A photoelectrochemical sensor for detecting chloramphenicol and its construction method and application

Abstract

The present invention relates to the field of electrochemical detection technology, and more particularly to a photoelectrochemical sensor for detecting chloramphenicol, wherein the photoelectrochemical sensor is based on molybdenum iron selenide cadmium telluride composite material, and the molybdenum iron selenide cadmium telluride composite material is modified with an ITO electrode to construct a photoelectrochemical sensor. In the photoelectrochemical sensor of the present invention, molybdenum iron selenide and cadmium telluride composite materials are used to modify the ITO electrode, and molybdenum iron selenide and cadmium telluride have a good synergistic effect, can accelerate the transfer rate of electrons, have a strong photoelectrochemical response to chloramphenicol, can be used for fast and easy detection of chloramphenicol, have a lower detection limit, high stability, good reproducibility and anti-interference, have good reliability, and can be used for the practical application of detecting chloramphenicol.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical detection, and particularly relates to a photoelectrochemical sensor for detecting chloramphenicol and a construction method and application thereof. Background Art

[0002] Chloramphenicol is an optically active amide antibiotic with strong antibacterial effects. It is mainly used as the drug of choice for typhoid and paratyphoid fever caused by sensitive strains. However, in recent years, improper use of chloramphenicol can cause some serious side effects and adverse reactions in humans, causing aplastic anemia, agranulocytosis, neurotoxin reactions, etc. Various studies have shown that animal-derived products may contain residual chloramphenicol, which may pose a threat to human health. The European Union, China, the United States and other countries have introduced policies prohibiting the use of chloramphenicol in livestock (including bees), and now strictly require that chloramphenicol must not be detected in animal-derived foods.

[0003] At present, there are many methods for detecting chloramphenicol, such as gas phase method, liquid phase method, thin layer chromatography, biosensor method and microbial method, but these methods have disadvantages such as time-consuming, labor-intensive and high cost. The photoelectrochemical detection method has the characteristics of low cost, high sensitivity and simple instrument operation, and has broad application prospects in important fields such as immunoassay and biotechnology. It is very necessary and important to develop an electrochemical sensor with high specificity, high sensitivity and low detection limit for rapid detection of chloramphenicol. Summary of the invention

[0004] The object of the present invention is to provide a photoelectrochemical sensor for detecting chloramphenicol and a construction method thereof, which is used for detecting chloramphenicol and has high specificity and sensitivity.

[0005] To achieve the above objectives, the present invention provides a photoelectrochemical sensor for detecting chloramphenicol. The photoelectrochemical sensor is based on a molybdenum iron selenide-cadmium telluride composite material, and the molybdenum iron selenide-cadmium telluride composite material is used to modify an ITO electrode to construct a photoelectrochemical sensor.

[0006] The present invention also provides a method for constructing a photoelectrochemical sensor, comprising the following steps:

[0007] (1) adding cadmium chloride into water to prepare a cadmium chloride solution, and dropping thioglycolic acid into the solution to adjust the pH value of the solution to 8.5-10;

[0008] (2) taking the solution obtained in step (1), diluting it with water, adding molybdenum iron selenide under a protective atmosphere and stirring evenly, then sequentially adding sodium borohydride and sodium tellurite under stirring, heating to 80-95° C. and reflux for 2-4 h, centrifuging, washing, and vacuum drying to obtain a molybdenum iron selenide-cadmium telluride composite material;

[0009] (3) dispersing the molybdenum iron selenide-cadmium telluride composite material in a solvent to obtain a dispersion, applying the dispersion droplets on an ITO electrode, and drying the dispersion to obtain a modified electrode;

[0010] (4) Using the modified electrode obtained in step (3) as a working electrode, a counter electrode, and a reference electrode to form a three-electrode system, and combining it with an electrochemical workstation to construct an electrochemical sensor.

[0011] Preferably, in the method for constructing the above-mentioned photoelectrochemical sensor, in the step (1), the mass percentage concentration of the cadmium chloride solution is 1-2%, and the ratio of cadmium chloride to thioglycolic acid is 1-2 g:1 mL.

[0012] Preferably, in the above-mentioned method for constructing a photoelectrochemical sensor, in the step (2), 2 to 3 times the volume of the solution is added for dilution with water, the ratio of the solution, molybdenum iron selenide and sodium tellurite is 80 to 120 mL: 0.3 to 0.4 g: 0.32 to 0.45 g, and the amount of sodium borohydride added is 4 to 5 times the mass of sodium tellurite.

[0013] Preferably, in the above-mentioned method for constructing a photoelectrochemical sensor, in the step (3), the solvent is N,N-dimethylformamide, and the concentration of the dispersion is 2.5-4 mg / mL.

[0014] Preferably, in the above-mentioned method for constructing a photoelectrochemical sensor, the molybdenum iron selenide is prepared by the following method: dissolving ferric chloride and sodium molybdate in water to obtain a mixed solution, mixing hydrazine hydrate and selenium powder, adding them dropwise to the mixed solution to mix, performing a hydrothermal reaction, and after the reaction is completed, centrifuging, washing, and drying to obtain molybdenum iron selenide.

[0015] Preferably, in the above-mentioned method for constructing the photoelectrochemical sensor, the temperature of the hydrothermal reaction is 150-200° C., and the reaction time is 8-15 h.

[0016] Application of the above-mentioned photoelectrochemical sensor in the detection of chloramphenicol.

[0017] Preferably, in the above application, the photoelectric chemical sensor is used to detect the photocurrent values ​​I of a series of chloramphenicol standard solutions with different concentrations and the photocurrent value I0 of a blank sample with a concentration of 0, and the difference I between the photocurrent value I and the photocurrent value I0 is used. p A linear correlation was performed with the corresponding chloramphenicol concentration to obtain a quantitative detection model.

[0018] Compared with the existing technology, the present invention has the following beneficial effects:

[0019] 1. In the photoelectrochemical sensor of the present invention, an ITO electrode is modified by a composite material of molybdenum iron selenide and cadmium telluride. Molybdenum iron selenide and cadmium telluride have a good synergistic effect, can accelerate the electron transfer rate, have a strong photoelectrochemical response to chloramphenicol, and can be used to quickly and easily detect chloramphenicol.

[0020] 2. The photoelectrochemical sensor of the present invention is used to detect chloramphenicol at 7.50×10 -14 ~2.00×10 -10 It shows a good linear relationship within the mol / L concentration range, has a low detection limit, high stability, good reproducibility and anti-interference, and its spiked recovery rate for sample detection is 99.00% to 104.42%. It has good reliability and can be used in the practical application of detecting chloramphenicol. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a scanning electron microscope image of molybdenum iron selenide prepared in Example 1 of the present invention.

[0022] Figure 2 1 is an X-ray photoelectron spectrum diagram of each material in the embodiments and comparative examples of the present invention.

[0023] FIG3 (a) is a comparison diagram of the response peak current values ​​of each modified electrode in the embodiment of the present invention and the comparative example without adding chloramphenicol solution; (b) is a comparison diagram of the response peak current values ​​after adding chloramphenicol solution.

[0024] Figure 4 The impedance spectra of each modified electrode in the embodiments of the present invention and the comparative examples are shown in FIG.

[0025] FIG. 5 (a) is a graph showing the relationship between the chloramphenicol concentration and the response peak current in Application Example 1 of the present invention; and (b) is a graph showing the linear relationship between the chloramphenicol concentration and the response peak current difference.

[0026] FIG6 (a) shows the relationship between the chloramphenicol response peak current and the pH of the buffer solution in Application Example 1 of the present invention; (b) shows the relationship between the chloramphenicol response peak current and the pH of the buffer solution without adding chloramphenicol.

[0027] Figure 7 The stability of chloramphenicol detection using the molybdenum iron selenide-cadmium telluride modified electrode in Application Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0029] Example 1

[0030] A photoelectrochemical sensor for detecting chloramphenicol is based on a molybdenum iron selenide-cadmium telluride composite material. An ITO electrode modified with the molybdenum iron selenide-cadmium telluride composite material is used as a working electrode to construct a photoelectrochemical sensor.

[0031] The method for constructing a photoelectrochemical sensor for detecting chloramphenicol comprises the following steps:

[0032] (1) Preparation of molybdenum iron selenide:

[0033] Weigh 0.2022g of ferric chloride hexahydrate and 0.2046g of sodium molybdate and dissolve them in 20mL of distilled water to obtain a mixed solution; weigh 0.1213g of selenium powder, slowly add 10mL of hydrazine hydrate and mix well, stir for 20min, then add it dropwise to the prepared mixed solution and mix well, transfer the solution to a reactor, and keep it at 180°C for 12h; naturally cool to room temperature, then centrifuge at 5500r / min for 5min, remove the supernatant after centrifugation to obtain a solid product, first wash it with anhydrous ethanol and wash it thoroughly, then centrifuge it at 3500r / min for 5min, wash it three times continuously, then wash the solid product three times with double distilled water, place it in a vacuum drying oven at 45°C for 12h to obtain a black solid powder, which is molybdenum iron selenide. The scanning electron microscope image of molybdenum iron selenide is shown in Figure 1 ;

[0034] (2) Preparation of molybdenum iron selenide-cadmium telluride composite materials:

[0035] Weigh 1.6959 g of cadmium chloride, add 120 mL of double distilled water, and gradually add 1 mL of thioglycolic acid (TGA) dropwise within 10 min while stirring. At this time, the solution becomes milky white, and then adjust the solution to pH = 9.0 with 0.20 mol / L NaOH solution;

[0036] Take 25mL of the above solution and add 60mL of double distilled water. Under the protection of nitrogen, add 0.0800g of molybdenum iron selenide powder, quickly add 0.4023g of sodium borohydride powder while stirring rapidly, slowly add 0.0888g of sodium tellurite powder, continue to protect with nitrogen, heat to 90°C in a reflux device and reflux for 3h, centrifuge at 5500r / min for 5min after cooling, absorb the solid product obtained after the supernatant, first wash it with anhydrous ethanol and wash it thoroughly, centrifuge it at 3500r / min for 5min after washing, wash it three times continuously, then wash the product three times continuously with double distilled water, place it in a vacuum drying oven, and dry it at 50°C for 12h to obtain a molybdenum iron selenide-cadmium telluride composite material;

[0037] (3) Preparation of modified electrodes:

[0038] Weigh 3 mg of molybdenum iron selenide-cadmium telluride composite material, add 1 mL of N,N-dimethylformamide (DMF), and ultrasonicate for 20 min to disperse it evenly to obtain a dispersion liquid. Then, measure 10 μL of the dispersion liquid and apply it on a clean ITO electrode, and spread it thinly and evenly without aggregation, and air-dry it naturally to obtain a molybdenum iron selenide-cadmium telluride composite modified electrode (FeMoSe2@CdTe).

[0039] (4) A three-electrode system consisting of the modified electrode as the working electrode, the Ag / AgCl electrode as the reference electrode, and the platinum wire as the counter electrode was used in conjunction with an electrochemical workstation to construct an electrochemical sensor.

[0040] Comparative Example 1

[0041] Weigh 3 mg of molybdenum iron selenide, which was prepared in the same manner as in Example 1, add 1 mL of N,N-dimethylformamide (DMF), and ultrasonicate for 20 min to evenly disperse it to obtain a dispersion. Then, measure 10 μL of the dispersion and drop it on a clean ITO electrode, spread it thinly and evenly without aggregation, and air-dry it naturally to obtain a molybdenum iron selenide modified electrode.

[0042] Comparative Example 2

[0043] Preparation of cadmium telluride:

[0044] Weigh 1.6959g of cadmium chloride, add 120mL of double distilled water, and gradually add 1mL of thioglycolic acid (TGA) dropwise within 10min while stirring. At this time, the solution appears milky white, and then the solution is adjusted to pH=9.0 with 0.20mol / L NaOH solution. Take 25mL of the above solution in a 150mL flask, add 60mL of double distilled water, and under nitrogen protection, quickly stir while quickly adding 0.4026g of sodium borohydride powder, and then slowly add 0.0888g of sodium tellurite powder, continue to use nitrogen protection, heat to 90℃ in a reflux device and reflux for 3h, stop heating, cool, and centrifuge to obtain a precipitate washed three times with anhydrous ethanol and distilled water respectively, and the obtained product is placed in a vacuum drying oven and dried at 60℃ for 10h to obtain cadmium telluride.

[0045] Weigh 3 mg of cadmium telluride, add 1 mL of N,N-dimethylformamide (DMF), and ultrasonicate for 20 min to evenly disperse it to obtain a dispersion. Then, measure 10 μL of the dispersion and drop it on a clean ITO electrode, and spread it thinly and evenly without aggregation. Let it dry naturally to obtain a cadmium telluride modified electrode.

[0046] XRD patterns of cadmium telluride, molybdenum iron selenide, and molybdenum iron selenide-cadmium telluride composites are shown in Figure 2. Figure 2As can be seen from the figure, CdTe has an obvious peak at 32°, FeMoSe2 has an obvious peak at 29°, and FeMoSe2@CdTe has a double peak between 29° and 32°, indicating that molybdenum iron selenide and cadmium telluride are successfully composited.

[0047] Characterization of different modified electrodes: The i-t method was used to detect the response peak current of cadmium telluride, molybdenum iron selenide, and molybdenum iron selenide-cadmium telluride composite modified electrodes without and with chloramphenicol added. The modified electrode was used as the working electrode, the Ag / AgCl electrode was used as the reference electrode, and the platinum wire was used as the counter electrode. A blue light with an intensity of 20 W was used as the excitation light source. 4 mL of 0.10 mol / L PBS buffer solution (pH = 6) was added to the electrolytic cell. A 2.5×10 -6 mol / L chloramphenicol standard solution was used for detection, and the results are shown in Figure 3. As shown in Figure 3, the response peak current change of FeMoSe2@CdTe composite material is much greater than that of CdTe and FeMoSe2, indicating that the photoelectrochemical sensor constructed based on FeMoSe2@CdTe composite material has a good photoelectrochemical response to chloramphenicol.

[0048] The impedance of the electrodes modified by each material was detected in the electrolyte of 0.5mmol / L[Fe(CN)6] 3- / 4- In the solution, the electrodes modified by each material were detected by the AC impedance method. The results are as follows Figure 4 As shown, the order of diameter size of each electrode can be obtained: molybdenum iron selenide > cadmium telluride > molybdenum iron selenide@cadmium telluride. The results show that the composite material of molybdenum iron selenide (FeMoSe2) and cadmium telluride (CdTe) has a good synergistic effect and can accelerate the transfer rate of electrons. The ITO electrode modified with molybdenum iron selenide-cadmium telluride (FeMoSe2@CdTe) composite material has the advantage of promoting electron transfer in electrochemical processes.

[0049] Application Example 1

[0050] The photoelectrochemical sensor of Example 1 was used to detect chloramphenicol. A three-electrode system was formed with a molybdenum iron selenide-cadmium telluride composite modified electrode as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum wire as the counter electrode. The peak currents of chloramphenicol at different concentrations were tested by the i-t method in a PBS buffer solution with a pH of 4.5 and a concentration of 0.10 mol / L. As shown in FIG5 , 7.50×10 -14 ~2.00×10 -10 mol / L concentration range, the peak current difference of the response is linearly related to the chloramphenicol concentration, I p (μA)=-8.00×10 -8 logC(mol / L)-1.00×10 -6 (R2 =0.9929). The corresponding peak current of the actual sample is detected, and the actual sample concentration is obtained according to the linear relationship.

[0051] (1) Optimal detection conditions:

[0052] Using the working electrode modified with FeMoSe2@CdTe composite material, the i-t method was used to detect the chloramphenicol standard solution (concentration of 9.10×10 -5 mol / L), the results are shown in Figure 6. The response peak current generated by detecting chloramphenicol in buffered saline solutions of various pH values ​​is compared with the response peak current detected when no chloramphenicol solution is added. In the pH=3-4.5 range, the response peak current when no chloramphenicol solution is added and the response peak current when chloramphenicol solution is added gradually increase until the response peak current reaches the maximum at pH=4.5, and the difference between the two is also increasing; in the pH=5-6 range, the response peak current when no chloramphenicol solution is added and the response peak current when chloramphenicol solution is added gradually decreases. It can be seen from the figure that the PBS buffer solution of pH=4.5 is the optimal detection condition.

[0053] (2) Anti-interference

[0054] Under the same experimental conditions, the effects of other substances on the photoelectrochemical behavior of the FeMoSe2@CdTe working electrode were investigated. First, chloramphenicol (concentration 5.00×10 -12 mol / L), and then add interfering substances with a concentration of 100 times the standard chloramphenicol, detect the peak current value, and calculate the relative error of the two peak current values. The results are shown in Table 1. It can be seen from the table that the relative error of the response peak current is within ±5%. The results show that the FeMoSe2@CdTe working electrode has good anti-interference ability for the detection of chloramphenicol.

[0055] Table 1 Effects of different interfering substances on the photoelectrochemical behavior of FeMoSe2@CdTe working electrode

[0056]

[0057]

[0058] (3) Stability and reproducibility

[0059] Under the optimal conditions, the i~t method was used to detect 5.00×10 -12 mol / L chloramphenicol standard solution, tested 20 times in a row. The test results are shown in Figure 7 , the relative standard deviation (RSD) was calculated to be 0.32%. The results showed that the current was relatively stable, indicating that the electrode had good stability in the short term. After the modified electrode was placed in a refrigerator for 7 days, it was used again to detect the same concentration of chloramphenicol under the same conditions and found that its response peak current did not change much, which can prove that the FeSeMo@CdTe composite material has better reproducibility in detecting chloramphenicol.

[0060] (4) Detection and recovery rate experiment of actual samples

[0061] Chloramphenicol eye drops (8 mg / 20 mL, Sichuan Mei Da Kang Hua Kang Pharmaceutical Co., Ltd.) were diluted with PBS solution of optimal pH to prepare sample solution, which was stored for later use. 10 chloramphenicol tablets (0.25 g / tablet, Chengdu Jinhua Pharmaceutical Co., Ltd.) were crushed into powder in a quartz mortar, and the mass of 1 tablet was weighed, dissolved with 30 mL of anhydrous ethanol, ultrasonically mixed, and then centrifuged at 5000 r / min to obtain the supernatant, which was then diluted to a sample solution of a certain concentration and stored for later use. 10 ml of blank urine sample was taken, 2 ml of acetonitrile solution (1:3) was added to precipitate the protein, ultrasonically mixed for 2 min, centrifuged at 4500 r / min for 10 min, filtered, and stored for later use.

[0062] Under the optimal detection conditions, the i~t method was used to detect the response peak current value of the FeMoSe2@CdTe working electrode to the treated chloramphenicol eye drops, chloramphenicol tablet solution and urine solution, and then the response peak current of the chloramphenicol standard solution was detected. The chloramphenicol content was calculated within the linear range of the experiment, and the spike recovery rate was calculated according to formula (1). In formula (1), C1 represents the actual concentration of the sample, C2 represents the actual concentration of the chloramphenicol solution, and C 标 The results are shown in Table 2.

[0063]

[0064] As shown in Table 2, the spiked recovery rate of chloramphenicol samples is between 99.00% and 104.42%, which does not exceed the reasonable range of 95.00% to 105.00%, indicating that the photoelectrochemical sensor constructed in Example 1 can be used for chloramphenicol detection in actual samples.

[0065] Table 3.2 Actual sample spike recovery rate analysis (N=5)

[0066]

[0067] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A method for constructing a photoelectrochemical sensor for detecting chloramphenicol, characterized in that: The photoelectrochemical sensor is based on a molybdenum iron selenide-cadmium telluride composite material, and the molybdenum iron selenide-cadmium telluride composite material is modified on an ITO electrode to construct a photoelectrochemical sensor; the construction method of the photoelectrochemical sensor comprises the following steps: (1) Add cadmium chloride to water to prepare a cadmium chloride solution, add thioglycolic acid dropwise to the solution, and adjust the pH value of the solution to 8.5-10; (2) taking the solution obtained in step (1), adding water to dilute it, adding molybdenum iron selenide under a protective atmosphere and stirring evenly, then adding sodium borohydride and sodium tellurite in sequence under stirring, heating to 80-95° C. and reflux for 2-4 hours, centrifuging, washing, and vacuum drying to obtain a molybdenum iron selenide-cadmium telluride composite material; (3) dispersing the molybdenum iron selenide-cadmium telluride composite material in a solvent to obtain a dispersion, applying the dispersion droplets on an ITO electrode, and drying the droplets to obtain a modified electrode; (4) Using the modified electrode obtained in step (3) as a working electrode, a counter electrode, and a reference electrode to form a three-electrode system, and combining it with an electrochemical workstation to construct an electrochemical sensor; The molybdenum iron selenide is prepared by the following method: dissolving ferric chloride and sodium molybdate in water to obtain a mixed solution, mixing hydrazine hydrate and selenium powder, adding the mixture to the mixed solution, performing a hydrothermal reaction, and after the reaction is completed, centrifuging, washing, and drying to obtain the molybdenum iron selenide.

2. The method for constructing a photoelectrochemical sensor according to claim 1, characterized in that: In the step (1), the mass percentage concentration of the cadmium chloride solution is 1-2%, and the ratio of cadmium chloride to thioglycolic acid is 1-2 g:1 mL.

3. The method for constructing a photoelectrochemical sensor according to claim 1, wherein in step (2), 2 to 3 times the volume of the solution is added for dilution, the ratio of solution, molybdenum iron selenide and sodium tellurite is 80 to 120 mL: 0.3 to 0.4 g: 0.32 to 0.45 g, and the amount of sodium borohydride added is 4 to 5 times the mass of sodium tellurite.

4. The method for constructing a photoelectrochemical sensor according to claim 1, characterized in that: In the step (3), the solvent is N,N-dimethylformamide, and the concentration of the dispersion is 2.5-4 mg / mL.

5. The method for constructing a photoelectrochemical sensor according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 150-200° C., and the reaction time is 8-15 hours.

6. A photoelectrochemical sensor for detecting chloramphenicol, characterized in that: The photoelectrochemical sensor is constructed by the construction method described in any one of claims 1 to 5.

7. Use of the photoelectrochemical sensor as claimed in claim 6 in detecting chloramphenicol.

8. The use according to claim 7, characterized in that: The photoelectric chemical sensor is used to detect the photocurrent values ​​I of a series of chloramphenicol standard solutions with different concentrations and the photocurrent value I0 of a blank sample with a concentration of 0, and the difference I between the photocurrent value I and the photocurrent value I0 is used to determine the photocurrent value I of the blank sample. p A linear correlation was performed with the corresponding chloramphenicol concentration to obtain a quantitative detection model.

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