Fluorine-philic hydrophobic functional monomer, synthesis method and application thereof, detection electrode and preparation method thereof

Abstract

The invention relates to the technical field of organic chemistry and environmental science, in particular to a fluorine-philic and hydrophobic functional monomer, a synthesis method and application thereof, a fluorine-containing compound detection electrode based on the functional monomer and a preparation method of the fluorine-containing compound detection electrode. The chemical structure of the fluorine-philic and hydrophobic functional monomer comprises pyrrole-3-carboxylic acid and fluorine telomer alcohol bonded with the pyrrole-3-carboxylic acid. A long fluorocarbon chain is introduced into a basic functional monomer, so that the fluorine affinity and hydrophobicity of the monomer to a fluorine-containing compound are remarkably improved. Therefore, a derivative pyrrole-3-carboxylic acid of pyrrole is used as a basic functional monomer, and the fluorine telomeric alcohol is bonded on the pyrrole-3-carboxylic acid, so that a novel functional monomer with fluorine-philic and hydrophobic functions is synthesized. The functional monomer realizes specific capture of fluorine-containing organic matter molecules by simultaneously utilizing amido with affinity to perfluorinated compounds in a pyrrole ring and unique fluorine-fluorine interaction force. A perfluorinated compound detection method established based on the functional monomer can avoid interference caused by a sample matrix.

Description

Technical Field

[0001] The present invention relates to the field of organic chemistry and environmental science and technology, and in particular to a fluorine-philic and hydrophobic functional monomer and a synthesis method and application thereof, as well as a fluorine-containing compound detection electrode based on the functional monomer and a preparation method thereof. Background Art

[0002] Perfluorinated compounds (PFAS) are a class of fluorinated chemicals that are extremely chemically stable and corrosion-resistant and are widely used in industrial, firefighting, household and personal care products. Due to their environmental persistence and bioaccumulation, PFAS pose a serious threat to the environment and human health. For example, PFAS have been shown to have negative effects on the liver, immune system and reproductive system. Therefore, it is critical to accurately identify, adsorb, remove and detect perfluorinated compounds.

[0003] Currently, the main technology for detecting PFAS is liquid chromatography-mass spectrometry (LC-MS / MS), which is widely used in the detection of PFAS due to its high sensitivity and high specificity. However, LC-MS / MS equipment is expensive, complicated to operate, and requires a long analysis time, which limits its application in rapid on-site detection and large-scale screening. In this context, electrochemical technology, as an alternative, has become a research focus due to its advantages such as low cost, simple operation, and suitability for on-site detection.

[0004] In the field of electrochemical sensing, due to the electrochemical inertness of perfluorinated compounds, efficient identification and detection of perfluorinated compounds in different environmental media is a thorny problem. At present, molecular imprinted polymers (MIPs) are widely used to specifically identify PFAS. By synthesizing imprinted polymers with specific pore structures on conductive substrates, specific recognition of target molecules can be achieved. However, according to existing research, the recognition of perfluorinated compounds by MIPs mainly depends on the hydrogen bonding interaction provided by hydrophilic groups such as carboxyl or sulfonic acid groups at their terminals, or is captured by cationic recognition groups through electrostatic interactions in their ionic state (such as perfluorooctanoic acid, pKa≈3.7). However, these two interaction forces are ubiquitous in nature and can easily interfere with detection.

[0005] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a fluorine-philic and hydrophobic functional monomer and its synthesis method and application, a detection electrode and its preparation method, aiming to overcome the problem that the current reliance on hydrogen bonds or electrostatic interactions to identify, adsorb, remove and detect perfluorinated compounds is easily interfered by external factors, which makes it difficult to carry out practical applications.

[0007] The technical solution of the present invention is as follows:

[0008] A fluorine-loving and hydrophobic functional monomer comprises pyrrole-3-carboxylic acid and a fluorotelomer alcohol bonded to the pyrrole-3-carboxylic acid; the chemical structural formula of the fluorine-loving and hydrophobic functional monomer is as follows:

[0009] Wherein, n≥1 and is an integer.

[0010] The fluorine-philic and hydrophobic functional monomer, wherein the ratio of the carbon-fluorine chain length to the carbon-hydrogen chain length in the fluoropolyol is (6-12):2.

[0011] A method for synthesizing a fluorine-philic and hydrophobic functional monomer comprises the steps of:

[0012] Mixing pyrrole-3-carboxylic acid with an organic solvent to obtain a pyrrole-3-carboxylic acid solution;

[0013] Adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine to the pyrrole-3-carboxylic acid solution and stirring to obtain a mixed solution;

[0014] The mixed solution is mixed with fluoropolymer alcohol, and subjected to esterification reaction to obtain a fluorine-philic and hydrophobic functional monomer.

[0015] The method for synthesizing the fluorine-philic and hydrophobic functional monomers, wherein the molar ratio of the pyrrole-3-carboxylic acid to the fluoropolymer alcohol is (1-2):(1-2).

[0016] The method for synthesizing the fluorine-philic and hydrophobic functional monomer, wherein the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide to the 4-dimethylaminopyridine is (20-25):(1-2).

[0017] Application of a fluorine-philic and hydrophobic functional monomer in electrochemical detection of perfluorinated compounds.

[0018] A detection electrode comprises a conductive substrate and a F-pyrrole imprinted polymer layer arranged on the conductive substrate; the F-pyrrole imprinted polymer layer is obtained by in-situ polymerization of the fluorine-philic and hydrophobic functional monomers.

[0019] The detection electrode, wherein the conductive substrate includes one of a screen-printed electrode, a glassy carbon electrode, a carbon electrode, a gold electrode, and a platinum electrode.

[0020] A method for preparing a detection electrode comprises the steps of:

[0021] The fluorine-philic and hydrophobic functional monomers, the template molecules and the supporting electrolyte are mixed with the solvent, and after ultrasonic treatment and pH adjustment, a polymerization solution is obtained;

[0022] Immersing the conductive substrate in the polymerization solution and subjecting the substrate to electrochemical polymerization to obtain a modified conductive substrate;

[0023] The template molecules in the modified conductive substrate are eluted to obtain a detection electrode.

[0024] The method for preparing the detection electrode, wherein the template molecule includes one or more of perfluorononanoic acid, perfluoropentanesulfonic acid, perfluorooctanesulfonic acid, and perfluorooctanoic acid; and / or the supporting electrolyte includes one or more of tetrabutylammonium fluorosulfonate and lithium perchlorate.

[0025] Beneficial effects: The present invention provides a fluorine-loving and hydrophobic functional monomer and its synthesis method and application, a detection electrode and its preparation method. The fluorine-loving and hydrophobic functional monomer includes pyrrole-3-carboxylic acid and a fluoropolymer alcohol bonded to the pyrrole-3-carboxylic acid. The present invention can significantly improve the fluorine-loving and hydrophobic properties of the monomer to fluorine-containing compounds by introducing a long carbon fluorine chain into the functional monomer; using pyrrole-3-carboxylic acid, a derivative of pyrrole, as a skeleton functional monomer, the pyrrole ring contains an amine group with affinity for perfluorinated compounds, so that it has the ability to bind to perfluorinated compounds, and using fluoropolymer alcohol to directly bond to pyrrole-3-carboxylic acid to synthesize 3-[2-(perfluorooctyl)ethoxycarbonyl]pyrrole, referred to as F-pyrrole, that is, the fluorine-loving and hydrophobic functional monomer. At the same time, by changing the length of the carbon fluorine chain in F-pyrrole, it can also be used to regulate the affinity of the monomer to different perfluorinated compounds and its hydrophobicity. The obtained fluorine-philic and hydrophobic functional monomer utilizes unique fluorine-fluorine interaction forces to capture fluorine-containing organic molecules, avoiding interference with detection by other interaction forces, thereby achieving efficient processing capabilities for fluorine-containing compounds and ensuring their effectiveness and accuracy in environmental testing; in addition, the functional monomer can also be used for efficient processing of fluorine-containing compounds, thereby improving selectivity and removal efficiency in environmental analysis and pollutant removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the chemical reaction equation for synthesizing the fluorine-philic and hydrophobic functional monomers in Example 1 of the present invention;

[0027] Figure 2 The F-pyrrole obtained in Example 1 1 H NMR spectrum;

[0028] Figure 3 The F-pyrrole obtained in Example 1 19 F NMR spectrum;

[0029] Figure 4 is the mass spectrum of F-pyrrole obtained in Example 1;

[0030] Figure 5HPLC spectrum of F-pyrrole prepared in Example 1;

[0031] Figure 6 Schematic diagram of the electrochemical preparation of detection electrodes and their application in detecting PFNA in Example 1;

[0032] Figure 7 This is a data diagram of electropolymerization of F-pyrrole using cyclic voltammetry in Example 1;

[0033] Figure 8 This is the DPV current response data diagram of F-PIP@SPE after adding different concentrations of PFNA;

[0034] Fig. 9 A solid phase extraction column using F-pyrrole as an adsorbent and a diagram showing the removal effect of the solid phase extraction column on PFNA;

[0035] Fig.10 Transmission electron microscopy images of F-pyrrole using ethanol and water as solvents respectively;

[0036] Fig.11 This is a scanning electron microscope image;

[0037] Fig.12 This is the contact angle test diagram;

[0038] Fig.13 This is a comparison diagram of the restored DPV signal of the same F-PIP@SPE after use and the previous signal;

[0039] Fig.14 Comparison of the recovery and signal changes of three different F-PIP@SPEs after a single use;

[0040] Fig.15 The figure shows the number of times F-PIP@SPE is reused and its signal change diagram;

[0041] Fig.16 This is a graph showing the current signal changes of the same F-PIP@SPE after storage for 0 days, 5 days, 10 days, 15 days, and 30 days. DETAILED DESCRIPTION

[0042] The present invention provides a fluorine-philic and hydrophobic functional monomer and its synthesis method and application, a detection electrode and its preparation method. In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0043] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0044] A major feature that distinguishes perfluorinated compounds from other pollutants is that they are rich in carbon-fluorine (CF) bonds. Fluorine-fluorine interaction (FF interaction) is an interaction force that occurs between fluorinated compounds, and the energy of the fluorine-fluorine interaction force is approximately between 1 and 20 kcal / mol. The specific energy depends on the length of the carbon-fluorine chain, but there is no doubt that this is enough to allow fluorinated organic molecules to be captured by the fluorinated organic layer.

[0045] Based on this, the present invention provides a fluorophilic and hydrophobic functional monomer, comprising pyrrole-3-carboxylic acid and a fluorotelomer alcohol bonded to the pyrrole-3-carboxylic acid; the chemical structural formula of the fluorophilic and hydrophobic functional monomer is as follows:

[0046] Wherein, n≥1 and is an integer.

[0047] In this embodiment, by introducing a long carbon fluorine chain into the functional monomer, the fluorine affinity and hydrophobicity of the monomer to fluorinated compounds can be significantly improved; using pyrrole derivative pyrrole-3-carboxylic acid as a skeleton functional monomer, the pyrrole ring contains an amine group with affinity for perfluorinated compounds, so that it has the ability to bind perfluorinated compounds, and fluoropolyol (FTOH) is directly bonded to pyrrole-3-carboxylic acid to synthesize 3-[2-(perfluorooctyl)ethoxycarbonyl]pyrrole, referred to as F-pyrrole, i.e., the fluorine-affinity hydrophobic functional monomer. At the same time, it is also possible to change the length of the carbon fluorine chain in F-pyrrole to regulate the affinity of the monomer to different perfluorinated compounds, as well as its hydrophobicity. And the obtained fluorine-affinity hydrophobic functional monomer utilizes a unique fluorine-fluorine interaction force to achieve the capture of fluorinated organic molecules, avoiding interference with detection by other interaction forces, thereby achieving efficient processing capabilities for fluorinated compounds, ensuring its effect and accuracy in environmental detection.

[0048] In some embodiments, the ratio of the carbon fluoride chain length to the hydrocarbon chain length in the fluoropolyol is (6-12):2. By adjusting the ratio of the carbon fluoride chain length to the hydrocarbon chain length in the fluoropolyol, the affinity of the fluorophilic hydrophobic functional monomer to different perfluoro compounds and the hydrophobicity of the fluorophilic hydrophobic functional monomer can be adjusted. Specifically, the longer the carbon fluoride chain, the stronger the affinity for the perfluoro compound with the longer carbon fluoride chain length, and the stronger the hydrophobicity.

[0049] In a preferred embodiment, the ratio of the carbon fluorine chain length to the carbon hydrogen chain length in the fluorotelomer alcohol is 6:2 or 8:2.

[0050] Specifically, the fluoropolymer alcohol includes but is not limited to 8:2 perfluorodecyl alcohol and 6:2 perfluorodecyl alcohol.

[0051] In addition, the present invention also provides a method for synthesizing a fluorine-philic and hydrophobic functional monomer, comprising the steps of:

[0052] Step S10: mixing pyrrole-3-carboxylic acid with an organic solvent to obtain a pyrrole-3-carboxylic acid solution;

[0053] Step S20: adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine to the pyrrole-3-carboxylic acid solution and stirring to obtain a mixed solution;

[0054] Step S30: mixing the mixed solution with fluoropolymer alcohol, and subjecting the mixed solution to an esterification reaction to obtain a fluorophilic and hydrophobic functional monomer.

[0055] In the present embodiment, pyrrole-3-carboxylic acid is selected as the basic skeleton functional monomer, which can be used as a functional monomer for electrochemical polymerization reaction, and can be modified in situ on different substrate materials. Therefore, pyrrole-3-carboxylic acid is used to directly bond fluoropolymer alcohol to pyrrole-3-carboxylic acid through a one-step esterification reaction to synthesize 3-[2-(perfluorooctyl)ethoxycarbonyl]pyrrole (F-pyrrole). The amine group on the pyrrole ring in F-pyrrole has affinity for perfluoro compounds, providing the ability to bind perfluoro compounds, while the fluoropolymer alcohol bonded to pyrrole-3-carboxylic acid can form fluorine-fluorine interaction forces with perfluoro compounds, achieving specific capture of perfluoro compounds, and avoiding interference of other interaction forces with detection, thereby achieving efficient processing capabilities for fluorinated compounds, ensuring its high selectivity and accuracy in environmental detection. At the same time, the synthesis method of fluorophilic hydrophobic functional monomers is usually carried out at room temperature, the process is simple, the operation difficulty is low, and it is conducive to large-scale production.

[0056] Specifically, the synthesis method of the fluorophilic and hydrophobic functional monomer includes the following steps: dissolving pyrrole-3-carboxylic acid in a suitable organic solvent (such as acetonitrile), then adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine and stirring at room temperature until all the solutes are completely dissolved, then adding fluoropolymer alcohol, and continuing to stir the mixture for 24 hours to complete the esterification reaction; after the reaction is completed, removing the solvent, collecting the crude mixture, and washing the crude mixture with tetrabutylammonium fluorosulfonate (Milli-Q) water to remove unreacted substances and by-products, and then purifying the target product by silica gel column chromatography to obtain a light yellow powder solid fluorophilic and hydrophobic functional monomer.

[0057] In some embodiments, the molar ratio of the pyrrole-3-carboxylic acid to the fluorotelomer alcohol is (1-2):(1-2), which can make one of the raw materials excessive, improve the efficiency of the esterification reaction, and efficiently prepare the fluorophilic and hydrophobic functional monomer.

[0058] In a preferred embodiment, the molar ratio of the pyrrole-3-carboxylic acid to the fluorotelomer alcohol is 1:1, which can save raw material costs.

[0059] In some embodiments, the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide to the 4-dimethylaminopyridine is (20-25):(1-2). The 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and the 4-dimethylaminopyridine pyrrole-3-carboxylic acid solution are mixed according to the molar ratio, which is conducive to the subsequent esterification reaction of pyrrole-3-carboxylic acid with fluorotelomer alcohol to obtain a fluorophilic and hydrophobic functional monomer.

[0060] In a preferred embodiment, the molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide to the 4-dimethylaminopyridine is 25:2.

[0061] In addition, the present invention also provides an application of electrochemical detection of perfluorinated compounds based on fluorine-philic and hydrophobic functional monomers.

[0062] In this embodiment, the fluorophilic hydrophobic functional monomer can capture perfluoro compounds through the fluorine-fluorine interaction force between the monomer and the perfluoro compound, and the length of the carbon fluorine chain in the fluorophilic hydrophobic functional monomer can be adjusted according to the length of the carbon fluorine chain in the perfluoro compound, thereby adjusting the affinity of the fluorophilic hydrophobic functional monomer for different perfluoro compounds and its hydrophobicity, achieving efficient processing capabilities for fluorine-containing compounds, and ensuring its effectiveness and accuracy in environmental testing.

[0063] In some embodiments, the F-pyrrole can be used as an adsorbent and filled into a solid phase extraction column to prepare a solid phase extraction column for adsorbing and removing perfluorinated compounds.

[0064] In a preferred embodiment, the F-pyrrole is used as an adsorbent and glass microbeads are used as a filling layer to prepare a solid phase extraction column.

[0065] In addition, the present invention also provides a detection electrode, including a conductive substrate, and a F-pyrrole imprinted polymer layer disposed on the conductive substrate; the F-pyrrole imprinted polymer layer is obtained by in-situ polymerization of the fluorine-philic and hydrophobic functional monomers.

[0066] In this embodiment, the fluorophilic-hydrophobic functional monomer can be conveniently polymerized in situ on different conductive substrates by an electrochemical in situ method; the fluorophilic-hydrophobic functional monomer and the template molecule are used to directly synthesize a F-pyrrole imprinted polymer (F-PIP) layer on a conductive substrate by cyclic voltammetry, thereby achieving the effect of in situ detection of PFNA-containing contamination by utilizing the detection electrode's easy transportation and use characteristics and combining it with a micro electrochemical workstation.

[0067] In some embodiments, the conductive substrate includes but is not limited to one of a screen-printed electrode, a glassy carbon electrode, a carbon electrode, a gold electrode, and a platinum electrode. The present invention uses pyrrole-3-carboxylic acid as a basic functional monomer skeleton, which can undergo an electrochemical polymerization reaction, so that the fluorophilic and hydrophobic functional monomer can be directly in-situ modified on different substrate materials.

[0068] In a preferred embodiment, a screen-printed electrode is selected as the conductive substrate.

[0069] In addition, the present invention also provides a method for preparing a detection electrode, comprising the steps of:

[0070] Step S100: mixing the fluorine-philic and hydrophobic functional monomers, the template molecules and the supporting electrolyte with a solvent, and obtaining a polymerization solution after ultrasonic treatment and pH adjustment;

[0071] Step S200: immersing the conductive substrate in the polymerization solution, and performing electrochemical polymerization to obtain a modified conductive substrate;

[0072] Step S300: eluting the template molecules in the modified conductive substrate to obtain a detection electrode.

[0073] In this embodiment, the fluorophilic hydrophobic functional monomer can be conveniently polymerized in situ on different conductive substrates by an electrochemical in situ method; the fluorophilic hydrophobic functional monomer and the template molecule are used to synthesize the F-pyrrole imprinted polymer (Fluorinated-pyrrole imprinted polymer, F-PIP) directly on the conductive substrate by cyclic voltammetry, and after eluting the template molecule, a polymer layer with strong recognition ability for PFNA is finally obtained, and the detection electrode is convenient for transportation and use. In combination with a micro-electrochemical workstation, the effect of in-situ detection of pollution containing PFNA can also be achieved. In addition, the detection electrode modified with a fluorophilic hydrophobic functional monomer or a polymer modified with a fluorophilic hydrophobic functional monomer can extract, concentrate and enrich perfluorinated compounds in water samples, ensuring the efficient processing ability of the technology for perfluorinated compounds in water sample processing. In addition, the detection electrode can be used to electrochemically detect the concentration of perfluorinated compounds in different environmental media, and ensure its effect and accuracy in environmental detection.

[0074] Specifically, the preparation method of the detection electrode specifically includes the steps of: dissolving F-pyrrole and template molecules and supporting electrolytes in a suitable solvent (such as methanol-water solution, ethanol-water solution, acetonitrile-water solution, etc.), and performing ultrasonic treatment, then adding NH4OH to adjust the pH, and finally removing the gas in the solution with N2 gas to obtain a polymerization solution. The conductive substrate is connected to an electrochemical workstation and immersed in the above-mentioned polymerization solution, and then electropolymerization is performed using cyclic voltammetry (CV) to obtain a modified conductive substrate, which is thoroughly rinsed with water and dried under N2 gas flow; then the modified conductive substrate is immersed in an acetonitrile / methanol solvent containing NH4OH, and shaken at 30°C to completely remove PFNA, and then the electrode is rinsed with ultrapure water to remove the residual eluent, and gently blown dry with nitrogen, and finally the modified conductive substrate is placed in an oven and dried at 60°C for 10 minutes to remove any organic solvent adsorbed in the polymer coating to obtain a detection electrode.

[0075] In some embodiments, the template molecule comprises perfluorononanoic acid (PFNA, C8F 17 COOH), perfluoropentane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA); and / or the supporting electrolyte includes one or more of tetrabutylammonium fluorosulfonate and lithium perchlorate.

[0076] Specifically, the target analyte acts as a template molecule. After the polymer is synthesized, a specific method is required to elute the template molecule to obtain a molecular imprinting polymer having the same pore structure as the target analyte, namely, F-pyrrole imprinting polymer.

[0077] The following examples are further given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention.

[0078] Example 1

[0079] This embodiment provides a fluorine-philic and hydrophobic functional monomer and a detection electrode, and performs electrochemical detection on the monomer, including the following:

[0080] like Figure 1 As shown, the steps of synthesizing the fluorine-philic and hydrophobic functional monomer (i.e., 3-[2-(perfluorooctyl)ethoxycarbonyl]pyrrole, referred to as F-pyrrole) include:

[0081] 1) Add 5 mM pyrrole-3-carboxylic acid to 100 mL acetonitrile (MeCN) solution;

[0082] 2) Add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC, 5 mM) and 4-dimethylaminopyridine (DMAP, 0.4 mM) to the above solution;

[0083] 3) stirring the solution at room temperature for 30 minutes to ensure that pyrrole-3-carboxylic acid is completely dissolved;

[0084] 4) 8:2-perfluorodeoxycholesterol (8:2-FTOH, 5 mM) was then added and the mixture was stirred for 24 hours to complete the esterification reaction;

[0085] 5) After the reaction is completed, the solvent is removed and the crude mixture is collected. The crude mixture is washed with tetrabutylammonium fluorosulfonate (Milli-Q) water to remove unreacted substances and by-products; the target product is purified by silica gel column chromatography to finally obtain a light yellow powder solid (purity greater than 98%), namely F-pyrrole. The nuclear magnetic resonance hydrogen spectrum of F-pyrrole: δ H (400MHz,CDCl3)2.57(2H,tt,J=18.4,6.4Hz,H-10),4.55(2H,t,J=6.6Hz,H-9),6.67-6.68(1H,m,H-5),6.78(1H,q,J=2.4Hz,H-5),7.45-7.46(1H,m,H-3),8.53(1H,s,NH).,The hydrogen nuclear magnetic resonance spectrum of F-pyrrole is shown in Figure 2 As shown; NMR fluorine spectrum of F-pyrrole: δ F(377MHz,CDCl3)-126.07(2F,m),-123.51(2F,m),-122.69(2F,m),-121.89(4F,m),-121.61(2F,m),-113.50(2F,m),-80.744(3F,m). The NMR fluorine spectrum of F-pyrrole is as follows Figure 3 As shown; mass spectrometry and high performance liquid chromatography are shown Figure 4 and Figure 5 As shown in the figure, the relative molecular mass of the target product calculated from the mass spectrum of F-pyrrole is: MS (ESI) m / z = 556.8, and the theoretical relative molecular mass is 557.03, which are very close; according to the HPLC chromatogram, the peak area at the retention time of 2.726 accounts for 98.133% of the total peak area. This reveals that the purity of F-pyrrole after purification reaches >98%.

[0086] like Figure 6 and Figure 7 As shown, the steps of preparing the detection electrode include:

[0087] 1) 10 mM F-pyrrole (functional monomer), 5 mM PFNA (template molecule) and 10 mM NBu4PF6 (supporting electrolyte) were dissolved in 10 mL MeCN-H2O solution (8:2, v / v), and ultrasonically treated for 3 minutes, then 2 μL / mL NH4OH was added to adjust the pH, and finally N2 gas was used to remove gas from the solution for 10 minutes to prepare a polymerization solution;

[0088] 2) The screen printed electrode (SPE) was connected to an electrochemical workstation and immersed in the above polymerization solution, and electropolymerization was performed using cyclic voltammetry (CV). Figure 7 In order to use cyclic voltammetry (CV), F-pyrrole molecularly imprinted polymer ( Figure 7 a) and non-imprinted polymer ( Figure 7 b). Cyclic voltammetry shows the relationship between current and voltage. As the voltage increases, the current is stable between -0.3V and 0.4V, then rises sharply, and an oxidation peak appears around +0.9V, which can be attributed to the oxidation of the amine group. The current continues to rise after +0.9V, indicating that F-pyrrole is undergoing polymerization.

[0089] The CV parameters were set as follows: the potential range was -0.3 V to 1.2 V (Versus Ag), the scan rate was 50 mV / s, and 10 cycles were performed. The modified screen-printed electrode obtained, called F-PIP(PFNA)@SPE (the template molecule has not been removed at this time), was thoroughly rinsed with water and dried under a stream of N2; the F-PIP(PFNA)@SPE was immersed in acetonitrile containing 0.1% NH4OH at 30°C and shaken (100 rpm) for 15 minutes to completely remove PFNA, and then the electrode was rinsed with ultrapure water to remove the residual eluent and gently blown dry with nitrogen. Finally, the modified screen-printed electrode was placed in an oven and dried at 60°C for 10 minutes to remove any organic solvent adsorbed in the polymer coating. The obtained electrode is called F-PIP@SPE (i.e., the template has been removed) and can be stored under safe conditions without strict environmental control.

[0090] like Figure 6 As shown, the prepared F-PIP@SPE is subjected to electrochemical detection of PFNA, including the following steps:

[0091] 1) Connect the prepared F-PIP@SPE to the electrochemical workstation, then immerse it in aqueous solutions containing different PFNA concentrations and incubate for 15 minutes. Take it out, rinse the surface with clean water, and then blow dry with nitrogen;

[0092] 2) The incubated F-PIP@SPE was immersed in a supporting electrolyte, and the change of the current value was recorded by differential pulse voltammetry (DPV). The change of the DPV current of F-PIP@SPE in PFNA solutions with different concentrations is shown in the figure: Figure 8 As shown in the left figure;

[0093] 3) The supporting electrolyte composition is: 5 mM ferrocenecarboxylic acid, 2 μL / mL NH4OH and 1 μL / mL HCl;

[0094] 4) Differential pulse voltammetry was performed in the potential range of −0.1 V to 0.5 V (vs. Ag), using an amplitude of 25 mV and a pulse width of 0.025 s;

[0095] 5) Plot the change in current against the PFNA concentration to obtain a standard curve, such as Figure 8 As shown in the right figure;

[0096] 6) For PFNA solutions of unknown concentration, the concentration can be reversely calculated through the standard curve after measuring the current value.

[0097] Example 2

[0098] The F-pyrrole prepared in Example 1 is used as an adsorbent and filled into a solid phase extraction column to prepare a solid phase extraction column for adsorbing and removing perfluorinated compounds. Taking PFNA as an example, the wastewater containing PFNA is passed through the column, and the PFNA concentration in the filtrate is detected to evaluate the removal rate of PFNA by the column. In actual operation, due to the super hydrophobicity of F-pyrrole, the PFNA aqueous solution is not easy to pass through the F-pyrrole adsorption layer. Therefore, glass microbeads are added to the adsorption layer as a filler to increase the contact area between F-pyrrole and PFNA and improve the removal efficiency.

[0099] Specific as Fig. 9 As shown, F-pyrrole was used as the adsorbent and glass beads were used as the filling layer to prepare the solid phase extraction column. Fig. 9 As shown in the left figure, Fig. 9 The right figure shows the removal effect of the solid phase extraction column on PFNA; the detection of PFNA concentration is completed by LC-MS / MS.

[0100] Example 3

[0101] The F-pyrrole obtained in Example 1 was characterized by transmission electron microscopy. Fig.10 As shown in the figure, the characterization results show that when ethanol is used as the solvent, the morphology of F-pyrrole is regular spherical particles; when water is used as the solvent, the particle size increases significantly, reaching a maximum of 6μm, and shows an aggregated morphology. This shows that F-pyrrole prefers to dissolve in alcohol solvents and is not easily soluble in water.

[0102] Example 4

[0103] The modified electrodes (including F-PIP(PFNA)@SPE and F-PIP@SPE) prepared in Example 1 were characterized by scanning electron microscopy. Fig.11 As shown, Fig.11 a in the figure is a blank SPE, b is a SPE modified by F-pyrrole molecular imprinting polymer (containing PFNA), and c is a SPE modified by F-pyrrole molecular imprinting polymer (without PFNA). It can be found that after electropolymerization of F-pyrrole, the surface of the screen-printed electrode has changed significantly, and its particle size has increased significantly.

[0104] Example 5

[0105] The contact angle test of the modified electrode prepared in Example 1 was carried out. The results are as follows: Fig.12 As shown, Fig.12a in the figure is a blank SPE, b is an SPE modified with F-pyrrole molecular imprinting polymer (containing PFNA), and c is an SPE modified with F-pyrrole molecular imprinting polymer (excluding PFNA); on the blank electrode, the angle between the water droplet and the SPE surface is about 44.5 degrees; after modification with poly-F-pyrrole, the angle increases significantly to about 157 degrees. This indicates that the polymer layer is super hydrophobic. After removing PFNA, the angle drops slightly to about 140 degrees. This is because PFNA itself also has a certain degree of hydrophobicity.

[0106] Example 6

[0107] The robustness of the F-PIP@SPE prepared in Example 1 during detection was tested. Fig.13 The cycling stability of F-PIP@SPE was demonstrated. Fig.14 The changes in the detection performance of F-PIP@SPE after repeated use and different storage times were demonstrated. All test results showed that the sensor had good analytical performance and robustness.

[0108] Fig.15 The results show that the signal shows a large deviation after the sixth use, indicating that the F-PIP@SPE can be stably recycled for 6 times. Fig.16 The current signal changes of the same F-PIP@SPE after storage for 0 days, 5 days, 10 days, 15 days and 30 days.

[0109] In summary, the present invention provides a fluorine-loving and hydrophobic functional monomer and its synthesis method and application, detection electrode and preparation method thereof, wherein the fluorine-loving and hydrophobic functional monomer includes pyrrole-3-carboxylic acid and a fluoropolymer alcohol bonded to the pyrrole-3-carboxylic acid. The present invention can significantly improve the fluorine-loving and hydrophobic properties of the monomer to fluorinated compounds by introducing a long carbon fluorine chain into the functional monomer; using pyrrole-3-carboxylic acid, a derivative of pyrrole, as a skeleton functional monomer, the pyrrole ring contains an amine group with affinity for perfluorinated compounds, so that it has the ability to bind to perfluorinated compounds, and using fluoropolymer alcohol to directly bond to pyrrole-3-carboxylic acid to synthesize 3-[2-(perfluorooctyl)ethoxycarbonyl]pyrrole, referred to as F-pyrrole, that is, the fluorine-loving and hydrophobic functional monomer. At the same time, the length of the carbon fluorine chain in F-pyrrole can also be changed to regulate the affinity of the monomer to different perfluorinated compounds, as well as its hydrophobicity. The obtained fluorine-philic and hydrophobic functional monomers utilize unique fluorine-fluorine interaction forces to capture fluorine-containing organic molecules, avoiding interference with detection by other interaction forces, thereby achieving efficient processing capabilities for fluorine-containing compounds and ensuring their effectiveness and accuracy in environmental testing.

[0110] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A fluorine-philic and hydrophobic functional monomer, characterized in that: It includes pyrrole-3-carboxylic acid and a fluoropolymer alcohol bonded to the pyrrole-3-carboxylic acid; the chemical structural formula of the fluorine-philic and hydrophobic functional monomer is as follows: Wherein, n≥1 and is an integer.

2. The fluorine-philic and hydrophobic functional monomer according to claim 1, characterized in that: The ratio of the carbon fluorine chain length to the carbon hydrogen chain length in the fluoropolyol is (6-12):

2.

3. A method for synthesizing a fluorine-philic and hydrophobic functional monomer, characterized in that: Includes steps: Mixing pyrrole-3-carboxylic acid with an organic solvent to obtain a pyrrole-3-carboxylic acid solution; Adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 4-dimethylaminopyridine to the pyrrole-3-carboxylic acid solution and stirring to obtain a mixed solution; The mixed solution is mixed with fluoropolymer alcohol, and subjected to esterification reaction to obtain a fluorine-philic and hydrophobic functional monomer.

4. The method for synthesizing a fluorine-philic and hydrophobic functional monomer according to claim 3, characterized in that: The molar ratio of the pyrrole-3-carboxylic acid to the fluorotelomer alcohol is (1-2):(1-2).

5. The method for synthesizing a fluorine-philic and hydrophobic functional monomer according to claim 3, characterized in that: The molar ratio of the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide to the 4-dimethylaminopyridine is (20-25):(1-2).

6. Use of the fluorine-philic and hydrophobic functional monomer according to any one of claims 1 to 2 in electrochemical detection of perfluorinated compounds.

7. A detection electrode, characterized in that: It comprises a conductive substrate and an F-pyrrole imprinted polymer layer arranged on the conductive substrate; the F-pyrrole imprinted polymer layer is obtained by in-situ polymerization of the fluorophilic and hydrophobic functional monomers according to any one of claims 1 to 2.

8. The detection electrode according to claim 7, characterized in that: The conductive substrate includes one of a screen-printed electrode, a glassy carbon electrode, a carbon electrode, a gold electrode, and a platinum electrode.

9. A method for preparing a detection electrode as claimed in claim 7, characterized in that: Includes steps: The fluorine-philic and hydrophobic functional monomers, the template molecules and the supporting electrolyte are mixed with the solvent, and after ultrasonic treatment and pH adjustment, a polymerization solution is obtained; Immersing the conductive substrate in the polymerization solution and subjecting the substrate to electrochemical polymerization to obtain a modified conductive substrate; The template molecules in the modified conductive substrate are eluted to obtain a detection electrode.

10. The method for preparing a detection electrode according to claim 9, characterized in that: The template molecule includes one or more of perfluorononanoic acid, perfluoropentanesulfonic acid, perfluorooctanesulfonic acid, and perfluorooctanoic acid; and / or the supporting electrolyte includes one or more of tetrabutylammonium fluorosulfonate and lithium perchlorate.

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