CN112858407B - Electrochemical sensor for detecting ciprofloxacin and detection method thereof - Google Patents
Electrochemical sensor for detecting ciprofloxacin and detection method thereof Download PDFInfo
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Abstract
The invention discloses an electrochemical sensor for detecting ciprofloxacin and a detection method thereof, and belongs to the technical field of food safety detection. The electrochemical sensor takes an electrode modified by a COF @ CB @ MPDA composite material as a working electrode; the COF @ CB @ MPDA composite material is prepared by the following method: dispersing COF and CB into double distilled water to obtain a mixed solution; then ciprofloxacin and dopamine were mixed at a molar ratio of 1: (9-12) adding the mixture into the mixed solution, uniformly dispersing, adding a Tris-HCl (pH 8.5) solution, stirring at room temperature for reaction for 10-14h, and washing and drying the obtained product to obtain the COF @ CB @ MPDA composite material. The minimum detection limit of the electrochemical sensor for ciprofloxacin is 9.46 mug/kg, so that the detection requirement can be met; the pretreatment and analysis time is respectively shortened by 48 minutes and 10 minutes compared with the traditional detection method, and the method is suitable for quickly detecting the ciprofloxacin.
Description
Technical Field
The invention relates to the technical field of food safety detection, in particular to an electrochemical sensor for detecting ciprofloxacin and a detection method thereof.
Background
Ciprofloxacin (CIP) belongs to the third-generation fluoroquinolone antibacterial drugs, and the structural formula of ciprofloxacin is as follows:
ciprofloxacin has broad-spectrum antibacterial activity and has good effect on gram-positive bacteria and gram-negative bacteria. Thus, ciprofloxacin is commonly used to treat digestive and respiratory infections as well as urinary tract infections. Ciprofloxacin can inhibit bacterial DNA helicase, prevent bacterial replication and quickly reduce bacterial reproduction.
Ciprofloxacin, however, sometimes causes allergic reactions, phlebitis, gastrointestinal reactions and central nervous system reactions in humans. The Ministry of agriculture of the people's republic of China stipulates that the maximum allowable residual limit of ciprofloxacin and norfloxacin in animal-derived food is 100 mug/kg.
At present, the detection method of ciprofloxacin in related food at home and abroad adopts a liquid chromatography or a method of combining liquid chromatography, gas chromatography and mass spectrum for qualitative and quantitative detection. However, the devices used in the above detection methods are expensive, the analysis time is long, and complicated sample pretreatment techniques are required; therefore, the research and development of a rapid, accurate and sensitive ciprofloxacin detection method has important significance.
As is clear from the structure of ciprofloxacin, ciprofloxacin having a piperazine ring at the 7-position can be oxidized, indicating that ciprofloxacin is an electrochemically active substance and therefore can be directly measured electrochemically. Lida Fotouhi and Mahnaz Alahiari realize direct electrochemical detection of ciprofloxacin by using multi-walled carbon nanotube modified electrode, and the detection linear range of ciprofloxacin concentration under the optimal condition is 40-1000 mu mol L-1The detection limit is 6 mu mol L-1And the content of the ciprofloxacin in two actual samples, namely a urine sample and a serum sample, is detected. Nizam Diab et al have realized on the surface of DNA modified electrode direct electrochemical detection to ciprofloxacin, the experiment shows, compared with naked glassy carbon electrode, because the interaction of ciprofloxacin and DNA makes the irreversible oxidation peak of ciprofloxacin on the surface of DNA modified electrode greatly strengthen, the interaction of both can use electrochemical scanning method of cyclic voltammetry to study, and measured the binding constant of both interactions, ciprofloxacin detection linear range under the optimum condition is 1.0-10 μmol L-1The detection limit is 0.117 mu mol L-1. Al A. Ensafi et al uses MgFe2O4The method for modifying the glassy carbon electrode by the two nano materials of the nano particles and the carbon nano tubes is used for directly and electrochemically detecting the ciprofloxacin content, and characterizing the morphology and electrochemical characteristics of the materials by means of XRD, TEM, cyclic voltammetry and the like. Under the optimal condition, the linear range of ciprofloxacin detection is 0.10-1000 mu mol L-1The detection limit and the quantitative detection limit are respectively 0.01 mu mol L-1And 0.08. mu. mol L-1The method is also used for detecting ciprofloxacin in several samples such as tablets, urine samples and plasma samples.
However, according to the principle of redox reaction, all compounds having a structure similar to that of ciprofloxacin can exhibit an oxidation peak at the same potential. The above reported methods cannot exclude the influence of interferents if a structural analog of ciprofloxacin is present in the matrix of the sample to be tested, thereby deteriorating the accuracy of the test results. In addition, the electrode modification materials and synthesis processes used in the above reported methods are complicated and require high-temperature heating.
Disclosure of Invention
In view of the prior art, the invention aims to provide an electrochemical sensor for detecting ciprofloxacin and a detection method thereof. The electrochemical sensor can realize rapid and sensitive detection of ciprofloxacin, has simple sample pretreatment, high detection sensitivity and short analysis time, and is suitable for rapid and sensitive detection of ciprofloxacin in various foods.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides an electrochemical sensor for detecting ciprofloxacin, which takes an electrode modified by a COF @ CB @ MPDA composite material as a working electrode; the COF @ CB @ MPDA composite material is prepared by the following method:
dispersing a Covalent Organic Framework (COF) material and Carbon Black (CB) into double distilled water to obtain a mixed solution; then ciprofloxacin and dopamine were mixed at a molar ratio of 1: (9-12) adding the mixture into the mixed solution, uniformly dispersing, adding a Tris-HCl solution, stirring at room temperature for reaction for 10-14h, and washing and drying the obtained product to obtain the non-eluted COF @ CB @ MPDA composite material; and finally, carrying out ultrasonic washing on the un-eluted COF @ CB @ MPDA composite material for 4h by alternately using methanol and double distilled water to remove template molecules, thus obtaining the eluted COF @ CB @ MPDA composite material.
Preferably, the Tris-HCl solution has a pH of 8.5.
Preferably, the COF is prepared by the following method:
mixing 1,3, 5-tri (4-aminophenyl) benzene and 2, 5-divinyl-1, 4-benzene dicarboxaldehyde according to the mass ratio of (0.02-0.03) g: (0.02-0.03) g of the mixture is mixed and dispersed into an acetonitrile solution, ultrasonic treatment is carried out, then an acetic acid solution is dropwise added, and the mixture is shaken and uniformly mixed to obtain a mixed solution; and standing the mixed solution at room temperature, centrifuging, washing and drying the obtained product to obtain the COF.
Preferably, the method for modifying the electrode by using the COF @ CB @ MPDA composite material comprises the following steps:
the COF @ CB @ MPDA composite material is dropwise coated on the surface of a bare glassy carbon electrode and dried to obtain a modified COF @ CB @ MPDA/GCE electrode; namely the working electrode.
More preferably, the concentration of the COF @ CB @ MPDA dispersion is 1-3 mg/mL.
Further, the electrochemical sensor further includes: a reference electrode and an auxiliary electrode.
Preferably, the reference electrode is a saturated calomel electrode; the auxiliary electrode is a platinum electrode.
In a second aspect of the invention, there is provided the use of the electrochemical sensor described above in the detection of ciprofloxacin.
In a third aspect of the present invention, there is provided a method for detecting ciprofloxacin using the above electrochemical sensor, comprising the steps of:
(1) forming a three-electrode system by a working electrode, a reference electrode and an auxiliary electrode in an electrochemical sensor, immersing the working electrode into ciprofloxacin standard solutions with different concentrations for incubation in a potential window of 0.7-1.3V by using a differential pulse voltammetry method, and recording corresponding current values IP(ii) a Drawing a working curve by taking the concentration of the ciprofloxacin standard solution as an abscissa and the current value I as an ordinate;
(2) and (3) detecting the ciprofloxacin content in the pre-treated object to be detected by using the working curve drawn in the step (1).
Preferably, in the step (2), the pretreatment method of the analyte is: and repeatedly extracting the substance to be detected for 2-4 times by using acetonitrile vortex centrifugation, removing fat by using n-hexane, combining extracting solutions and drying by using nitrogen.
More preferably, the adding amount ratio of the substance to be detected to the acetonitrile is 1g (1-3) mL.
The invention has the beneficial effects that:
(1) according to the electrochemical sensor, an electrode modified by COF @ CB @ MPDA dispersion liquid is used as a working electrode, the electrochemical sensor capable of sensitively detecting ciprofloxacin is constructed, the COF @ CB @ MPDA composite material has a large specific surface area, the CB can obviously improve the conductivity of the composite material, the MPDA layer can realize the specific recognition of the electrochemical sensor on the ciprofloxacin, the interference of oxidation peaks of compounds with similar structures to the ciprofloxacin under the same potential is eliminated, and the detection accuracy is improved; moreover, the CB, the COF and the MPDA have a synergistic effect, and the oxidation peak current value of the ciprofloxacin can be obviously increased.
(2) The lowest detection limit of the electrochemical sensor for ciprofloxacin is 9.46 mug/kg; the MRL value of ciprofloxacin is specified to be 100 mug/kg in the national standard, so that the method can meet the detection requirement and can meet the detection requirement. Moreover, the pretreatment time and the analysis time of the method are respectively shortened by about 48 minutes and 10 minutes compared with the traditional detection method, and the method is suitable for quickly detecting the ciprofloxacin.
(3) The synthesis method of the electrode modification material is simple and can be completed at room temperature. Therefore, the electrochemical sensor prepared by the method is low in cost, simple in pretreatment, high in sensitivity, short in analysis time and simple in experimental operation, and is suitable for quickly detecting ciprofloxacin in various foods.
Compared with the conventional other methods for detecting ciprofloxacin, the method disclosed by the invention has the following advantages:
drawings
FIG. 1: a is a CV curve of COF @ CB @ MPDA/GCE of the invention in 1mM ciprofloxacin at different scanning rates; b is the relationship of the peak power at the log of the scan rate.
FIG. 2: a is a DPV curve of the COF @ CB @ MPDA/GCE ciprofloxacin solution with different pH values; b is a linear relationship between DPV reaction potential and PBS pH.
FIG. 3: DPV curves of GCE, MPDA/GCE, CB @ MPDA/GCE, COF @ MPDA/GCE, and CB @ COF @ MPDA/GCE in 50mM ciprofloxacin solution.
FIG. 4: detecting a ciprofloxacin standard curve by using an electrochemical sensor;
as can be seen from FIG. 4, the linear range of ciprofloxacin detection by this method is 1.0X 10-4-5.0×10-7mol/L, minimum detection limit of 9.5X 10-8mol/L(9.46μg/kg)。
FIG. 5 is a schematic view of: current values in 50mM ciprofloxacin, enoxacin, moxifloxacin and enrofloxacin for COF @ CB @ MPDA/GCE and COF @ CB @ NPDA/GCE.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
Description of terms:
the term "room temperature" as used herein means a temperature of 15 to 30 ℃.
As introduced in the background art, the conventional detection methods for ciprofloxacin in related food at home and abroad mostly adopt a liquid chromatography method or a method combining liquid chromatography, gas chromatography and mass spectrometry for qualitative and quantitative detection, but the detection methods have the disadvantages of expensive equipment, long analysis time and complex sample pretreatment technology; although the electrochemical method based on the oxidation-reduction reaction has high detection sensitivity, the compound with the similar structure to that of the ciprofloxacin can generate an oxidation peak under the same potential, so that the detection of the ciprofloxacin is interfered, and the accuracy and the specificity of the detection are reduced.
Based on the above, the invention aims to provide an electrochemical sensor capable of sensitively and specifically detecting ciprofloxacin and a detection method thereof.
In order to realize sensitive and specific ciprofloxacin detection, an electrode modified by COF @ CB @ MPDA dispersion liquid is used as a working electrode (COF @ CB @ MPDA/GCE) to construct an electrochemical sensor capable of sensitively detecting ciprofloxacin, wherein the COF @ CB @ MPDA composite material has a large specific surface area, the CB can remarkably improve the conductivity of the composite material, and the MPDA layer can realize specific recognition of the electrochemical sensor on ciprofloxacin; CB. The COF and the MPDA have a synergistic effect, and the oxidation peak current value of the ciprofloxacin can be obviously increased. A standard curve is established by utilizing the relation between the concentration of the ciprofloxacin and the current to realize the quantitative detection of the ciprofloxacin, so that a rapid detection method with high sensitivity to the ciprofloxacin is established. The method provided by the invention has the lowest detection limit of 9.46 mu g/kg for ciprofloxacin, and realizes high sensitivity and specificity detection for ciprofloxacin.
The CV curve of the working electrode (COF @ CB @ MPDA/GCE) of the invention at different scanning rates in 1mM ciprofloxacin and a linear plot of peak potential versus log of scanning rate. It can be seen from fig. 1(a) that the peak current increases with an increase in the scan rate, and the peak potential moves in the negative potential direction with an increase in the scan rate. The linear equation of the peak potential versus the log of the scan rate found in fig. 1 (B) is ep (v) 0.0485logV (Vs-1) + 1.28. According to the Lavirons equation:
wherein A is a constant related to the standard electrode potential; α is the transmission coefficient; n is the electron transfer number of the diffusion control process; r, T and F are the gas constant, temperature and Faraday constant, respectively. The slope of the resulting line should be 2.303 RT/(1-. alpha.) nF. N is calculated to be about 2.4 by the linear equation obtained. Therefore, it is presumed that the oxidation reaction of ciprofloxacin is a reaction involving 2 electrons.
According to the invention, the oxidation mechanism of ciprofloxacin is further explored by investigating the relation between the peak potential and the pH value of COF @ CB @ MPDA/GCE in 50mM ciprofloxacin solutions prepared at different pH values. FIG. 2(A) is a DPV curve of COF @ CB @ MPDA/GCE in 50mM ciprofloxacin solutions prepared at different pH values, and it can be seen that the peak potential value gradually moves towards a negative potential direction as the pH value gradually increases. The linear relationship between the two was found from the relationship between the peak potential and pH to be ep (v) 0.0593pH +1.3643 (fig. 2 (B)). However, the theoretical value of the linear dependence of Ep on pH is 59 mV. This result can indicate that the number of protons and electrons involved in the oxidation reaction in ciprofloxacin are equal. Combining the results obtained above, it is assumed that the oxidation reaction of ciprofloxacin is carried out by 2 electrons and 2 protons.
According to the structural formula of ciprofloxacin and the fact that oxidation reaction of ciprofloxacin is irreversible, oxidation reaction of ciprofloxacin is supposed to be oxidation from secondary amine in the structure to hydroxylamine derivative. The electrochemical reaction structural formula of ciprofloxacin is shown as follows:
figure 3 is a DPV curve of different modified electrodes in a 50mM ciprofloxacin solution. As is clear from the figure, the oxidation peak current value of ciprofloxacin increased after MPDA was surface-modified by GCE. The peak current values of CB @ MPDA/GCE and COF @ MPDA/GCE are significantly increased compared to MPDA/GCE, and the current value of CB @ MPDA/GCE is larger than that of COF @ MPDA/GCE. This is probably because CB not only has a large specific surface area but also can accelerate the electron transfer rate to make the current value increase more remarkable. While the current value of COF @ CB @ MPDA/GCE is the largest, which indicates that: CB. The COF and the MPDA have a synergistic effect, and the oxidation peak current value of the ciprofloxacin can be obviously increased.
In one embodiment of the invention, the method for modifying the electrode by the electrochemical sensor with COF @ CB @ MPDA dispersion is as follows:
and dripping 10 mu L of COF @ CB @ MPDA dispersion liquid with the concentration of 1-3 mg/mL on the surface of a bare glassy carbon electrode, and airing at room temperature to obtain the modified COF @ CB @ MPDA/GCE electrode.
As a preferred scheme, the COF @ CB @ MPDA composite material is prepared by the following method:
0.02-0.03 g of 1,3, 5-tri (4-aminophenyl) benzene and 0.02-0.03 g of 2, 5-divinyl-1, 4-benzenedicarboxaldehyde are dispersed in 5mL of acetonitrile, and then 0.5-1.0 mL of acetic acid solution (12mol/L) is slowly added dropwise to the mixed solution. The mixture was allowed to stand at room temperature for 72 h. And washing the obtained product with anhydrous tetrahydrofuran and anhydrous ethanol respectively, and then drying the product in vacuum at 80 ℃ for 12 hours to obtain the COF.
Because the synthesis of the molecular imprinting polymer for subsequent experiments is carried out in aqueous solution, in order to obtain better effect, the COF synthesized by the method has larger specific surface area and better dispersibility in water, and is more favorable for achieving the purpose of experiments.
COF and CB (10-50mg) are dispersed in 50mL double distilled water, then ciprofloxacin and dopamine are added into the mixed solution according to the molar ratio of (1: 9) - (1: 12), and the mixture is uniformly dispersed by ultrasonic. Then, 5mL of Tris-HCl (pH 8.5) solution is slowly added into the mixed solution, the mixture is stirred and reacted for 12 hours at room temperature, and the obtained product is washed and dried in vacuum to obtain the non-eluted COF @ CB @ MPDA composite material. And finally, ultrasonically washing the COF @ CB @ MPDA composite material for 4 hours by alternately using methanol and double distilled water to remove template molecules to obtain the eluted COF @ CB @ MPDA composite material.
In another embodiment of the present invention, a method for detecting ciprofloxacin using the electrochemical sensor of the present invention is provided, specifically as follows:
(1) respectively taking a saturated calomel electrode and a platinum electrode as a reference electrode and an auxiliary electrode, taking a COF @ CB @ MPDA modified electrode (COF @ CB @ MPDA/GCE) as a working electrode to form a three-electrode system, immersing the working electrode into ciprofloxacin standard solutions with different concentrations for incubation within a potential window of 0.7-1.3V by using a differential pulse voltammetry method, and recording corresponding current values IP。
(2) The concentration of ciprofloxacin standard solution was plotted on the abscissa and the current value on the ordinate, respectively, to obtain a working curve (fig. 4). Respectively calculating the contents of ciprofloxacin in the samples corresponding to different current values according to the following formula:
I(μA)＝0.2203C(μM)﹣0.0003
(3) adding acetonitrile solution into the analyte according to the weight-to-volume ratio (g/mL) of 1:1.5, performing vortex centrifugation for three times, repeatedly extracting, combining the extracting solutions, degreasing by using n-hexane, and drying by using nitrogen. Dissolving the residue obtained after nitrogen blowing by using 3mL of 0.2mol/L phosphate buffer solution, and filtering by using a 0.22 mu m filter membrane to obtain a sample extracting solution; and (3) replacing the ciprofloxacin standard solution with the sample extracting solution, repeating the operation in the step (2), and respectively calculating the ciprofloxacin content in the analyte from the standard curve according to the current value.
In order to make the technical solutions of the present application more clearly understood by those skilled in the art, the technical solutions of the present application will be described in detail below with reference to specific embodiments.
The test materials used in the examples of the present invention, which were not specifically described, were all those conventional in the art and commercially available. Wherein:
the COF @ CB @ MPDA composite material is prepared by the following method:
0.028g of 1,3, 5-tris (4-aminophenyl) benzene and 0.022g of 2, 5-divinyl-1, 4-benzenedicarboxaldehyde were dispersed in 5mL of acetonitrile, and then 0.7mL of an acetic acid solution (12mol/L) was slowly added dropwise to the above mixed solution. The mixture was allowed to stand at room temperature for 72 h. And washing the obtained product with anhydrous tetrahydrofuran and anhydrous ethanol respectively, and then drying the product in vacuum at 80 ℃ for 12 hours to obtain the COF.
Next, 15mg of COF and 15mg of CB were dispersed in 50mL of double distilled water to obtain a mixed solution; then 3.31mg of ciprofloxacin and 18.36mg of dopamine are added into the mixed solution, and the mixture is uniformly dispersed by ultrasonic. Then, 5mL of Tris-HCl (pH 8.5) solution is slowly added into the mixed solution, the mixture is stirred and reacted for 12 hours at room temperature, and the obtained product is washed and dried in vacuum to obtain the non-eluted COF @ CB @ MPDA composite material. And finally, ultrasonically washing the COF @ CB @ MPDA composite material for 4 hours by alternately using methanol and double distilled water to remove template molecules, so as to obtain the eluted COF @ CB @ MPDA composite material.
And dispersing the eluted COF @ CB @ MPDA composite material by using double distilled water to obtain a COF @ CB @ MPDA dispersion liquid.
Example 1:
1. modification of an electrochemical sensor electrode:
10 μ L of the COF @ CB @ MPDA dispersion at a concentration of 1.5mg/mL was dropwisely coated on the surface of a bare glassy carbon electrode, and dried at room temperature to obtain a modified electrode (COF @ CB @ MPDA/GCE).
2. The saturated calomel electrode and the platinum electrode are respectively used as referenceThe electrode COF @ CB @ MPDA/GCE obtained after modification of the experiment is used as a working electrode to form a three-electrode system, the working electrode is immersed into ciprofloxacin standard solutions with the concentrations of 0.5, 1, 5, 10, 20, 50 and 100 mu mol/L respectively to be incubated in a potential window of 0.7-1.3V by using a differential pulse voltammetry method, and corresponding current values I are recorded respectivelyP。
3. And drawing a working curve by taking the concentration of the ciprofloxacin standard solution as an abscissa and the current value as an ordinate. Calculating the contents of ciprofloxacin in the samples corresponding to different current values according to the following formula:
I(μA)＝0.2203C(μM)﹣0.0003
4. accurately weighing 10g of milk powder sample, adding 15mL of acetonitrile solution, performing vortex centrifugation, repeatedly extracting for three times, combining extracting solutions, degreasing by using n-hexane, and drying by using nitrogen. The residue obtained after nitrogen blowing was dissolved in 3mL of 0.2mol/L phosphate solution, and the solution was filtered through a 0.22 μm filter to obtain a sample extract.
5. Replacing the sample extract with standard solution, repeating step 2, and obtaining ciprofloxacin concentrations of 5.68 × 10 according to the above calculation formula-7And (5) calculating the ciprofloxacin content in the milk powder to be 56.4 mug/kg.
Example 2: the specificity of the detection method of the invention is as follows:
to investigate the specific recognition ability of COF @ CB @ MPDA for ciprofloxacin, in this example, three structural analogs of Enoxacin (Enoxacin), Moxifloxacin (Moxifloxacin) and Enrofloxacin (Enrofloxacin) at equal concentrations to ciprofloxacin were selected for selective experiments.
FIG. 5 is the peak current values for COF @ CB @ MPDA/GCE and COF @ CB @ NPDA/GCE in 50mM ciprofloxacin and an equivalent concentration of three structural analogs; compared with the synthesis of COF @ CB @ MPDA, the synthesis method of COF @ CB @ NPDA is the same as that of COF @ CB @ MPDA except that ciprofloxacin is not added. Calculated, the imprinting factors of COF @ CB @ MPDA/GCE on ciprofloxacin, enoxacin, moxifloxacin and enrofloxacin are 1.98, 1.19, 0.76 and 1.10 respectively. Therefore, COF @ CB @ MPDA/GCE has good specific recognition capability only for ciprofloxacin.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (5)
1. The electrochemical sensor for detecting ciprofloxacin is characterized in that an electrode modified by a COF @ CB @ MPDA composite material is used as a working electrode; the COF @ CB @ MPDA composite material is prepared by the following method:
dispersing a Covalent Organic Framework (COF) material and Carbon Black (CB) into double distilled water to obtain a mixed solution; then ciprofloxacin and dopamine were mixed at a molar ratio of 1: (9-12) adding the mixture into the mixed solution, uniformly dispersing, adding a Tris-HCl solution, stirring at room temperature for reaction for 10-14h, and washing and drying the obtained product to obtain the non-eluted COF @ CB @ MPDA composite material; washing the un-eluted COF @ CB @ MPDA composite material to remove template molecules to obtain the eluted COF @ CB @ MPDA composite material;
the COF is prepared by the following method:
mixing 1,3, 5-tri (4-aminophenyl) benzene and 2, 5-divinyl-1, 4-benzene dicarboxaldehyde according to the mass ratio of (0.02-0.03) g: (0.02-0.03), mixing and dispersing into an acetonitrile solution, performing ultrasonic treatment, then dropwise adding an acetic acid solution, and shaking and uniformly mixing to obtain a mixed solution; standing the mixed solution at room temperature, centrifuging, washing and drying the obtained product to obtain COF;
the method for modifying the electrode by the COF @ CB @ MPDA composite material comprises the following steps:
the COF @ CB @ MPDA composite material is dropwise coated on the surface of a bare glassy carbon electrode and dried to obtain a modified COF @ CB @ MPDA/GCE electrode; namely the working electrode.
2. The electrochemical sensor of claim 1, wherein the concentration of the COF @ CB @ MPDA dispersion is 1 to 3 mg/mL.
3. The electrochemical sensor of claim 1, further comprising: a reference electrode and an auxiliary electrode; the reference electrode is a saturated calomel electrode; the auxiliary electrode is a platinum electrode.
4. Use of an electrochemical sensor according to any one of claims 1 to 3 in the detection of ciprofloxacin.
5. A method for detecting ciprofloxacin using the electrochemical sensor according to any one of claims 1 to 3, comprising the steps of:
(1) forming a three-electrode system by a working electrode, a reference electrode and an auxiliary electrode in an electrochemical sensor, immersing the working electrode into ciprofloxacin standard solutions with different concentrations for incubation in a potential window of 0.7-1.3V by using a differential pulse voltammetry method, and recording corresponding current valuesI P (ii) a The concentration of ciprofloxacin standard solution is used as the abscissa and the current value is usedIDrawing a working curve for a vertical coordinate;
(2) detecting the content of ciprofloxacin in the pre-treated object to be detected by using the working curve drawn in the step (1);
in the step (2), the pretreatment method of the object to be tested comprises the following steps: repeatedly extracting the object to be detected for 2-4 times by using acetonitrile vortex centrifugation, removing fat by using n-hexane, combining extracting solutions and drying by using nitrogen; the adding amount ratio of the substance to be detected to the acetonitrile is 1g (1-3) mL.
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| CN102768232B (en) * | 2012-06-29 | 2014-05-07 | 南京医科大学 | Method for producing sildenafil molecular imprinting membrane electrochemical sensor (MIES) |
| CN103675057A (en) * | 2013-11-29 | 2014-03-26 | 中国广州分析测试中心 | Biosensor for organophosphorus pesticide rapid detection and detecting method thereof |
| CN106290513A (en) * | 2016-09-10 | 2017-01-04 | 上海大学 | Utilize the method that Graphene is combined the glass-carbon electrode mensuration ciprofloxacin that hematoxylin is modified |
| CN109001276B (en) * | 2018-09-21 | 2021-03-02 | 西北师范大学 | Construction and application of electrochemical sensor based on COFs (chemical-organic frameworks) material |
| CN109725036B (en) * | 2019-03-05 | 2019-10-25 | 山东农业大学 | Electrochemical sensor and its detection method a kind of while that detect sulphadiazine and paracetamol |
| CN110501402B (en) * | 2019-09-24 | 2020-04-28 | 山东农业大学 | Electrochemical sensor for ultrasensitive detection of sulfathiazole and detection method thereof |
| CN111307895B (en) * | 2020-04-03 | 2021-06-25 | 山东农业大学 | Fast preparation COF @ NH2-method of CNT composite |
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