared samples were centrifuged and washed repeatedly with deionized water and ethanol and dried in an oven to give CoS/CoFe LDH/g-CN.
(4) Preparation of photoelectrochemical aptamer sensor: firstly, an ITO conductive glass pretreatment process is carried out, wherein ITO conductive glass is sequentially and ultrasonically cleaned in deionized water and ethanol for half an hour, and then is repeatedly washed by deionized water. And then putting the conductive glass into 0.1mol/L NaOH aqueous solution, boiling the conductive glass, keeping the boiling for 30min, washing the conductive glass by using deionized water and drying the conductive glass for later use. Preparing an aqueous solution of CoS/CoFe LDH/g-CN with a certain concentration, and putting the aqueous solution into an ultrasonic machine for ultrasonic dispersion to obtain a stable suspension; then, the suspension liquid is taken out and coated on the pretreated ITO conductive glass, and the ITO conductive glass is dried under an infrared lamp, and the prepared modified electrode is marked as CoS/CoFe LDH/g-CN. And then, transferring the enrofloxacin aptamer by using a liquid transfer gun, dripping the enrofloxacin aptamer on the surface of a CoS/CoFe LDH/g-CN-ITO electrode, drying at room temperature, washing with deionized water, and continuously airing at room temperature to obtain the photoelectrochemical aptamer sensor which is marked as CoS/CoFe LDH/g-CN-aptamer-ITO.
(5) Photoelectrochemical detection methods and conditions: electrochemical experiments used the CHI660E electrochemical workstation (shanghai chen instruments ltd) with a traditional three-electrode system: the modified electrode is a working electrode, the platinum wire electrode is a counter electrode, and the saturated Ag/AgCl electrode is a reference electrode. The excitation light source was a 300W xenon lamp (PLS-SXE 300, beijing Pofely Tech Co., ltd.). Electrochemical experiments were all performed in phosphate buffered solution (0.1 mol/L, pH = 7.0) at room temperature without any bias applied. EIS experiments in the presence of 5mmol/L Fe (CN) 6 3-/4- And 0.1mol/L KCl in phosphate buffer solution (0.1 mol/L, pH = 7)0) at a frequency in the range of 0.01Hz to 10kHz, an initial potential of 0.24V and an AC amplitude of 5mV.
FIG. 1 shows NiS 2 X-ray diffraction (XRD) pattern of/NiFe LDH/g-CN composite material, wherein a is g-CN, b is NiFe LDH, c is NiFe LDH/g-CN, d is NiS 2 NiFe LDH/g-CN. Characteristic peaks of g-CN and NiFe LDH are respectively found from a and b; c, finding that the heterojunction shows characteristic peaks of existing g-CN and NiFe LDH; d shows g-CN, niFe LDH and NiS 2 The coexistence of the ternary substances indicates that the NiFe LDH/g-CN composite material is successfully vulcanized.
FIG. 2 shows NiS 2 And (3) Transmission Electron Microscope (TEM) and high power transmission electron microscope (HRTEM) images of the/NiFe LDH/g-CN composite material, wherein a is the TEM and b is the HRTEM image. As can be seen from FIG. 2a, the flaky g-CN successfully wraps the flower-like NiFe LDH; niS can be determined by the lattice spacing in FIG. 2b 2 Successfully grow on NiFe LDH/g-CN.
FIG. 3 shows NiS 2 Solid ultraviolet Diffuse Reflectance (DRS) diagram of the/NiFe LDH/g-CN composite material. Wherein a is g-CN, b is NiFe LDH, c is NiFe LDH/g-CN, d is NiS 2 NiFe LDH/g-CN. Through the synergistic introduction of NiFe LDH and sulfide cocatalyst, the composite material has stronger absorption in visible light and ultraviolet light regions, and is beneficial to generating more photo-generated electron-hole pairs, so that the composite material has better photoelectric property.
FIG. 4 shows NiS 2 Electrochemical Impedance (EIS) diagram of/NiFe LDH/g-CN composite material. Wherein a is g-CN-ITO, b is NiFe LDH/g-CN-ITO, and c is NiS 2 NiFe LDH/g-CN-ITO. The resistance value of the material prepared by the invention is detected by carrying out alternating current impedance on the working electrode, the capability of the composite material for transferring electrons is further researched, the smaller the radius is, the stronger the capability of the composite material for transferring electrons is, and as can be seen from figure 4, niS 2 The charge transfer capability of/NiFe LDH/g-CN-ITO is strongest, and the second is NiFe LDH/g-CN-ITO, because the NiFe LDH is introduced to form a heterojunction, and in addition, because NiS 2 As a cocatalyst for conducting electrons, the composite material promotes the efficient transmission of photo-generated charges, and has better photoelectric property.
FIG. 5 shows NiS 2 The photoelectromogram of the/NiFe LDH/g-CN composite material is shown in the specification, wherein a is g-CN-ITO, b is NiFe LDH/g-CN-ITO, and c is NiS 2 NiFe LDH/g-CN-ITO, d is NiS 2 NiFe LDH/g-CN-aptamer-ITO, e is NiS 2 NiFe LDH/g-CN-aptamer-ENR-ITO. Under the irradiation of light, the electrodes made of different materials respond to light differently, and the generated photocurrent intensities are also different. Therefore, different responses of different materials to light can be explained according to different light currents generated by different working electrodes, and the stronger the light current is, the higher the separation efficiency of the photo-generated electrons and holes of the working electrodes under illumination is. As can be seen from fig. 5, the heterojunction prepared by the present invention shows the highest photocurrent value, which indicates that the layered double hydroxide with visible light response is introduced to construct the heterojunction, and inhibit the recombination of carriers, and simultaneously, the sulfide is used as a promoter to further promote the separation/transfer of the photo-generated electrons and holes, so that the composite has better photoelectric properties, and this result is consistent with the EIS diagram result. The results show that the composite material is expected to be used for constructing a photoelectrochemical aptamer sensor and realizing efficient ENR detection.
FIG. 6 shows NiS 2 The photoelectric signal response diagram of ENR detected by NiFe LDH/g-CN-aptamer-ITO is shown in the specification, wherein a is a photoelectric current diagram obtained by detecting ENR with different concentrations, the ENR concentrations are respectively 1fmol/L,10fmol/L,0.1pmol/L,1pmol/L,10pmol/L,0.1nmol/L,1nmol/L,10nmol/L and 100nmol/L, and b is a drawn linear relation diagram of ENR concentration-photocurrent increment. As can be seen from FIG. 6a, as the ENR concentration increases, the photocurrent signal of the sensor gradually increases and shows a certain linear relationship, the linear range is 1fmol/L-100nmol/L, and the linear equation is I (μ A) = 0.5687 +0.07693log (C) ENR/pmol/L )(R 2 ＝0.992,C OFL 1fmol/L-100 nmol/L), the limit of detection is 0.34fmol/L.
Claims (10)
1. A preparation method of a photoelectrochemical aptamer sensor for detecting enrofloxacin is characterized by comprising the following steps:
(1) Preparation of a sulphided LDH/g-CN composite by solvothermal method:
firstly, weighing a certain amount of melamine or urea, and obtaining g-CN by a two-step calcination method;
then, weighing a certain amount of divalent metal salt, trivalent metal salt and g-CN into a reaction kettle with a polytetrafluoroethylene lining, adding deionized water, and fully dissolving; adding a certain amount of urea and ammonium fluoride into the solution, continuously stirring until the urea and the ammonium fluoride are uniformly mixed, carrying out constant-temperature hydrothermal reaction, taking out the reaction kettle after the reaction is finished, and naturally cooling to room temperature; centrifuging the sample, washing with alcohol and water for several times, and drying in a vacuum oven at constant temperature to obtain LDH/g-CN;
then, weighing a certain amount of LDH/g-CN and sulfur source in a reaction kettle with a polytetrafluoroethylene lining, adding deionized water, continuously stirring, putting the high-pressure kettle in an oven for hydrothermal reaction, removing the reaction kettle after the reaction is finished, and naturally cooling to room temperature; centrifuging to collect a sample, washing with water and alcohol for several times, and drying to obtain LDH sulfide/g-CN;
the sulfur source is thioacetamide or thiourea;
(2) Preparation of LDH sulfide/g-CN-ITO electrode:
dispersing a certain amount of LDH/g-CN sulfide composite material in deionized water, and performing ultrasonic treatment to uniformly disperse the LDH/g-CN sulfide composite material to obtain a stable suspension; secondly, the suspended liquid is dripped on the surface of ITO conductive glass, and after drying under an infrared lamp, the suspended liquid is washed by deionized water and dried at room temperature, so that an LDH sulfide/g-CN-ITO electrode is obtained;
(3) Preparing a vulcanized LDH/g-CN-aptamer-ITO electrode:
and (3) transferring a certain amount of enrofloxacin ENR aptamer by using a liquid transfer gun, dripping the enrofloxacin ENR aptamer on the surface of the LDH sulfide/g-CN-ITO electrode prepared in the step (2), naturally drying at room temperature, washing with deionized water, and airing at room temperature to obtain the photoelectrochemical aptamer sensor, namely the LDH sulfide/g-CN-aptamer-ITO.
2. The preparation method according to claim 1, wherein in the step (1), the temperatures of the two-step calcination are both 400 to 700 ℃, the calcination rates of the first step and the second step are 2 to 5 ℃/min and 1 to 2 ℃/min respectively, and the calcination times of the first step and the second step are 2 to 4 hours and 2 to 8 hours respectively.
3. The preparation method according to claim 1, wherein in the step (1), the divalent metal salt, the trivalent metal salt, g-CN, deionized water, urea and ammonium fluoride are used in a ratio of 0.25 to 1.25mmol: 0.04-1.25 mmol: 0.08-0.2 g:20mL of: 4-5 mmol: 0.5-1.5 mmol, the temperature of the constant temperature hydrothermal reaction is 80-140 ℃, and the time is 15-24 h; the temperature of the vacuum drying oven is 60 ℃, and the drying time is 12h.
4. The method according to claim 1, wherein in the step (1), the ratio of the LDH/g-CN to the sulfur source is 0.05-0.1 g: 0.03-0.12 mmol, and the hydrothermal reaction temperature of the autoclave in a baking oven is 80-140 ℃ for 1-4 h.
5. The method according to claim 1, wherein in the step (2), the suspension is used in an amount of 50. Mu.L at a concentration of 1.0 mg/mL.
6. The preparation method according to claim 1, wherein in the step (3), the concentration and the dosage ratio of the enrofloxacin aptamer are 0.5-2.0 μmol/L:20 mu L of the solution; the sequence of the enrofloxacin aptamer is 5.
7. Use of the photoelectrochemical aptamer sensor for detecting enrofloxacin, prepared by the preparation method according to any one of claims 1 to 6, for detecting enrofloxacin.
8. Use according to claim 7, comprising the following steps:
step 1, measuring a standard curve: dripping a series of enrofloxacin with known concentration on the surface of an LDH sulfide/g-CN-aptamer-ITO electrode, naturally drying at room temperature, washing with deionized water, and then airing at room temperature to obtain the LDH sulfide/g-CN-aptamer-ENR-ITO electrode;
taking the prepared LDH/g-CN-aptamer-ENR-ITO electrode as a working electrode, ag/AgCl as a reference electrode, pt as a counter electrode, and a phosphate buffer solution as an electrolyte, and measuring the photocurrent response value of the electrode under zero-volt bias to obtain a series of concentration-photocurrent corresponding relations, thereby obtaining a standard curve of enrofloxacin;
step 2, taking a certain amount of liquid to be measured to be dripped on the surface of an LDH/g-CN-aptamer-ITO electrode, naturally drying at room temperature, washing with deionized water, and then airing at room temperature, wherein the prepared electrode is marked as LDH/g-CN-aptamer-ENR-ITO;
and measuring the photocurrent response value of the prepared LDH/g-CN-aptamer-ENR-ITO electrode as a working electrode, ag/AgCl as a reference electrode, pt as a counter electrode and phosphate buffer solution as electrolyte under zero-volt bias, and substituting the photocurrent value into a standard curve for conversion to obtain the ENR concentration in the detection solution.
9. The use according to claim 8, wherein in step 1, the ENR is used in an amount and concentration ratio of 20 μ L: 1fmol/L-100 nmol/L; the phosphoric acid buffer solution was prepared by preparing 0.1mol/L sodium dihydrogen phosphate and disodium hydrogen phosphate to adjust the pH to 7.0, and the concentration was 0.1mol/L.
10. The use according to claim 8, wherein in step 2, the phosphate buffer solution is prepared by preparing 0.1mol/L sodium dihydrogen phosphate and disodium hydrogen phosphate to have a pH of 7.0 and a concentration of 0.1mol/L.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011067812.XA CN112461904B (en) | 2020-10-07 | 2020-10-07 | Preparation method and application of photoelectrochemical aptamer sensor for detecting enrofloxacin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011067812.XA CN112461904B (en) | 2020-10-07 | 2020-10-07 | Preparation method and application of photoelectrochemical aptamer sensor for detecting enrofloxacin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112461904A CN112461904A (en) | 2021-03-09 |
| CN112461904B true CN112461904B (en) | 2023-01-17 |
Family
ID=74833498
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011067812.XA Active CN112461904B (en) | 2020-10-07 | 2020-10-07 | Preparation method and application of photoelectrochemical aptamer sensor for detecting enrofloxacin |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112461904B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114487058B (en) * | 2021-12-10 | 2023-06-09 | 江苏大学 | Preparation method and application of photoelectrochemical aptamer sensor for detecting fluoroquinolone antibiotics |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105040025A (en) * | 2015-05-12 | 2015-11-11 | 北京化工大学 | Double metal hydroxide-composited porous bismuth vanadate photo-electrode and preparation method thereof |
| CN107268021A (en) * | 2017-06-26 | 2017-10-20 | 河南大学 | A kind of NiCoAl LDH modifications di-iron trioxide complex light anode material and its preparation method and application |
| CN109115851A (en) * | 2018-08-17 | 2019-01-01 | 江苏大学 | A kind of preparation method and purposes of the optical electro-chemistry aptamer sensor detecting bisphenol-A |
| CN109507255A (en) * | 2018-10-10 | 2019-03-22 | 江苏大学 | A kind of Preparation method and use of bismuth/carbonitride photoelectric material |
| CN111044586A (en) * | 2019-11-06 | 2020-04-21 | 江苏大学 | Preparation method of bismuth-doped polymeric carbon nitride nanocomposite material containing carbon defects |
-
2020
- 2020-10-07 CN CN202011067812.XA patent/CN112461904B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105040025A (en) * | 2015-05-12 | 2015-11-11 | 北京化工大学 | Double metal hydroxide-composited porous bismuth vanadate photo-electrode and preparation method thereof |
| CN107268021A (en) * | 2017-06-26 | 2017-10-20 | 河南大学 | A kind of NiCoAl LDH modifications di-iron trioxide complex light anode material and its preparation method and application |
| CN109115851A (en) * | 2018-08-17 | 2019-01-01 | 江苏大学 | A kind of preparation method and purposes of the optical electro-chemistry aptamer sensor detecting bisphenol-A |
| CN109507255A (en) * | 2018-10-10 | 2019-03-22 | 江苏大学 | A kind of Preparation method and use of bismuth/carbonitride photoelectric material |
| CN111044586A (en) * | 2019-11-06 | 2020-04-21 | 江苏大学 | Preparation method of bismuth-doped polymeric carbon nitride nanocomposite material containing carbon defects |
Non-Patent Citations (1)
| Title |
|---|
| Layered double hydroxides decorated graphic carbon nitride film as efficient photoanodes for photoelectrochemical water splitting;Xiaoli Fan et al;《Catalysis Today》;20190115;第335卷;423-428 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112461904A (en) | 2021-03-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109507255B (en) | Preparation method and application of bismuth/carbon nitride photoelectric material | |
| CN108845009B (en) | A kind of optical electro-chemistry aptamer sensor and its preparation method and application | |
| CN110618272B (en) | Preparation method and application of mercury ion fluorescence/electrochemical sensor | |
| CN112683971B (en) | Chloramphenicol photoelectrochemical aptamer sensor and preparation method and application thereof | |
| CN112461904B (en) | Preparation method and application of photoelectrochemical aptamer sensor for detecting enrofloxacin | |
| Dong et al. | Photoelectrochemical response to glutathione in Au-decorated ZnO nanorod array | |
| CN108562633B (en) | Photoelectrochemical sensor for detecting sulfadimethoxine and detection method thereof | |
| Ju et al. | Amplified photoelectrochemical DNA biosensor based on a CdS quantum dot/WS 2 nanosheet heterojunction and hybridization chain reaction-mediated enzymatic hydrolysis | |
| CN114487395A (en) | Construction method and use of nano antibody photoelectrochemical immunosensor for detecting SARS-CoV-2S protein | |
| CN112763438A (en) | Application of carbon dot peroxidase CDs @ NC in detection of D-alanine and D-proline | |
| Wang et al. | Photoelectrochemical biosensor for 5-formylcytosine deoxyribonucleoside detection based on BiIO4-WS2/CuO ternary heterojunction | |
| CN111912887B (en) | Preparation method of photoelectrochemical ofloxacin aptamer sensor based on hydrotalcite/graphite-like phase carbon nitride heterojunction | |
| Yang et al. | A disposable and sensitive non-enzymatic glucose sensor based on a 3D-Mn-doped NiO nanoflower-modified flexible electrode | |
| CN113237934B (en) | Chiral silver sulfide quantum dot/few-layer carbon nitride compound capable of being used for electrochemiluminescence chiral recognition and preparation method thereof | |
| CN108459066B (en) | Photoelectrochemistry biological immunosensor, preparation method thereof and application of photoelectrochemistry biological immunosensor in detection of specific base sequence | |
| CN110927233A (en) | Electrochemical sensor for detecting epinephrine and preparation method and application thereof | |
| CN107328834B (en) | Composite material modified electrode for detecting lead ions in livestock and poultry drinking water and preparation method thereof | |
| CN109115851A (en) | A kind of preparation method and purposes of the optical electro-chemistry aptamer sensor detecting bisphenol-A | |
| CN110763850B (en) | Method for detecting 17 beta-estradiol by non-labeling homogeneous cathode photoelectrochemistry | |
| CN109813774B (en) | Method for detecting clenbuterol by photo-induced electrochemical sensor | |
| CN116297748A (en) | Preparation method and application of transition metal nitride modified carbon nitride acceptor-donor type photoelectrode | |
| CN115656495A (en) | Preparation method and application of ternary heterojunction composite material photoelectrochemical immunosensor | |
| CN114487058B (en) | Preparation method and application of photoelectrochemical aptamer sensor for detecting fluoroquinolone antibiotics | |
| CN109433227A (en) | Preparation method, Photoelectrochemistrbiosensor biosensor and its application of CdS@GR-CoOOH nanocomposite | |
| CN108490054B (en) | Photoelectrochemical DNA sensor for detecting DNA sequence and preparation method and detection method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |