CN116124848A - Preparation method and application of molecularly imprinted electrochemical sensor - Google Patents
Preparation method and application of molecularly imprinted electrochemical sensor Download PDFInfo
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- G01N27/3275—Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction
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- G01N27/3275—Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction
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Abstract
The invention discloses a preparation method and application of a molecular imprinting electrochemical sensor; (1) Dispersing boron nitride in a first solvent to obtain a dispersion liquid A; ultrasonic treatment is carried out on the dispersion liquid A, and the dispersion liquid A is centrifuged to obtain a precipitate A; (2) Centrifugally washing the precipitate A, and drying the precipitate to obtain 2D-hBN nano-sheets; (3) Dispersing the 2D-hBN nano-sheets in a second solvent and deoxidizing to obtain a dispersion liquid B; (4) Transferring the dispersion liquid B into a reactor for heating reaction, cooling after the reaction, centrifuging, and taking supernatant to obtain a boron nitride quantum dot material; (5) Mixing a boron nitride quantum dot material with a chitosan solution to obtain a mixed solution; (6) Coating the mixed liquid drop on the electrode, and drying to obtain a modified electrode; (7) Placing the modified electrode in a phosphate buffer solution containing o-phenylenediamine, beta-cyclodextrin and folic acid for electrochemical polymerization to form a film; (8) And (5) airing and eluting to obtain the molecular imprinting electrochemical sensor. Application: the prepared electrochemical sensor is used for folic acid detection.
Description
Technical Field
The invention relates to the technical field of electrochemical sensor preparation, in particular to a preparation method of a molecular imprinting electrochemical sensor and application of the molecular imprinting electrochemical sensor in folic acid content detection.
Background
Folic acid, also known as pteroylglutamic acid, is a water-soluble vitamin B, widely found in fruits, vegetables and animal livers. Folic acid is relatively stable in air and is easy to decompose in neutral and alkaline environments after being irradiated by ultraviolet light. Folic acid is not synthesized in humans and is only ingested via foods or dietary supplements, and therefore tends to cause folate deficiency. Folate deficiency can lead to physiological dysfunction and certain diseases such as neonatal nerve tube deformity, osteoporosis, and psychotic disorders, and so on, and intake and supplementation of folic acid is becoming a health problem of concern worldwide. With the continued depth of folic acid research, health problems arising from excessive intake of folic acid have increased, for example: zinc deficiency, nausea, anorexia, and other gastrointestinal syndromes. Therefore, reasonable intake of folic acid is particularly important, so that the folic acid content is rapidly and accurately detected, the folic acid is an important technical means for guiding folic acid intake and ensuring the safety and effectiveness of folic acid, and is an effective index for diagnosing various diseases and has important significance for clinical diagnosis.
Currently, many folic acid detection methods have been developed and are becoming more sophisticated, and among the reported detection methods, the microbiological method is generally recognized as a preferred scheme because of its wide measurement range and low cost, but it requires a longer detection period. High performance liquid chromatography and liquid chromatography tandem mass spectrometry have good selectivity, but the problems of high equipment cost, long time consumption and the like still exist in the analysis process. The capillary electrophoresis method has the advantages of small sample amount and high separation efficiency, but has the problems of poor reproducibility, toxic organic matters and the like. Colorimetric and ELISA methods are faster in detection but have low sensitivity and require pretreatment to remove interference from the matrix. There are reports in the literature that folic acid can be detected electrochemically, but there are also problems of poor sensitivity and selectivity. The molecular imprinting technology and the electrochemical technology are combined, so that high-selectivity detection of a target object can be realized, but in the conventional molecular imprinting technology, a single template molecule and a single functional monomer are used, and the detection sensitivity of the single functional monomer to folic acid still has a progress space.
Disclosure of Invention
The invention aims to overcome the defects in the existing folic acid detection method, and provides a preparation method of a molecular imprinting electrochemical sensor, and the prepared molecular imprinting electrochemical sensor is used for detecting the content of folic acid, so that the high-sensitivity and high-selectivity detection of folic acid is realized.
The invention is realized by the following technical scheme:
the preparation method of the molecular imprinting electrochemical sensor is characterized by comprising the following steps of:
1. preparing a boron nitride quantum dot material:
(1) Dispersing boron nitride in a first solvent to obtain a dispersion liquid A; then carrying out ultrasonic treatment and centrifugation on the dispersion liquid A to obtain a precipitate A;
(2) Centrifuging and washing the precipitate A, and drying the precipitate after centrifuging to obtain 2D-hBN nano-sheets;
(3) Dispersing the 2D-hBN nano-sheets in a second solvent and deoxidizing to obtain a dispersion liquid B;
(4) Transferring the dispersion liquid B into a reactor for heating reaction, cooling after the reaction, centrifuging, and taking supernatant to obtain a boron nitride quantum dot material;
2. preparation of modified electrode:
(1) Mixing the boron nitride quantum dot material with a chitosan solution to obtain a mixed solution;
(2) The mixed liquid is dripped on an electrode, and the electrode is dried to obtain a modified electrode;
3. preparation of a molecularly imprinted electrochemical sensor:
(1) Placing the modified electrode in a phosphate buffer solution containing o-phenylenediamine, beta-cyclodextrin and folic acid for electrochemical polymerization to form a film;
(2) And then airing and eluting to obtain the molecular imprinting electrochemical sensor.
Specifically, the preparation method of the molecular imprinting electrochemical sensor provided by the invention tries to use the difunctional monomer, so that the folic acid molecular imprinting electrochemical sensor based on the identification of the difunctional monomer is prepared, and the high-sensitivity and high-selectivity detection of folic acid is realized.
Further, a preparation method of the molecular imprinting electrochemical sensor comprises the following steps: 1. preparing a boron nitride quantum dot material: the mass-to-volume ratio of the boron nitride to the first solvent in the step (1) is 1.0-3.0mg/mL; the first solvent is isopropanol; the time of the ultrasonic treatment is 8-12 hours. Wherein: the boron nitride used in the present invention is a commercially available boron nitride material.
Further, a preparation method of the molecular imprinting electrochemical sensor comprises the following steps: 1. preparing a boron nitride quantum dot material: and (2) adding acetone into the precipitate A for centrifugal washing, and carrying out vacuum drying on the precipitate at 50-70 ℃ for 12-24 hours after centrifugation to obtain the 2D-hBN nano-sheet.
Further, a preparation method of the molecular imprinting electrochemical sensor comprises the following steps: 1. preparing a boron nitride quantum dot material: step (3), dispersing the 2D-hBN nano-sheets in a second solvent, and introducing nitrogen to remove oxygen to obtain a dispersion liquid B; wherein: the second solvent is ethanol; the mass volume ratio of the 2D-hBN nano-sheet to the second solvent is 1.0-4.0mg/mL.
Further, a preparation method of the molecular imprinting electrochemical sensor comprises the following steps: 1. preparing a boron nitride quantum dot material: the reaction temperature in the step (4) is 150-200 ℃ and the reaction time is 8-12 hours.
Further, a preparation method of the molecular imprinting electrochemical sensor comprises the following steps: 2. preparation of modified electrode: step (1) mixing the boron nitride quantum dot material with chitosan solution with the concentration of 0.01-2.0wt% according to the volume ratio of (2-5): 1, uniformly mixing to obtain a mixed solution; wherein: the chitosan solution is as follows: and dissolving chitosan in acetic acid solution.
Further, a preparation method of the molecular imprinting electrochemical sensor comprises the following steps: 2. preparation of modified electrode: the electrode in the step (2) is a glassy carbon electrode; the drying temperature is 40-70 ℃ and the drying time is 10-30 minutes.
Further, a preparation method of the molecular imprinting electrochemical sensor comprises the following steps: 3. preparation of a molecularly imprinted electrochemical sensor: the molar ratio between the o-phenylenediamine, the beta-cyclodextrin and the folic acid in step (1) is (0.1-2): (0.1-4): (0.5-2); the pH of the buffer solution is 4.5-8.5; the potential of the electrochemical polymerization film is-0.2-1.2V, the scanning circle number is 10, and the scanning speed is 0.05V/s.
Preferably, the molar ratio between o-phenylenediamine, beta-cyclodextrin and folic acid is 2:2:1. the pH of the preferred buffer is 6.5.
Further, a preparation method of the molecular imprinting electrochemical sensor comprises the following steps: 3. preparation of a molecularly imprinted electrochemical sensor: and (3) performing electrochemical polymerization to form a film, then performing natural air drying, and then placing the film in a 0.25mol/L NaOH solution for electrochemical elution, wherein the potential range during elution is 0-1.2V, the scanning circle number is 8, and the scanning speed is 0.05V/s, so as to obtain the molecularly imprinted electrochemical sensor.
The application of the molecular imprinting electrochemical sensor is characterized in that the molecular imprinting electrochemical sensor prepared by the method is applied to folic acid content detection.
The invention has the beneficial effects that:
(1) The preparation method of the molecular imprinting electrochemical sensor provided by the invention is simple, and the prepared folic acid molecular imprinting electrochemical sensor based on double-monomer recognition can realize high-sensitivity and high-selectivity detection of folic acid.
(2) According to the invention, the boron nitride quantum dot material is used for modifying the electrode, the current of the modified electrode is about twice that of the bare electrode, and the electrochemical performance of the modified electrode is obviously improved. The folic acid molecular imprinting electrochemical sensor prepared by utilizing the boron nitride quantum dot material modified electrode provided by the invention has the advantages that the logarithmic value (LogC) of folic acid concentration and the current difference DeltaI are in a linear relation within the concentration range of 0.005 nM-0.4 mu M, the detection limit is 0.0029nM, and the high-sensitivity detection is embodied.
(3) The molecular imprinting electrochemical sensor prepared by the invention is based on a boron nitride quantum dot material, is used for high-sensitivity identification of folic acid, and has higher sensitivity and stronger anti-interference performance.
(4) The folic acid molecular imprinting electrochemical sensor prepared by the method is used for specificity identification detection analysis of folic acid, and the detection method is simple and quick to operate and low in detection cost. The material for modifying the electrode by the method has simple preparation and low price, and solves the technical problems of complicated detection process, expensive detection equipment, high operation requirement on detection personnel, complex sample pretreatment preparation process and the like in the traditional folic acid detection process.
(5) In the method, the combination of the o-phenylenediamine and the beta-cyclodextrin is selected as a difunctional monomer, and compared with the traditional monofunctional monomer, the method has higher sensitivity and stronger anti-interference performance. The folic acid molecular imprinting electrochemical sensor prepared by the invention can realize high-sensitivity recognition and specific response to folic acid in a neutral environment.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a linear graph of response of the molecularly imprinted electrochemical sensor prepared in example 1 to folic acid at different concentrations;
FIG. 2 is the results of an anti-interference test for detecting folic acid by the molecular imprinting electrochemical sensor prepared in example 1;
FIG. 3 is a cyclic voltammogram of the materials prepared in example 1 and comparative examples 1-3 in potassium ferricyanide solution.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
A preparation method of a molecular imprinting electrochemical sensor comprises the following steps:
1. preparing a boron nitride quantum dot material:
(1) 100.0mg of boron nitride was dispersed in 50mL of isopropanol and stirred at 50℃for 24 hours to obtain a dispersion A; then carrying out ultrasonic treatment on the dispersion liquid A for 10 hours, and centrifuging to obtain white powdery precipitate A;
(2) Adding acetone into the obtained precipitate A for centrifugal washing, and after centrifugation, putting the precipitate into a vacuum drying oven for drying at 60 ℃ for 24 hours to obtain 2D-hBN nano-sheets;
(3) Dispersing the obtained 2D-hBN nano-sheets in ethanol, and introducing nitrogen for 30 minutes to remove oxygen to obtain a dispersion liquid B; and in the step, the mass volume ratio of the 2D-hBN nano-sheet to the ethanol is 1.0mg/mL;
(4) Transferring the obtained dispersion liquid B into a reactor, heating to 180 ℃ for reaction for 8 hours, cooling after the reaction, centrifuging, and taking supernatant to obtain a boron nitride quantum dot material;
2. preparation of modified electrode:
(1) Mixing the obtained boron nitride quantum dot material with a chitosan solution with the concentration of 1.0 weight percent to obtain a mixture with the concentration of 3:1, uniformly mixing the mixture in a volume ratio to obtain a mixed solution;
(2) The obtained mixed liquid is dripped on a glassy carbon electrode, and then the glassy carbon electrode is placed in a baking oven at 60 ℃ for drying for 15 minutes, so as to obtain a modified electrode;
3. preparation of a molecularly imprinted electrochemical sensor:
(1) Placing the obtained modified electrode in a phosphate buffer solution with the pH value of 6.5 for electrochemical polymerization to form a film; wherein: the buffer solution contains 2.0mmol of o-phenylenediamine, 2.0mmol of beta-cyclodextrin and 1.0mmol of folic acid;
(2) And (3) naturally airing after polymerization film forming, then placing into a 0.25mol/L NaOH solution for eluting, wherein the potential range during eluting is 0-1.2V, the scanning circle number is 8, and the scanning speed is 0.05V/s, so that the molecular imprinting electrochemical sensor can be obtained.
(1) Detection performance test of folic acid: at 5mM K 3 [Fe(CN) 6 ]And 0.1M KCl mixed solution, the molecularly imprinted electrochemical sensor prepared in the embodiment 1 is used as a working electrode, an Ag/AgCl electrode is used as a reference electrode, and a platinum wire electrode is used as an auxiliary electrode; the result of the test by using the differential pulse voltammetry to detect the electrochemical signal is shown in fig. 1, and as can be seen from fig. 1, when the molecular imprinting electrochemical sensor based on the boron nitride quantum dot material modified glassy carbon electrode prepared in the embodiment 1 is used for detecting folic acid, the logarithmic value (LogC) of folic acid concentration and the current difference delta I form a linear relationship within the concentration range of 0.005 nM-0.4 mu M, and as the folic acid concentration increases, the current difference increases, and the detection limit is 0.0029nM, thus the molecular imprinting sensor prepared by the invention can accurately detect folic acid.
(2) Anti-interference performance test: at 5mM K 3 [Fe(CN) 6 ]And 0.1M KCl mixed solution, the molecularly imprinted electrochemical sensor prepared in the embodiment 1 is used as a working electrode, an Ag/AgCl electrode is used as a reference electrode, and a platinum wire electrode is used as an auxiliary electrode; detecting electrochemical signals by using a differential pulse voltammetry, detecting electrochemical response signals of ascorbic acid, glucose, L-cysteine, vitamin B6, L-arginine and riboflavin, and evaluating anti-interference performance by using current variation; the anti-interference performance test result of the molecular imprinting electrochemical sensor prepared in the embodiment 1 of the invention is shown in a figure 2, and the result shows that the current difference of ascorbic acid, glucose, L-cysteine, vitamin B6 and riboflavin is one fourth of the current difference of folic acid, and the current difference of L-arginine is one third of the current difference of folic acid, so that the molecular imprinting electrochemical sensor prepared in the invention has specific identification on folic acid.
Comparative example 1
Comparative example 1 differs from example 1 in that: the glassy carbon electrode is directly modified by the boron nitride quantum dot material in comparative example 1, so that a modified electrode is obtained, namely the electrochemical polymerization film forming step is not carried out in comparative example 1.
Comparative example 2
Comparative example 2 differs from example 1 in that: comparative example 2 directly uses a glassy carbon electrode as a comparison, namely, the glassy carbon electrode is not subjected to a boron nitride quantum dot material modification step and an electrochemical polymerization film forming step in comparative example 2.
Comparative example 3
Comparative example 3 differs from example 1 in that: comparative example 3 the glassy carbon electrode was modified directly with the prepared 2D-hBN nanoplatelets, i.e. comparative example 3 did not make the 2D-hBN nanoplatelets into boron nitride quantum dot material, nor did it undergo the electrochemical polymerization film formation step.
And (3) testing: the electrodes prepared in example 1 and comparative examples 1 to 3 above were tested for cyclic voltammograms in potassium ferricyanide solution and the results are shown in fig. 3. The current value of the boron nitride quantum dot material modified electrode (comparative example 1) is obviously higher than that of the glassy carbon bare electrode (comparative example 2), which shows that the boron nitride quantum dot material is loaded on the glassy carbon bare electrode, the current value is increased, and the electrochemical performance is improved; and the current value of the boron nitride quantum dot material modified electrode (comparative example 1) is higher than that of the 2D-hBN nano-sheet modified electrode (comparative example 3), and further shows that the prepared boron nitride quantum dot material modified electrode has better performance. Comparing the cyclic voltammetry performance of the above electrodes in potassium ferricyanide solution, it can be seen that the current value of the molecular imprinting electrochemical sensor based on boron nitride quantum dots (example 1) is smaller than that of the boron nitride quantum dot material modified electrode (comparative example 1), the glassy carbon bare electrode (comparative example 2) and the 2D-hBN nano-sheet modified electrode (comparative example 3) due to the modification of the boron nitride quantum dot material and the electropolymerized molecular imprinting film on the surface of the glassy carbon bare electrode. Due to the modification of the boron nitride quantum material to the electrode substrate, the sensitivity of the sensor is effectively improved, and the molecular imprinting electrochemical sensor based on the boron nitride quantum dot material provided by the invention has the advantages of wider linear range of detection of the target folic acid, lower detection limit (figure 1) and better anti-interference performance (figure 2) in combination with the specific recognition of molecular imprinting.
Example 2
Example 2 differs from example 1 in that: the buffer of example 2 contained 1.0mmol of o-phenylenediamine, 1.0mmol of beta-cyclodextrin and 1.0mmol of folic acid; the remaining conditions of example 2 were the same as those of example 1.
Example 3
Example 3 differs from example 1 in that: the buffer of example 3 contained 4.0mmol of o-phenylenediamine, 4.0mmol of beta-cyclodextrin and 1.0mmol of folic acid; the remaining conditions of example 3 were the same as those of example 1.
Example 4
Example 4 differs from example 1 in that: the buffer of example 4 contained 2.0mmol of o-phenylenediamine, 1.0mmol of beta-cyclodextrin and 1.0mmol of folic acid; the remaining conditions of example 4 were the same as those of example 1.
Example 5
Example 5 differs from example 1 in that: the buffer of example 5 contained 2.0mmol of o-phenylenediamine, 4.0mmol of beta-cyclodextrin and 1.0mmol of folic acid; the remaining conditions of example 5 were the same as those of example 1.
Example 6
Example 6 differs from example 1 in that: the buffer of example 6 contained 2.0mmol of o-phenylenediamine, 0.0mmol of beta-cyclodextrin and 1.0mmol of folic acid; the remaining conditions of example 6 were the same as those of example 1.
Example 7
Example 7 differs from example 1 in that: the buffer of example 7 contained 0.0mmol of o-phenylenediamine, 2.0mmol of beta-cyclodextrin and 1.0mmol of folic acid; the remaining conditions of example 7 were the same as those of example 1.
The electrode materials prepared in examples 1 to 7 above were subjected to electrochemical tests, the results of which are shown in table 1 below:
table 1 shows the results of examples 1-7 after adjusting the molar proportions of o-phenylenediamine, beta-cyclodextrin and folic acid
The invention discovers that the proportion of template molecules and bifunctional monomers is one of the main factors influencing the electrochemical performance in the folic acid detection test based on the electrochemical method of the boron nitride carbon quantum dot molecular imprinting electrochemical sensor. By optimizing indexes such as sensitivity, selective response and the like of the electrochemical sensor, the electrochemical sensor with specific response to folic acid is constructed.
When a single functional monomer o-phenylenediamine (example 6) was used in combination with the data analysis of Table 1 above, the current difference was lower than for the difunctional monomer; when the single functional monomer beta-cyclodextrin is adopted (example 7), the electrochemical polymerization does not form a film, and the effect is not achieved; in example 1 of the present invention, in contrast to the multiple ratios, it was found that the electrochemical polymerization of a single functional monomer was ineffective, or the current difference was less than that of the difunctional monomer at the optimum ratio. The result shows that the invention adopts the difunctional monomer, thereby improving the sensitivity of the molecular imprinting electrochemical sensor.
The proportion condition of the template and the functional monomer is examined, and the experimental result shows that the molar proportion of the o-phenylenediamine, the beta-cyclodextrin and the folic acid has larger influence on the folic acid detection performance; when o-phenylenediamine: beta-cyclodextrin: the molar ratio of folic acid is 2:2: and 1, the prepared molecularly imprinted electrochemical sensor has better performance and the largest current difference value.
Example 8
Example 8 differs from example 1 in that: the pH of the buffer in example 8 was 4.5, the rest of the conditions being the same as in example 1.
Example 9
Example 9 differs from example 1 in that: the pH of the buffer in example 9 was 5.5, the rest of the conditions being the same as in example 1.
Example 10
Example 10 differs from example 1 in that: the pH of the buffer in example 10 was 7.5, the rest of the conditions being the same as in example 1.
Example 11
Example 11 differs from example 1 in that: the pH of the buffer in example 11 was 8.5, the rest of the conditions being the same as in example 1.
The electrode materials prepared in example 1 and examples 8 to 11 above were subjected to electrochemical tests, the results of which are shown in table 2 below:
table 2 shows the results of the tests on the materials obtained after pH adjustment of the buffers in example 1 and examples 8-11
| pH value of | Cyclic voltammetric current difference ΔI/percentage | |
| Example 1 | 6.5 | Maximum current difference |
| Example 8 | 4.5 | Elution damage to molecularly imprinted membranes |
| Example 9 | 5.5 | Elution damage to molecularly imprinted membranes |
| Example 10 | 7.5 | 38% of the maximum current difference |
| Example 11 | 8.5 | 17% of maximum current difference |
The invention discovers that the pH of the phosphate buffer in the preparation of the molecular imprinting electrochemical sensor is one of factors influencing folic acid detection performance in an electrochemical method detection folic acid test based on the boron nitride quantum dot molecular imprinting electrochemical sensor. By optimizing the sensitivity of the electrochemical sensor, an electrochemical sensor with a specific response to folic acid is constructed.
As can be seen from the test results in Table 2, the molecularly imprinted membrane is easily damaged when the electrochemical polymerization medium is in an acidic condition, the current difference is relatively small when the electrochemical polymerization medium is in an alkaline condition, the current difference is obviously increased when the electrochemical polymerization medium is in a neutral condition, and the current difference is maximum and the electrochemical performance is better when the electrochemical polymerization medium is in a pH 6.5 condition, so that the influence of the medium in the preparation process of the molecularly imprinted electrochemical sensor is larger. Experimental results prove that the pH of the preparation condition of the molecular imprinting electrochemical sensor has a great influence on the electrochemical performance of the molecular imprinting electrochemical sensor for detecting folic acid. When the detected medium condition is a neutral environment, the prepared molecularly imprinted electrochemical sensor has better detection performance on folic acid.
Example 12
Example 12 differs from example 1 in that: the temperature for preparing the boron nitride quantum dot material in example 12 was 150 ℃; the remaining conditions of example 12 were the same as those of example 1.
Example 13
Example 13 differs from example 1 in that: the temperature for preparing the boron nitride quantum dot material in example 13 is 200 ℃; the remaining conditions of example 13 were the same as those of example 1.
The electrode materials prepared in examples 1, 12 and 13 above were subjected to electrochemical tests, the results of which are shown in table 3 below:
table 3 shows the results of the temperature optimization test of the boron nitride quantum dot material
As can be seen from the results in Table 3, the temperature is one of the influencing factors in the preparation of the boron nitride carbon quantum dot material, and when the reaction temperature is 180 ℃, the current value is large, and when the reaction temperature is 150 ℃ or 200 ℃, the current value is reduced to some extent, which indicates that the electrochemical performance of the material prepared at 180 ℃ is good.
Example 14
Example 14 differs from example 1 in that: the mass to volume ratio of the 2D-hBN nanosheets to ethanol in example 14 was 2.0mg/mL; the remaining conditions of example 14 were the same as those of example 1.
Example 15
Example 15 differs from example 1 in that: the mass to volume ratio of the 2D-hBN nanosheets to ethanol in example 15 was 4.0mg/mL; the remaining conditions of example 15 were the same as those of example 1.
The electrode materials prepared in examples 1, 14 and 15 above were subjected to electrochemical tests, the results of which are shown in table 4 below:
table 4 shows the results of the optimized 2D-hBN nanosheet solution concentration test
| Material numbering | Concentration (mg/mL) | Cyclic voltammetry current value I/μa |
| Example 1 | 1 | Maximum peak current |
| Example 14 | 2 | Reduced by 25% from the maximum peak current |
| Example 15 | 4 | Reduced by 13% from the maximum peak current |
As can be seen from the results of Table 4, the current values of the 2D-hBN nanosheet solutions at different concentrations were less than 1.0mg/mL at the concentrations of 2.0mg/mL and 4.0mg/mL, indicating an improvement in the current values at the appropriate concentration ranges.
The above-described preferred embodiments of the present invention are only for illustrating the present invention, and are not to be construed as limiting the present invention. Obvious changes and modifications of the invention, which are introduced by the technical solution of the present invention, are still within the scope of the present invention.
Claims (10)
1. The preparation method of the molecular imprinting electrochemical sensor is characterized by comprising the following steps of:
1. preparing a boron nitride quantum dot material:
(1) Dispersing boron nitride in a first solvent to obtain a dispersion liquid A; then carrying out ultrasonic treatment and centrifugation on the dispersion liquid A to obtain a precipitate A;
(2) Centrifuging and washing the precipitate A, and drying the precipitate after centrifuging to obtain 2D-hBN nano-sheets;
(3) Dispersing the 2D-hBN nano-sheets in a second solvent and deoxidizing to obtain a dispersion liquid B;
(4) Transferring the dispersion liquid B into a reactor for heating reaction, cooling after the reaction, centrifuging, and taking supernatant to obtain a boron nitride quantum dot material;
2. preparation of modified electrode:
(1) Mixing the boron nitride quantum dot material with a chitosan solution to obtain a mixed solution;
(2) The mixed liquid is dripped on an electrode, and the electrode is dried to obtain a modified electrode;
3. preparation of a molecularly imprinted electrochemical sensor:
(1) Placing the modified electrode in a phosphate buffer solution containing o-phenylenediamine, beta-cyclodextrin and folic acid for electrochemical polymerization to form a film;
(2) And then airing and eluting to obtain the molecular imprinting electrochemical sensor.
2. The method for preparing the molecularly imprinted electrochemical sensor according to claim 1, wherein the preparation of the boron nitride quantum dot material is as follows: the mass-to-volume ratio of the boron nitride to the first solvent in the step (1) is 1.0-3.0mg/mL; the first solvent is isopropanol; the time of the ultrasonic treatment is 8-12 hours.
3. The method for preparing the molecularly imprinted electrochemical sensor according to claim 1, wherein the preparation of the boron nitride quantum dot material is as follows: and (2) adding acetone into the precipitate A for centrifugal washing, and carrying out vacuum drying on the precipitate at 50-70 ℃ for 12-24 hours after centrifugation to obtain the 2D-hBN nano-sheet.
4. The method for preparing the molecularly imprinted electrochemical sensor according to claim 1, wherein the preparation of the boron nitride quantum dot material is as follows: step (3), dispersing the 2D-hBN nano-sheets in a second solvent, and introducing nitrogen to remove oxygen to obtain a dispersion liquid B; wherein: the second solvent is ethanol; the mass volume ratio of the 2D-hBN nano-sheet to the second solvent is 1.0-4.0mg/mL.
5. The method for preparing the molecularly imprinted electrochemical sensor according to claim 1, wherein the preparation of the boron nitride quantum dot material is as follows: the reaction temperature in the step (4) is 150-200 ℃ and the reaction time is 8-12 hours.
6. The method for preparing a molecularly imprinted electrochemical sensor according to claim 1, wherein the preparation of the second modified electrode: step (1) mixing the boron nitride quantum dot material with chitosan solution with the concentration of 0.01-2.0wt% according to the volume ratio of (2-5): 1, uniformly mixing to obtain a mixed solution; wherein: the chitosan solution is as follows: and dissolving chitosan in acetic acid solution.
7. The method for preparing a molecularly imprinted electrochemical sensor according to claim 1, wherein the preparation of the second modified electrode: the electrode in the step (2) is a glassy carbon electrode; the drying temperature is 40-70 ℃ and the drying time is 10-30 minutes.
8. The method for preparing a molecular imprinting electrochemical sensor according to claim 1, wherein the preparation of the molecular imprinting electrochemical sensor comprises the following steps: the molar ratio between the o-phenylenediamine, the beta-cyclodextrin and the folic acid in step (1) is (0.1-2): (0.1-4): (0.5-2); the pH of the buffer solution is 4.5-8.5; the potential of the electrochemical polymerization film is-0.2-1.2V, the scanning circle number is 10, and the scanning speed is 0.05V/s.
9. The method for preparing a molecular imprinting electrochemical sensor according to claim 1, wherein the preparation of the molecular imprinting electrochemical sensor comprises the following steps: and (3) performing electrochemical polymerization to form a film, then performing natural air drying, and then placing the film in a 0.25mol/L NaOH solution for electrochemical elution, wherein the potential range during elution is 0-1.2V, the scanning circle number is 8, and the scanning speed is 0.05V/s, so as to obtain the molecularly imprinted electrochemical sensor.
10. The application of the molecular imprinting electrochemical sensor is characterized in that the molecular imprinting electrochemical sensor prepared by the preparation method of any one of claims 1-9 is applied to folic acid content detection.
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