Molecularly imprinted modified electrode for detecting trifluoroacetic acid in water as well as preparation method and application of molecularly imprinted modified electrode

Abstract

The invention discloses a molecular imprinting modified electrode for detecting trifluoroacetic acid in water, a preparation method and application, an integrated composite sensing interface is constructed, the integrated composite sensing interface comprises an enrichment layer, a recognition layer and a conducting layer, single-layer Ti3C2Tx is adopted as the conducting layer, a three-dimensional conductive network is constructed, and the electron transfer rate is remarkably increased; a molecularly imprinted polymer is adopted as a conversion layer, a pre-designed specific recognition cavity can accurately capture target molecules, and the specific binding behavior of trifluoroacetic acid is converted into a detectable electrochemical signal; uiO-66-F4 is adopted as an enrichment layer, trifluoroacetic acid molecules in a water sample are efficiently enriched on an electrode interface by means of fluorine affinity interaction among fluorine atoms, the lower detection limit of the trifluoroacetic acid molecules is greatly reduced, and the detection limit can be as low as 6.94 ng / L. The molecularly imprinted modified electrode has the characteristics of good selectivity, good anti-interference capability, good repeatability, reduction of the detection cost of a single sample, realization of sensitive and rapid detection of trifluoroacetic acid under a complex water body condition, and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical detection and sensing, and particularly relates to a molecular imprinting modified electrode for detecting trifluoroacetic acid in water, a preparation method and an application thereof. Background Art

[0002] Per- and polyfluoroalkyl substances (PFASs) encompass thousands of synthetic fluorinated compounds. These substances are widely used, extremely persistent, and have the potential to bioaccumulate, making them ubiquitous in water systems worldwide. As long-chain PFASs (e.g., perfluorooctanoic acid) are phased out under regulatory pressure, ultra-short-chain PFASs, such as trifluoroacetic acid (TFA), now dominate environmental PFAS concentrations. Unlike hydrophobic long-chain PFASs, which primarily adsorb on sediments, the acidic and hydrophilic properties of trifluoroacetic acid (TFA) predispose it to rapid leaching, migration, and accumulation in aquatic ecosystems. However, due to its high carbon-fluorine bond dissociation energy, TFA is difficult to degrade naturally. Studies have found increasing concentrations of TFA in various environmental media, and in some regions, TFA concentrations in drinking water are approaching or exceeding the total PFAS limit (0.5 μg / L) set out in the draft EU Drinking Water Directive.

[0003] Current studies have shown that trifluoroacetic acid (TFA) can adversely affect human health and the environment. Therefore, the development of portable on-site detection methods that can selectively distinguish TFA from other interfering compounds in complex water matrices is crucial for assessing exposure risks and guiding remediation strategies.

[0004] At present, the detection and analysis technology of trifluoroacetic acid mainly relies on liquid / gas chromatography or fluorine nuclear magnetic resonance spectroscopy. However, these technologies are expensive and require professional laboratories and trained technicians to operate. Existing trifluoroacetic acid detection methods also include ultra-high performance liquid chromatography-tandem mass spectrometry, spectrophotometry, and ion exchange liquid chromatography-tandem mass spectrometry. Although the above methods are effective, they are often interfered with, time-consuming and costly. Therefore, it is urgent to develop a simpler, faster, more sensitive and selective detection method.

[0005] Molecularly imprinted electrodes are highly selective. By modifying the imprinted polymer, they can accurately measure target ions in trace environments. At the same time, they are low in cost and highly practical.

[0006] Emerging sensing strategies, such as colorimetry and fluorescence, show great potential for on-site detection of trifluoroacetic acid, but existing research has largely focused on sensing gaseous trifluoroacetic acid. Therefore, there is an urgent need to develop a rapid, portable, user-friendly, and low-cost method for the detection of trifluoroacetic acid in natural waters, capable of continuous monitoring. In this context, electrochemical sensing technology presents a promising alternative. Among various electrochemical sensing methods, pulsed electrochemical techniques, such as differential pulse voltammetry and square wave voltammetry, have been widely used in pollutant detection due to their excellent sensitivity and rapid analytical capabilities.

[0007] Due to the excellent stability of the carbon-fluorine bond in trifluoroacetic acid, it exhibits significant electrochemical inertness at conventional operating potentials, making it impossible to directly generate a detectable signal using traditional voltammetry (such as differential pulse voltammetry and square wave voltammetry). Therefore, it is imperative to develop new strategies that can effectively overcome this inertness and achieve highly sensitive detection. In addition, the composition of water bodies in the natural environment is complex, and achieving highly selective recognition of trifluoroacetic acid is another major challenge facing its detection. In order to simultaneously address the electrochemical inertness of trifluoroacetic acid and the selectivity problem in complex matrices, the present invention provides a molecularly imprinted modified electrode for detecting trifluoroacetic acid in water, a preparation method, and its application. Summary of the Invention

[0008] In response to the problems existing in the prior art, the present invention aims to provide a molecularly imprinted modified electrode for detecting trifluoroacetic acid in water, as well as its preparation method and application. The present invention constructs an integrated composite sensing interface (enrichment layer-recognition layer-conduction layer) that utilizes a fluorinated metal-organic framework (UiO-66-F4) to efficiently enrich trifluoroacetic acid molecules through fluorophilic interactions between fluorine atoms. The introduced molecularly imprinted polymer (MIP) provides precise complementary spatial recognition sites to achieve specific capture and signal conversion of trifluoroacetic acid. Furthermore, the highly conductive single-layer Ti3C2T x The construction of a fast electron conduction network greatly improves the sensitivity of the sensor. This multi-level collaborative design effectively overcomes the electrochemical inertness and environmental interference of trifluoroacetic acid molecules, significantly reducing the detection limit. In order to achieve the above object, the present invention adopts the following technical solutions: A first aspect of the present invention provides a method for preparing a molecularly imprinted modified electrode for detecting trifluoroacetic acid in water, comprising the following steps: Synthesis of S1 and UiO-66-F4: Tetrafluoroterephthalic acid (TFBDC) and zirconium nitrate tetrahydrate (Zr(NO3)4) were dissolved in a water / glacial acetic acid mixture and refluxed. The reaction product was sequentially soaked in anhydrous methanol and anhydrous dichloromethane and dried in vacuum to obtain UiO-66-F4. S2, molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x Synthesis of: Trifluoroacetic acid and methacrylic acid were dissolved in acetonitrile for pre-assembly; UiO-66-F4, single-layer Ti3C2T x , azobisisobutyronitrile and ethylene glycol dimethacrylate, nitrogen was introduced to carry out polymerization reaction, centrifuged, washed with methanol / glacial acetic acid mixture to remove template molecules, and dried to obtain the molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x ; S3、UiO-66-F4 / MIP@Ti3C2T x Preparation of molecularly imprinted modified electrodes: Molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x Dissolved in ultrapure water / ethanol mixed solvent, ultrasonically mixed, and the mixed solution was dropped on the electrode surface to obtain UiO-66-F4 / MIP@Ti3C2T x Molecularly imprinted modified electrodes.

[0009] Preferably, in step S1, the usage ratio of tetrafluoroterephthalic acid (TFBDC) and zirconium nitrate tetrahydrate (Zr(NO3)4) is 0.65-0.70 g: 1.30-1.40 g.

[0010] Preferably, in step S1, the volume ratio of water to glacial acetic acid in the water / glacial acetic acid mixture is 3-4:2. Preferably, in step S1, the reflux reaction temperature is 105-115° C., and the reaction time is 24-25 h.

[0011] Preferably, in step S1, the anhydrous methanol soaking treatment time is 70-75 hours, and the anhydrous dichloromethane soaking treatment time is 72-75 hours; the vacuum drying temperature is 115-125° C., and the drying time is 24-25 hours.

[0012] Preferably, in step S2, the trifluoroacetic acid, methacrylic acid, acetonitrile, UiO-66-F4, single-layer Ti3C2T x The dosage ratio of azobisisobutyronitrile and ethylene glycol dimethacrylate is 1.0~1.1mmol:4.0~4.2mmol:40~42mL:290~310mg:290~310mg:60~65mg:6.0~6.2mmol. Preferably, in step S2, the preassembly temperature is room temperature and the time is 12-13 hours; the polymerization reaction temperature is 63-67° C. and the reaction time is 12-13 hours; Preferably, in step S2, the nitrogen introduction time is 25 to 35 minutes; and the volume ratio of methanol to glacial acetic acid in the methanol / glacial acetic acid mixture is 6:1.

[0013] Preferably, in step S3, the volume ratio of water to ethanol in the water / ethanol mixed solvent is 1-3:1, and the ultrasonic mixing time is 2-3 hours.

[0014] Preferably, the drop-coating amount of the mixed solution is 20-25 μL. The second aspect of the present invention provides a molecularly imprinted modified electrode prepared by the above preparation method.

[0015] The third aspect of the present invention provides the use of the molecularly imprinted modified electrode in detecting trifluoroacetic acid in water.

[0016] The present invention has the following beneficial effects: (1) The present invention provides a molecularly imprinted modified electrode for detecting trifluoroacetic acid in water, and constructs an integrated composite sensing interface based on molecularly imprinted composite materials (including a fluorinated metal organic framework enrichment layer, a molecularly imprinted polymer recognition layer and a single layer of Ti3C2T x Conductive layer), in which a high-conductivity single-layer Ti3C2T x The research team used a molecularly imprinted polymer (MIP) as a conductive layer, constructing a three-dimensional conductive network that significantly increased the electron transfer rate. Its pre-designed specific recognition cavity, a molecularly imprinted polymer (MIP), served as a recognition layer, accurately captured target molecules and converted the specific binding behavior of trifluoroacetic acid into a detectable electrochemical signal. A fluorinated metal-organic framework (UiO-66-F4) was used as an enrichment layer, leveraging the fluorophilic interaction between fluorine atoms to efficiently enrich trifluoroacetic acid molecules in water samples at the electrode interface, significantly reducing the detection limit. Ultimately, the team achieved highly selective and sensitive on-site quantitative detection of trifluoroacetic acid in environmental water samples, with a detection limit as low as 6.94 ng / L. This approach addresses the bottlenecks of existing technologies, which suffer from insufficient sensitivity, poor selectivity, reliance on large, precision instruments, and the lack of portable on-site detection.

[0017] (2) The molecularly imprinted modified electrode provided by the present invention has good selectivity and anti-interference ability, as well as good repeatability, which reduces the detection cost of a single sample and realizes sensitive and rapid detection of trifluoroacetic acid under complex water conditions. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 SEM images of the materials prepared in Example 1: (a) molecularly imprinted polymer (MIP); (b) UiO-66-F4; (c) single-layer Ti3C2T x ; (d) Molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x ; Figure 2 Molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x EDS diagram; Figure 3 For: (a) UiO-66-F4, UiO-66-F4@Ti3C2T x , MIP and UiO-66; (b) UiO-66-F4, Ti3C2T x and UiO-66-F4@Ti3C2T x (c) X-ray photoelectron spectroscopy of fluorinated metal organic framework (UiO-66-F4) and non-fluorinated metal organic framework (UiO-66); Figure 4 (a) Different materials (UiO-66, UiO-66-F4, Ti3C2T x 、UiO-66-F4@Ti3C2T x ) EIS Nyquist plot of the corresponding electrode; (b) UiO-66-F4@Ti3C2T x Charge density difference diagram of different materials (UiO-66, UiO-66-F4, UiO-66-F4@Ti3C2T) in 0.5 mM potassium ferricyanide solution x 、UiO-66-F4@Ti3C2T x ) Tafel slope results of the corresponding electrodes; (d) UiO-66-F4@Ti3C2T x Charge density difference results of the upper probe; Figure 5 (a) UiO-66-F4 / MIP@Ti3C2T x Response current changes of the molecularly imprinted modified electrode after incubation in trifluoroacetic acid solutions with different concentrations; (b) Fitting curve of the current response to trifluoroacetic acid concentration; Figure 6 UiO-66-F4 / MIP@Ti3C2T x Selective detection results of trifluoroacetic acid by molecularly imprinted modified electrode; Figure 7 UiO-66-F4 / MIP@Ti3C2Tx Figure 3 shows the stability test results of molecularly imprinted modified electrode for trifluoroacetic acid detection. DETAILED DESCRIPTION

[0019] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0020] Example 1 A method for preparing a molecularly imprinted modified electrode for detecting trifluoroacetic acid in water comprises the following steps: (1) Single-layer Ti3C2T x Preparation of Ti3AlC2 was etched at 35°C for 24 hours using concentrated hydrochloric acid: ultrapure water: hydrofluoric acid = 6:3:1 by volume. The bottom precipitate was collected and washed by centrifugation multiple times to make the pH of the precipitate greater than 6. Anhydrous lithium chloride of equal weight was added for 14 hours of intercalation. The supernatant collected was the single-layer Ti3C2T x ; (2) Synthesis of UiO-66-F4: Dissolve 0.69g of tetrafluoroterephthalic acid (TFBDC) and 1.354g of zirconium nitrate tetrahydrate (Zr(NO3)4) in 50mL of a water / glacial acetic acid mixture (volume ratio 3:2). Reflux at 110°C for 24 hours. The reaction product is then soaked in anhydrous methanol for 72 hours (with the solvent changed every 24 hours), then treated with anhydrous dichloromethane for 72 hours. Finally, vacuum dry at 120°C for 24 hours to obtain a white powder, UiO-66-F4. (3) Molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x Synthesis of: 1.0 mmol trifluoroacetic acid and 4.0 mmol methacrylic acid were dissolved in 40 mL acetonitrile and preassembled for 12 h. 300 mg UiO-66-F4 and 300 mg single-layer Ti3C2T4 were added to the system. x , 62 mg of azobisisobutyronitrile and 6.0 mmol of ethylene glycol dimethacrylate, nitrogen was introduced for 30 min to remove oxygen in the solution, and then the solution was transferred to a 65 ° C water bath for polymerization for 12 h. The precipitate was collected by centrifugation and washed with a methanol / glacial acetic acid mixture (6:1, v / v) to remove the template molecules. After drying, a black-gray powder was obtained, namely the molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x ; (4) UiO-66-F4 / MIP@Ti3C2T x Preparation of molecularly imprinted modified electrodes: The molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x Dissolved in ultrapure water / ethanol mixed solvent (3:1, v / v), ultrasonically mixed for 2 h to obtain a mixed solution, and 20 μL of the mixed solution was dropped on the electrode surface to obtain UiO-66-F4 / MIP@Ti3C2T x Molecularly imprinted modified electrodes.

[0021] Electrochemical testing conditions: The electrolyte solution consisted of a mixture of 0.1 M potassium chloride, 5 mM potassium ferrocyanide, and 0.1 M phosphate buffered saline (PBS), with a pH of 7. Before testing, the electrolyte solution was purged with nitrogen for 15 minutes to eliminate the effects of dissolved oxygen. For environmental water samples, pretreatment included 0.22 μm filtration followed by solid-phase extraction. Standard addition calibration was performed using spike concentrations ranging from 100 to 1000 ng / L to account for matrix effects. For differential pulse voltammetry (DPV) testing, the potential window was set to 0 V to 0.4 V. Electrochemical impedance spectroscopy (EIS) was performed on a CHI660e electrochemical workstation with a frequency range of 0.1 Hz to 500 kHz. Linear sweep voltammetry (LSV) and Tafel analysis were performed within a potential window of -0.8 V to 0.8 V, and the Tafel slope was used to compare the catalytic rates of the materials.

[0022] 1. Characterization of materials (1) Morphological and structural characterization Figure 1 (a) Molecularly imprinted polymers (MIPs) are uniform spherical particles (approximately 150 nm in diameter) with clear molecular cavities. Figure 1 (b) UiO-66-F4 monomer particles are characterized by a nanostructure composed of stacked porous particles, which form an open framework that is conducive to analyte diffusion. Figure 1 (c) shows a single layer Ti3C2T x The original two-dimensional layered morphology of the nanosheets; Figure 1 (d) shows the molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x The morphology of the Ti3C2T x In the layer, a dense mixed structure is formed, and Ti3C2T x The surface still retains a clear layered structure, indicating that the Ti3C2T x The appearance was not destroyed. (2) EDS characterization Figure 2 Molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x The EDS diagram of Figure 2 The results clearly show that the Ti3C2T x The Ti element mapping of the monolayer Ti3C2T4 and the Zr and F element mapping of UiO-66-F4 prove that UiO-66-F4 (fluorinated metal organic framework) is uniformly distributed in the monolayer Ti3C2T4. x surface.

[0023] (3) Infrared spectroscopy characterization Depend on Figure 3 (a) Results of molecular imprinting composite materials UiO-66-F4 / MIP@Ti3C2T x Successfully synthesized by Figure 3 (b) Result judgment UiO-66-F4@Ti3C2T x Successful synthesis; Figure 3 (c) is the X-ray photoelectron energy spectrum of the fluorinated metal organic framework (UiO-66-F4) and the non-fluorinated metal organic framework (UiO-66). The F element peak in the spectrum can be used to determine whether the fluorination is successful.

[0024] 2. Electrochemical performance Figure 4 (a) The results show that the charge transfer resistance (R ct ) are 457.9Ω and 238.2Ω respectively, and the R ct is significantly lower, which is related to its unique band structure characteristics. x The combination with UiO-66-F4 makes R ct The performance of UiO-66-F4@Ti3C2T was significantly reduced to 148.8Ω, indicating that the x The conductivity is improved.

[0025] In order to clarify the charge transfer mechanism at the interface, the present invention also conducted Bader charge analysis, and the results are shown in Figure 4 (b). Figure 4 (b) The results obtained from Ti3C2T x The net electron transfer to UiO-66-F4 is 8.11e - , this charge redistribution establishes an interfacial electric field, thereby promoting charge transfer between components.

[0026] The electrode sensitivity was further quantified using Tafel slope analysis, and the results are shown in Figure 4 (c).

[0027] Depend on Figure 4 (c) The results show that UiO-66, UiO-66-F4, UiO-66-F4@Ti3C2T x and UiO-66-F4 / MIP@Ti3C2T x The Tafel slopes of UiO-66-F4@Ti3C2T are 973.76, 805.61, 125.91 and 203.12 mV / dec respectively. x The heterostructures exhibit the highest sensitivity, and this enhanced kinetic behavior is directly related to the interfacial electronic structure.

[0028] Figure 4 (d) Charge density difference analysis results show that [Fe(CN)6] 3- / 4- The redox probe preferentially adsorbs on UiO-66-F4@Ti3C2T x Ti3C2T in materials x On the titanium atom of the component, the net charge transfer from Ti atom to N atom was found to be 2.85e - , indicating that the probe promotes electron acceptance. Therefore, UiO-66-F4@Ti3C2T x The significant improvement in electrode sensitivity is attributed to the accelerated interfacial charge transfer process, which is enabled by the unique electronic coupling within the heterostructure architecture. 3. Analytical performance and linearity of the electrode for trifluoroacetic acid.

[0029] UiO-66-F4 / MIP@Ti3C2T x The molecularly imprinted modified electrode was placed in trifluoroacetic acid solution with different concentration gradients (0μM~13mM) and the current response change was detected after incubation. The test results are as follows: Figure 5 (a) shown.

[0030] Depend on Figure 5 (a) The results show that with the increase of trifluoroacetic acid concentration, the response current gradually decreases. This may be because more trifluoroacetic acid binds to the sites on the molecularly imprinted polymer, blocking the redox of potassium ferrocyanide / potassium ferrocyanide probe on the electrode surface. The results show that UiO-66-F4 / MIP@Ti3C2T x Molecularly imprinted modified electrodes -4 ~10 -8 There is linearity within the range.

[0031] The current response under different trifluoroacetic acid concentration gradients was plotted against the corresponding trifluoroacetic acid concentration to obtain a linear fitting curve. Figure 5 (b)

[0032] Figure 5(b) The fitting results show that the response current has a good linear relationship with the concentration of trifluoroacetic acid, R 2 =0.993. The good linear performance can be attributed to the following reasons: (1) The single-layer Ti3C2T x As a conductive layer, it greatly improves the electron mobility; (2) The fluorinated metal organic framework acts as an enrichment layer to effectively enrich trifluoroacetic acid, thereby improving the detection accuracy; (3) The molecularly imprinted polymer selectively binds to trifluoroacetic acid molecules, thereby improving the sensitivity of electrode detection.

[0033] 4. Electrode selectivity for trifluoroacetic acid Add acetic acid, pentafluoropropionic acid, heptafluorobutyric acid, perfluorooctanoic acid and a mixed solution containing all substances and trifluoroacetic acid at a concentration ten times that of trifluoroacetic acid to the solution, and measure the peak current difference before and after adding the interfering substances. The results are shown in Figure 6 .

[0034] Depend on Figure 6 The results show that the presence of other interfering substances does not lead to large fluctuations before and after the peak current. The good selectivity of the electrode proves that the molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T synthesized in this invention x It has good selectivity for trifluoroacetic acid. 5. Stability testing Depend on Figure 7 The results show that the detection of trifluoroacetic acid by using three sets of parallel electrodes in four tests with three days intervals each time shows that the difference in the response current of the electrode is small under the long-term storage of 12 days, proving that UiO-66-F4 / MIP@Ti3C2T x The molecularly imprinted modified electrode has good stability.

[0035] 6. Detection and analysis of trifluoroacetic acid in actual water samples Tap water and Xiangjiang River water (diluted 1000 times) were selected for testing. The UiO-66-F4 / MIP@Ti3C2T prepared in Example 1 was x The molecularly imprinted electrode was used for the quantitative determination and spike recovery of trifluoroacetic acid in real water samples (tap water and Xiangjiang River water). The test results are shown in Table 1 below.

[0036] Table 1

[0037] The results in Table 1 show that the recovery rate of the material in actual water is between 96.42% and 108.66%. After repeated tests, the RSD of the test results is below 10%, indicating that the UiO-66-F4 / MIP@Ti3C2T prepared by the present invention is xThe molecularly imprinted modified electrode is feasible for the detection of trifluoroacetic acid in actual water samples with good reproducibility and has great application potential.

[0038] The present invention is not limited to the above-mentioned specific implementation methods. Various changes made by ordinary technicians in this field based on the above-mentioned concept without creative work are all within the scope of protection of the present invention.

Claims

1. A method for preparing a molecularly imprinted modified electrode for detecting trifluoroacetic acid in water, characterized in that: The following steps are involved: Synthesis of S1 and UiO-66-F4: Tetrafluoroterephthalic acid and zirconium nitrate tetrahydrate were dissolved in a water / glacial acetic acid mixture and refluxed. The reaction product was sequentially soaked in anhydrous methanol and anhydrous dichloromethane, and vacuum dried to obtain UiO-66-F4. S2, molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x Synthesis of: Trifluoroacetic acid and methacrylic acid were dissolved in acetonitrile for pre-assembly; UiO-66-F4, single-layer Ti3C2T x , azobisisobutyronitrile and ethylene glycol dimethacrylate, nitrogen was introduced to carry out polymerization reaction, centrifuged, washed with methanol / glacial acetic acid mixture to remove template molecules, and dried to obtain the molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x ; S3、UiO-66-F4 / MIP@Ti3C2T x Preparation of molecularly imprinted modified electrodes: Molecularly imprinted composite material UiO-66-F4 / MIP@Ti3C2T x Dissolved in ultrapure water / ethanol mixed solvent, ultrasonically mixed, and the mixed solution was dropped on the electrode surface to obtain UiO-66-F4 / MIP@Ti3C2T x Molecularly imprinted modified electrodes.

2. The method for preparing a molecularly imprinted modified electrode according to claim 1, wherein In step S1, the ratio of tetrafluoroterephthalic acid to zirconium nitrate tetrahydrate is 0.65-0.70 g: 1.30-1.40 g; the reflux reaction temperature is 105-115° C., and the reaction time is 24-25 h.

3. The method for preparing a molecularly imprinted modified electrode according to claim 1, wherein In step S1, the anhydrous methanol soaking treatment time is 70-75 hours, and the anhydrous dichloromethane soaking treatment time is 72-75 hours; the vacuum drying temperature is 115-125° C., and the drying time is 24-25 hours.

4. The method for preparing a molecularly imprinted modified electrode according to claim 1, wherein In step S2, the trifluoroacetic acid, methacrylic acid, acetonitrile, UiO-66-F4, single-layer Ti3C2T x The dosage ratio of azobisisobutyronitrile and ethylene glycol dimethacrylate is 1.0~1.1mmol:4.0~4.2mmol:40~42mL:290~310mg:290~310mg:60~65mg:6.0~6.2mmol.

5. The method for preparing a molecularly imprinted modified electrode according to claim 1, wherein In step S2, the preassembly temperature is room temperature and the time is 12-13 hours; the polymerization reaction temperature is 63-67° C. and the reaction time is 12-13 hours.

6. The method for preparing a molecularly imprinted modified electrode according to claim 1, wherein In step S3, the volume ratio of water to ethanol in the water / ethanol mixed solvent is 1-3:1, and the ultrasonic mixing time is 2-3 hours.

7. A molecularly imprinted modified electrode for detecting trifluoroacetic acid in water, characterized in that: Prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the molecularly imprinted modified electrode as claimed in claim 7 in detecting trifluoroacetic acid in water.

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