A photoelectric probe for detecting phenylthiol, a photoelectrochemical sensor, a preparation method and applications thereof

Abstract

The application discloses a kind of detection benzene sulfhydryl photoelectric probe, photoelectrochemical sensor and preparation method and application, belong to chemical analysis detection technical field.The structure formula of detection benzene sulfhydryl photoelectric probe is:;6-hydroxy-2-naphthaldehyde, 2,4-dinitrofluorobenzene is dissolved in organic solvent, add alkali, and intermediate product A is obtained by heating reaction, intermediate product A, 4-pyridine acetonitrile and coupling catalyst are added to organic solvent, and the photoelectric probe for detecting benzene sulfhydryl is obtained by heating reaction.The application is based on the design and synthesis of detection benzene sulfhydryl photoelectric molecule, and constructs the photoelectrochemical sensor for detecting benzene sulfhydryl with superior performance, in the presence of benzene sulfhydryl, benzene sulfhydryl can specifically react with photoelectric probe molecule, change the structure and performance of photoelectric probe molecule, so that the response of photocurrent is significantly increased, and has good specific recognition effect to benzene sulfhydryl.

Description

Technical Field

[0001] This invention belongs to the field of chemical analysis and detection technology, specifically relating to a photoelectric probe, photoelectrochemical sensor, preparation method, and application for detecting thiophenol. Background Technology

[0002] Thiophenol (TP) is an important raw material in organic synthesis and has been widely used in the preparation of pesticides and pharmaceuticals. However, TP is also a highly toxic substance; excessive intake can cause various symptoms such as nausea, vomiting, nerve damage, and even death. Therefore, effective and accurate detection of thiophenol is crucial. To date, various analytical techniques have been applied to the determination of thiophenol, including ultraviolet-visible absorption spectrophotometry (Dyes Pigments 2017, 136, 354), fluorescence spectroscopy (Anal. Chem. 2022, 94, 5946.), high-performance liquid chromatography (J. Sep. Sci. 2017, 40, 2528.), Raman spectroscopy (J. Phys. Chem. C 2017, 121, 18254.), and electrochemiluminescence immunoassay (Anal. Chem. 2019, 91, 1353.).

[0003] Photoelectrochemical analysis methods are a class of electroanalytical chemical methods based on the photoelectric conversion effect. In photoelectrochemical detection, the excitation signal is light radiation, which is then converted into an electrical signal by a photosensitive material. This achieves complete separation of the excitation and detection signals, significantly reducing background noise and improving detection sensitivity. Currently, photoelectrochemical methods are widely used for the detection of biomolecules and metal ions. However, most of these methods use inorganic nanomaterials as photosensitizers and rely on biomolecules (such as antibodies and nucleic acids) to recognize the target analyte. This makes it difficult to achieve precise control of the photosensitizer and maintain the long-term stability of the sensor. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a photoelectric probe, photoelectric chemical sensor, preparation method, and application for detecting thiophene. Based on the designed and synthesized photoelectric probe molecule, a high-performance photoelectric chemical sensor for detecting thiophene is constructed, which has a good specific recognition effect on thiophene, a fast response speed, and a low detection limit.

[0005] This invention is achieved through the following technical solution: A photoelectric probe for detecting thiophene, wherein the photoelectric probe for detecting thiophene has the following structural formula: .

[0006] The present invention also discloses a photoelectrochemical sensor for detecting thiophenol, comprising the photoelectric probe for detecting thiophenol described above.

[0007] In this invention, the preparation method of the photoelectric probe for detecting thiophenol described above includes the following steps: (1) Dissolve 6-hydroxy-2-naphthaldehyde and 2,4-dinitrofluorobenzene in an organic solvent, add alkali, and heat to react to obtain intermediate product A; (2) Add intermediate product A, 4-pyridine acetonitrile and coupling catalyst to an organic solvent and heat to react to obtain a photoelectric probe for detecting thiophenol.

[0008] Further, the organic solvent mentioned in step (1) is one of dichloromethane, acetonitrile, N,N-dimethylformamide, and tetrahydrofuran, the base is one of sodium carbonate, potassium carbonate, and cesium carbonate, the reaction temperature for heating the reaction is 40~120℃, and the reaction time is 1~24h; the organic solvent mentioned in step (2) is one of methanol, ethanol, acetonitrile, and tetrahydrofuran, the coupling catalyst is one or more of piperidine, acetic acid, and sodium acetate, the reaction temperature for heating the reaction is 60~100℃, and the reaction time is 1~24h.

[0009] Further, in step (1), the molar ratio of 6-hydroxy-2-naphthaldehyde, 2,4-dinitrofluorobenzene, and base is 2:2:2.5; in step (2), the molar ratio of intermediate product A and 4-pyridineacetonitrile is 1:1.

[0010] This invention also discloses a method for preparing a photoelectrochemical sensor for detecting thiophenol. Titanium dioxide is synthesized hydrothermally on FTO conductive glass to obtain FTO / TiO2. The FTO / TiO2 is placed in a solution containing a silane coupling reagent and a photoelectric probe for detecting thiophenol and heated under reflux to obtain the photoelectrochemical sensor for detecting thiophenol.

[0011] Furthermore, the hydrothermal synthesis method of FTO / TiO2 is as follows: FTO conductive glass is placed in a reaction solution composed of water, concentrated hydrochloric acid, sodium chloride and tetrabutyl titanate, and the reaction temperature is controlled at 150~200℃ and the reaction time is 4~20h to carry out the hydrothermal reaction. After the reaction is completed, it is dried and calcined at high temperature to obtain FTO / TiO2. The ratio of sodium chloride, tetrabutyl titanate, concentrated hydrochloric acid, and deionized water is 0.8~1.2 g: 0.2-1.0 mL: 25~35 mL: 25~35 mL; the concentration of the concentrated hydrochloric acid is 36%~38%; the high-temperature calcination conditions are: heating to 450℃ at a rate of 2℃ / min and holding for 30 min.

[0012] Furthermore, the silane coupling reagent is: Wherein: R is selected from any alkyl chain with 1 to 18 carbon atoms, n is an integer from 0 to 18, and X is F, Cl, Br or I; the molar ratio of the silane coupling reagent and the photoelectric probe for detecting thiophenol is 2:1, and the heating reflux reaction time is 5h.

[0013] In this invention, the photoelectrochemical sensor for detecting thiophenol is described in its application in the detection of thiophenol.

[0014] Furthermore, an electrochemical workstation was used to conduct the tests with a three-electrode system. The photoelectrochemical sensor for detecting thiophenol was used as the working electrode, the saturated calomel electrode as the reference electrode, and the platinum wire electrode as the counter electrode. The test solution system contained 0.01–1 mol·L⁻¹ of... -1 Ascorbic acid in phosphate buffer solution was used to detect thiophene using a time-current method with a bias voltage of -0.4 to 0 V.

[0015] The beneficial effects achieved by this invention are as follows: This invention constructs a high-performance photoelectrochemical sensor for the detection of thiophene based on a designed and synthesized photoelectrochemical molecule. In the presence of thiophene, the thiophene specifically reacts with the photoelectrochemical probe molecule, altering its structure and properties, thereby significantly increasing the photocurrent response. This sensor exhibits excellent specificity for thiophene and a fast response speed (less than 5 min). Under optimized conditions, the detection limit reaches 1.35 nmol·L⁻¹. -1 . Attached Figure Description

[0016] Figure 1 The proton NMR spectrum of the photoelectric probe for detecting thiophene prepared in this invention; Figure 2 The fabrication process of the photoelectrochemical sensor for detecting thiophenol prepared in this invention and the photocurrent response with thiophenol are shown in the schematic diagram. Figure 3 Infrared spectrum (A) and X-ray energy spectrum (B) of the photoelectrochemical sensor for detecting thiophenol prepared in this invention; Figure 4 The image shows the response of the photoelectric chemical sensor for detecting thiophenol in this invention after treatment with thiophenol solutions of different concentrations. The horizontal axis represents time, and the vertical axis represents the current value. Figure 5 This is a standard curve graph of the photoelectrochemical sensor for different concentrations of thiophenol, showing the linear relationship between the change in photocurrent and the logarithm of the thiophenol concentration; the horizontal axis represents the logarithm of the thiophenol concentration, and the vertical axis represents the photocurrent value. Figure 6 The graph shows the results of the selective test of benzenethiophenol by the photoelectrochemical sensor; the horizontal axis represents the interfering ions tested, and the vertical axis represents the photocurrent value. Detailed Implementation

[0017] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0018] Example 1 Preparation of photoelectric probe for detecting thiophenol (1) Dissolve 6-hydroxy-2-naphthaldehyde (0.344 g, 2 mmol), 2,4-dinitrofluorobenzene (0.372 g, 2 mmol) and K2CO3 (0.343 g, 2.5 mmol) in 10 mL of anhydrous acetonitrile, and heat at 80 °C. o The reaction was refluxed at C for 4 h. After the reaction was completed, the solution was filtered under reduced pressure and purified by column chromatography to obtain intermediate product A. (2) Intermediate product A (0.338 g, 1.0 mmol), 4-pyridineacetonitrile (0.118 g, 1.0 mmol), and piperidine (0.1 mL) were added to anhydrous ethanol (10 mL), and the mixture was refluxed at 80 °C for 8 h. After the reaction was completed, the solvent was removed by vacuum filtration, and the product was purified by column chromatography to obtain the product. The structure of the photoelectric probe (Dye-TP) for detecting thiophene is shown in the figure below. It is a yellow solid (0.315 g, 72%). The proton NMR spectrum is shown below. Figure 1 As shown, the description of this spectrum is as follows: 1 ¹H NMR (400MHz, DMSO) δ 8.95 (s, 1H), 8.73 (d, J = 4.2 Hz, 2H), 8.57 (s, 1H), 8.54–8.44 (m, 2H), 8.22 (d, J = 8.1 Hz, 2H), 8.09 (d, J = 8.5 Hz, 1H), 7.85 (s, 1H), 7.80 (s, 2H), 7.56 (d, J = 8.3 Hz, 1H), 7.39 (d, J = 9.2 Hz, 1H). MS: m / z, Theoretical value: [M+H] + 439.1; Measured value: 439.1; .

[0019] Example 2 Preparation of a photoelectrochemical sensor for detecting thiophenol: (1) Pretreatment of conductive glass (FTO) is performed, and the specific steps are as follows: (i) Immerse the conductive glass in concentrated sulfuric acid and sonicate for 30 minutes; (ii) Sonicate with ethanol for 30 minutes to remove any organic impurities that may be present on the surface of the conductive glass; (iii) Sonicate the glass three times with deionized water for 30 minutes each time, and then put the conductive glass into a vacuum drying oven to dry for later use.

[0020] (2) Measure 30 mL of deionized water and 30 mL of concentrated hydrochloric acid into a beaker and mix them. Then add 1.2 g of sodium chloride and stir thoroughly until the sodium chloride dissolves. Then add 1 mL of tetrabutyl titanate and stir again until the solution is clear and transparent. (3) Place the FTO pretreated in step (1) with the conductive side facing down into the mixed solution in step (2), and then place it in the inner liner of the polytetrafluoroethylene high-pressure reactor. Seal the reactor and place it in a 160℃ forced-air drying oven for 10 hours. After the reaction is complete, allow it to cool naturally to room temperature. Rinse the impurities on the surface of TiO2 with deionized water and then dry it. After drying, place it in a muffle furnace and heat it to 450℃ at a rate of 2℃ / min. Hold it for 30 min and then cool it to room temperature to obtain FTO / TiO2. (4) Add the photoelectric probe (1 mM) for detecting thiophenol prepared in Example 1 and (3-bromopropyl)trimethoxysilane (0.5 mM) to 10 mL of dry acetonitrile. After dissolving, place the FTO / TiO2 substrate in this solution and reflux for 5 h. After the reaction is complete, rinse with dimethyl sulfoxide (DMSO) and deionized water to remove the dye adsorbed on the electrode to obtain the photoelectric chemical sensor for detecting thiophenol (FTO / TiO2 / Dye-TP). The fabrication process of the photoelectrochemical sensor (FTO / TiO2 / Dye-TP) for detecting thiophenol and the schematic diagram of its photocurrent response to thiophenol are shown in the figure below. Figure 2 As shown, the infrared and X-ray energy dispersive spectroscopy characterization of the photoelectrochemical sensor for detecting thiophenol is as follows: Figure 3 As shown.

[0021] Example 3 Photoelectrochemical detection of thiophene Using the FTO / TiO2 / Dye-TP prepared in Example 2 as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum wire as the counter electrode, a photoelectrochemical detection system for mercury ions was assembled. The working electrode was then subjected to different concentrations of thiophene solutions (the concentrations of thiophene added from a to m were 0, 10 nmol·L⁻¹, and 10 nmol·L⁻¹, respectively). -1 50 nmol·L -1 100 nmol·L -1 500 nmol·L -1 1 μmol·L -12.5 μmol·L -1 5 μmol·L -1 10 μmol·L -1 20 μmol·L -1 30 μmol·L -1 40 μmol·L -1 50 μmol·L -1 The solution system contains 0.1 mol·L⁻¹ -1 Ascorbic acid in phosphate buffer (pH 7.4, 10 mmol·L⁻¹) -1 The aqueous solution of the substance was treated, and its photoelectrochemical response was tested. The results are as follows: Figure 4 As shown, by Figure 4 It can be seen that the response current increases continuously with the increase of thiophene concentration. A plot of photocurrent value against the logarithm of thiophene concentration is shown. 2+ Concentration at 10 nmol·L -1 – 10.0 μmol·L -1 Within a certain range, the two exhibit a good linear relationship. Figure 5 Therefore, quantitative detection of thiophene within this concentration range can be achieved. The selectivity of FTO / TiO2 / Dye-TP was tested; FTO / TiO2 / Dye-TP was effective for 50 μmol·L⁻¹. -1 Different interfering objects (F - Cl - ,Br - I - SO4 2- SO3 2- CO3 2- NO3 - Urea, AcO - The photocurrent response of aniline, cysteine ​​(Hcy), glutathione (GSH), and cysteine ​​(Cys) is as follows: Figure 6 As shown in the figure, the photoelectrochemical sensor is not affected by other common interfering substances and still has good selectivity and sensitivity for thiophenol.

Claims

1. A photoelectrochemical sensor for detecting thiophenol, characterized in that, Including photoelectric probes for detecting thiophenol; The photoelectric probe structure for detecting thiophenol is as follows: ， The preparation method of the photoelectrochemical sensor for detecting thiophenol is as follows: titanium dioxide is synthesized hydrothermally on FTO conductive glass to obtain FTO / TiO2. FTO / TiO2 is placed in a solution containing silane coupling reagent and photoelectric probe for detecting thiophenol and heated under reflux to react, thus obtaining the photoelectrochemical sensor for detecting thiophenol. The silane coupling reagent is: , where R is selected from any alkyl chain with 1 to 18 carbon atoms, n is an integer from 0 to 18, and X is F, Cl, Br or I.

2. A method for preparing a photoelectrochemical sensor for detecting thiophenol as described in claim 1, characterized in that, Includes the following steps: (1) Dissolve 6-hydroxy-2-naphthaldehyde and 2,4-dinitrofluorobenzene in an organic solvent, add alkali, and heat to react to obtain intermediate product A; (2) Add intermediate product A, 4-pyridine acetonitrile and coupling catalyst to an organic solvent and heat to react to obtain a photoelectric probe for detecting thiophenol; (3) Titanium dioxide was hydrothermally synthesized on FTO conductive glass to obtain FTO / TiO2. FTO / TiO2 was placed in a solution containing silane coupling reagent and photoelectric probe for detecting thiophenol and heated under reflux to obtain a photoelectric chemical sensor for detecting thiophenol. The silane coupling reagent mentioned in step (3) is: , where R is selected from any alkyl chain with 1 to 18 carbon atoms, n is an integer from 0 to 18, and X is F, Cl, Br or I.

3. The method for preparing the photoelectrochemical sensor for detecting thiophenol according to claim 2, characterized in that, The organic solvent mentioned in step (1) is one of dichloromethane, acetonitrile, N,N-dimethylformamide, and tetrahydrofuran, and the base is one of sodium carbonate, potassium carbonate, and cesium carbonate. The reaction temperature is 40~120℃ and the reaction time is 1~24h. The organic solvent mentioned in step (2) is one of methanol, ethanol, acetonitrile, and tetrahydrofuran, and the coupling catalyst is one or more of piperidine, acetic acid, and sodium acetate. The reaction temperature is 60~100℃ and the reaction time is 1~24h.

4. The method for preparing the photoelectrochemical sensor for detecting thiophenol according to claim 2, characterized in that, In step (1), the molar ratio of 6-hydroxy-2-naphthaldehyde, 2,4-dinitrofluorobenzene, and base is 2:2:2.5; in step (2), the molar ratio of intermediate product A and 4-pyridineacetonitrile is 1:

1.

5. The method for preparing the photoelectrochemical sensor for detecting thiophenol according to claim 2, characterized in that, The hydrothermal synthesis method of FTO / TiO2 is as follows: FTO conductive glass is placed in a reaction solution composed of water, concentrated hydrochloric acid, sodium chloride, and tetrabutyl titanate. The reaction temperature is controlled at 150~200℃ and the reaction time is 4~20h for hydrothermal reaction. After the reaction is completed, the glass is dried and calcined at high temperature to obtain FTO / TiO2.

6. The method for preparing the photoelectrochemical sensor for detecting thiophenol according to claim 5, characterized in that, The ratio of sodium chloride, tetrabutyl titanate, concentrated hydrochloric acid, and deionized water used in step (3) is 0.8~1.2 g: 0.2-1.0 mL: 25~35 mL: 25~35 mL; The concentration of the concentrated hydrochloric acid is 36%~38%; The high-temperature calcination conditions are as follows: the temperature is increased to 450℃ at a rate of 2℃ / min and held for 30 min.

7. The method for preparing the photoelectrochemical sensor for detecting thiophenol according to claim 2, characterized in that, The molar ratio of the silane coupling reagent to the photoelectric probe for detecting thiophenol is 2:1, and the reflux reaction time is 5 hours.

8. The application of the photoelectrochemical sensor for detecting thiophenol as described in claim 1 in the detection of thiophenol, characterized in that, An electrochemical workstation was used for testing with a three-electrode system. The photoelectrochemical sensor for detecting thiophenol was used as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum wire electrode as the counter electrode. The test solution contained 0.01–1 mol·L⁻¹ of... -1 Ascorbic acid in phosphate buffer solution was used to detect thiophene using a time-current method with a bias voltage of -0.4 to 0 V.

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