An ion selective electrode for detecting perchlorate and a preparation method thereof

Abstract

The invention discloses an ion selective electrode for detecting perchlorate and a preparation method thereof. The invention first synthesizes a perchlorate ion carrier, specifically dichlorophosphorus tetraphenylporphyrin, using a pyridine solution of tetraphenylporphyrin, POCl3, and PCl5 as raw materials; then dichlorophosphorus tetraphenylporphyrin, an ion exchanger, specifically tetraoctylammonium chloride, polyvinyl chloride, polytetrafluoroethylene, and a plasticizer, specifically dibutyl phthalate, as raw materials, after a mixed reaction, the resulting reaction product is coated on the surface of an Mxene modified electrode to obtain an Mxene / ISE membrane electrode; finally, an Mxene / ISE membrane / Mxene‑py electrode is prepared. The results show that the composite electrode assembled with the electrode as an ion selective electrode has extremely strong selectivity for perchlorate, and at the same time, the response time is extremely fast, and sensitive and rapid detection of perchlorate under complex water conditions can be achieved. The ion selective electrode prepared by the present invention has the characteristics of low detection limit, strong anti-interference ability, and low cost in detecting perchlorate.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical detection, and particularly relates to an ion selective electrode for detecting perchlorate and a preparation method thereof. Background Art

[0002] Perchlorate is an inorganic ion that is easily soluble in water, non-volatile, and persistent in the environment. It can combine with potassium, sodium, calcium, and a variety of ions including ammonium to form compounds. Due to its good solubility and stability in water, perchlorate easily contaminates surface water and groundwater and is widely present in natural water sources. In addition, based on these characteristics, perchlorate is also commonly found in many agricultural and animal products.

[0003] Although perchlorate has good solubility and can be quickly excreted from the body, due to its ionic radius similar to that of iodide ions, perchlorate ions can reversibly replace iodine in thyroid receptors, thereby reducing the secretion of T3 and T4 hormones and seriously affecting thyroid function.

[0004] At present, the detection methods of perchlorate include mass spectrometry, spectrophotometry, ion chromatography, Raman spectroscopy, etc. Among them,

[0005] Ion chromatography: It is the most common method for perchlorate detection in laboratories and one of the most commonly used methods for detecting perchlorate. Ion chromatography separates ions in the sample through an ion exchange column and then uses a detector (such as a conductivity detector) for quantitative detection. It is an efficient, sensitive and reliable method to analyze perchlorate and other ion substances. The detection limit for perchlorate can reach 10μg / L, but it has disadvantages such as long detection time (>30min) and the need for sample pretreatment.

[0006] Spectrophotometry: Spectrophotometry uses perchlorate to react with specific reagents to generate colored products, and then uses a UV-visible spectrometer to measure the absorbance for quantitative analysis. However, the sensitivity is relatively low, and the selectivity is low, making it difficult to apply to samples with complex background conditions.

[0007] Raman spectroscopy: Raman spectroscopy is a quantitative analysis method that detects the Raman scattering spectrum of perchlorate molecules under laser irradiation. This method has the advantages of being fast, non-destructive and highly sensitive, but it requires expensive instruments and equipment and is difficult to adapt to the requirements of large-scale samples and online detection.

[0008] Mass spectrometry: Mass spectrometry is based on the measurement of the motion trajectory and mass-to-charge ratio of ions in an electric field, combined with a mass analyzer to separate and detect these ions. Perchlorate is usually detected and analyzed in the form of molecular ions or their fragment ions in mass spectrometry. Mass spectrometry has a low detection limit for perchlorate, but mass spectrometry equipment is expensive, detection costs are high, and operation is complicated.

[0009] Although the above methods are effective, they are susceptible to interference, time-consuming, and costly. Summary of the invention

[0010] In view of the problems existing in the prior art, the present invention aims to provide an ion selective electrode for detecting perchlorate and a preparation method thereof.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A first aspect of the present invention provides a method for preparing an ion selective electrode for detecting perchlorate, comprising the following steps:

[0013] S1. Preparation of tetraphenylporphyrin dichlorophosphine chloride, i.e., perchlorate ion carrier:

[0014] Under a protective gas atmosphere, tetraphenylporphyrin is dissolved in pyridine, and POCl3 is added under stirring to obtain a mixture; PCl5 is dissolved in pyridine, and then added to the mixture for reflux reaction; the reflux reaction product is separated and purified to obtain dichlorophosphodiphenylporphyrin chloride;

[0015] S2. Preparation of Mxene modified electrode:

[0016] The monolayer Mxene is dissolved in ultrapure water, and the obtained monolayer Mxene aqueous solution is drop-coated on the electrode surface to prepare the Mxene modified electrode;

[0017] S3. Preparation of Mxene / ISE membrane electrode:

[0018] Tetraphenylporphyrin dichlorophosphine chloride, tetraoctylammonium chloride, polyvinyl chloride, polytetrafluoroethylene and dibutyl phthalate are dissolved in tetrahydrofuran, and stirred at room temperature for reaction. After the reaction is completed, the obtained reaction product is drop-coated on the surface of the Mxene modified electrode and dried to obtain a Mxene / ISE membrane electrode with a double-layer structure.

[0019] S4. Preparation of brominated alkylpyridine compounds:

[0020] Pyridine and bromoalkane are added to DMF, mixed evenly, allowed to stand for reaction, and then excess water is added to precipitate, which is filtered to obtain bromoalkylpyridine (R-py, hereinafter referred to as py);

[0021] S5. Preparation of Mxene / ISE membrane / Mxene-py electrode:

[0022] Bromoalkylpyridine and monolayer Mxene are dispersed in ultrapure water, mixed and stirred to obtain a mixed solution, and the mixed solution is drop-coated on the surface of the Mxene / ISE membrane electrode with a double-layer structure in batches to prepare a Mxene / ISE membrane / Mxene-py modified electrode with a sandwich structure, i.e., the target ion selective electrode.

[0023] Preferably, in step S1, the dosage ratio of tetraphenylporphyrin, POCl3 and PCl5 is 0.1~0.15g:2~3ml:0.1~0.15g.

[0024] Preferably, in step S1, the reflux time is 18 to 28 hours.

[0025] Preferably, in step S2, the concentration of the monolayer Mxene aqueous solution is 1.3-3 mg / ml.

[0026] Preferably, in step S2, the preparation steps of the single-layer MXene are: placing Ti3AlC2 in a mixed solution of concentrated hydrochloric acid, ultrapure water, and hydrofluoric acid in a volume ratio of 6:3:1, etching at 30-40°C for 20-28h, collecting the bottom precipitate, centrifuging, and washing so that the pH of the precipitate is greater than 6; adding lithium chloride to the precipitate for intercalation, shaking by hand until the bottom precipitate expands, centrifuging, and collecting the supernatant, which is the single-layer MXene.

[0027] Preferably, the mass amount of Ti3AlC2 and lithium chloride is the same.

[0028] Preferably, in step S3, the dosage ratio of tetraphenylporphyrin dichlorophosphine chloride, tetraoctylammonium chloride, polyvinyl chloride, polytetrafluoroethylene, and dibutyl phthalate is 1-1.5 mg: 0.6-0.8 mg: 30-35 mg: 0.2-0.4 mg: 60-70 mg.

[0029] Preferably, in step S3, the stirring reaction time is 2 to 3 hours.

[0030] Preferably, in step S4, the dosage ratio of pyridine and alkyl bromide is 0.8-0.9 g: 1-1.5 ml.

[0031] Preferably, in step S4, the temperature of the static reaction is 80-100° C., and the reaction time is 18-24 h.

[0032] Preferably, in step S5, the ratio of the brominated alkylpyridine to the monolayer Mxene is 1-1.5 g: 500-600 mg.

[0033] Preferably, in step S5, the stirring and mixing time is 2 to 3 hours.

[0034] The second aspect of the present invention is to provide an ion selective electrode prepared by the above preparation method.

[0035] The third aspect of the present invention is to provide a method for detecting perchlorate using the above-mentioned ion selective electrode, comprising the following steps:

[0036] A1. Assemble the composite electrode: insert the Mxene / ISE membrane / Mxene-py electrode as the working electrode and the Ag / AgCl reference electrode into the corresponding cavity of the composite electrode shell, connect the ion meter, and assemble the composite electrode;

[0037] A2. Insert the assembled composite electrode into a series of perchlorate standard solutions with different known concentrations, measure the potential value, and draw a linear fitting curve based on the perchlorate concentration and potential value;

[0038] A3. Place the composite electrode in the water sample solution to be tested, and perform the measurement under the same conditions as in step A2. Substitute the measured potential into the linear fitting curve to obtain the concentration of perchlorate in the water sample to be tested.

[0039] Detection mechanism:

[0040] The invention firstly uses a pyridine solution of tetraphenylporphyrin, POCl3 and PCl5 as raw materials to synthesize a perchlorate ion carrier, specifically tetraphenylporphyrin dichlorophosphate; then uses tetraphenylporphyrin dichlorophosphate, an ion exchanger, specifically tetraoctylammonium chloride, polyvinyl chloride, polytetrafluoroethylene and a plasticizer, specifically dibutyl phthalate, as raw materials, and applies a reaction product obtained after a mixed reaction on the surface of an Mxene modified electrode to prepare an Mxene / ISE membrane electrode; finally, an Mxene / ISE membrane / Mxene-py electrode is prepared. Among them, the brominated alkylpyridine in the enhanced enrichment layer (Mxene-py) can adsorb perchlorate through electrostatic and hydrophobic effects to achieve the effect of concentration enrichment; the conversion layer (ISE) is prepared by synthesizing perchlorate ion carrier film. After the perchlorate adsorbed by the enhanced enrichment layer contacts the conversion layer, it will selectively bind to the perchlorate ion carrier, which will cause a change in the surface potential of the perchlorate conversion layer. The concentration of perchlorate is detected by detecting the change in potential; the single layer of Mxene in the transduction layer (Mxene) can greatly improve the overall conductivity of the electrode material and improve the sensitivity of detection.

[0041] Beneficial effects:

[0042] (1) The present invention prepares an ion carrier with high selective recognition ability for perchlorate, and combines it with Mxene with bromoalkylpyridine adsorbed on the surface to prepare a Mxene / ISE membrane / Mxene-py material with a sandwich structure, and applies the material as a modifying material to the electrode surface to obtain an Mxene / ISE membrane / Mxene-py electrode, i.e., an ion selective electrode, which is then assembled into a composite electrode (shell) together with a reference electrode, and can achieve strong selective and sensitive recognition of perchlorate, with a detection limit of up to 58.2μg / L. Experimental results show that the composite electrode assembled with the Mxene / ISE membrane / Mxene-py electrode as an ion selective electrode has extremely strong selectivity for perchlorate, and at the same time has an extremely fast response time (~17s), so it can achieve sensitive and rapid detection of perchlorate under complex water conditions.

[0043] (2) The method for detecting perchlorate of the present invention has the characteristics of wide linear detection range, low detection limit, strong anti-interference ability, simple operation, high efficiency and speed, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0045] Figure 1 is the nuclear magnetic resonance spectrum of dichlorophosphine tetraphenylporphyrin chloride, i.e., perchlorate ion carrier, obtained in Example 1;

[0046] Figure 2 SEM images of different electrode modification materials: (a) single layer Mxene; (b) Mxene / ISE membrane; (c) Mxene / ISE membrane / Mxene-py;

[0047] Figure 3 (a)SEM image of Mxene / ISE membrane / Mxene-py: (b)Mapping of Ti element; (c)Mapping of N element;

[0048] Figure 4 (a) R of the fitting curve obtained when preparing ion carrier membranes with different plasticizer ratios 2 Results; (b) R of the fitting curve obtained when the ion carrier membrane prepared with different ion exchanger ratios was tested 2 Results; (c) R of the fitting curve obtained when preparing ion carrier membranes at different ion carrier ratios 2 Result graph;

[0049] Figure 5 is a schematic diagram of the structure of the composite electrode;

[0050] Figure 6 The following are: (a) the potential response result of the composite electrode assembled with Mxene / ISE membrane / Mxene-py electrode as the working electrode when different concentrations of perchlorate are added; (b) the fitting curve of the potential response result to the concentration of perchlorate;

[0051] Figure 7 The selectivity diagram of the composite electrode assembled with Mxene / ISE membrane / Mxene-py electrode as the working electrode for perchlorate detection;

[0052] Figure 8 The stability result diagram of the composite electrode assembled with Mxene / ISE membrane / Mxene-py electrode as the working electrode for perchlorate detection;

[0053] Markings in the figure: 1. working electrode cavity; 2. reference electrode cavity; 3. electrode cap; 4. filled microporous ceramic. DETAILED DESCRIPTION

[0054] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0055] Example 1

[0056] A method for preparing an ion selective electrode for detecting perchlorate, comprising the following steps:

[0057] S1. Preparation of tetraphenylporphyrin dichlorophosphine chloride, i.e., perchlorate ion carrier:

[0058] Under argon, 0.12 g of tetraphenylporphyrin was dissolved in 20 ml of pyridine, and 2 ml of POCl3 was added dropwise under stirring to obtain a mixture; 0.12 g of PCl5 was dissolved in 3 ml of pyridine, and then added to the above mixture, refluxed for 24 h, cooled to room temperature, and pyridine was evaporated in vacuo to obtain a dark green solid; the dark green solid was dissolved in 60 ml of CH2Cl2, washed with distilled water to remove residual pyridine, the organic layer was separated, CH2Cl2 was evaporated, and then column chromatography was performed on alumina with CH2Cl2 / methanol as eluent, separated, and evaporated to dryness to obtain a green solid product, dichlorophosphodiphenylporphyrin, and its NMR results are shown in Figure 1 .

[0059] S2. Preparation of Mxene modified electrode:

[0060] At 35°C, Ti3AlC2 was etched with concentrated hydrochloric acid, ultrapure water and hydrofluoric acid in a volume ratio of 6:3:1 for 24 hours, and then the bottom precipitate was collected and washed by centrifugation multiple times to make the precipitate pH greater than 6, and then an equal weight of lithium chloride (LiCl) was added for intercalation, and the bottom precipitate was shaken by hand until it expanded, and the supernatant was collected by centrifugation to be the monolayer Mxene; 2.5 mg of the monolayer Mxene was dissolved in 1.2 ml of ultrapure water, and then 18 μL of the monolayer Mxene aqueous solution was dripped on the electrode surface to prepare the Mxene modified electrode;

[0061] S3. Preparation of Mxene / ISE membrane electrode:

[0062] 1.2 mg of tetraphenylporphyrin dichlorophosphine chloride, 0.8 mg of tetraoctylammonium chloride, 35 mg of polyvinyl chloride, 0.2 mg of polytetrafluoroethylene and 66 mg of dibutyl phthalate were dissolved in 3 ml of tetrahydrofuran, stirred at room temperature for 2 h to obtain a clear solution, 50 μL of the clear solution was drop-coated on the surface of the Mxene modified electrode, and dried to obtain a Mxene / ISE membrane electrode with a double-layer structure;

[0063] S4. Synthesis of brominated alkylpyridine:

[0064] 0.9 g of pyridine and 1.2 mL of bromoalkane were added to DMF (45-50 mL), mixed evenly, and allowed to react at 90° C. for 24 h. Then, an excess of water was added to precipitate, and the precipitate was filtered to obtain bromoalkylpyridine (R-py, hereinafter referred to as py);

[0065] S5. Preparation of Mxene / ISE membrane / Mxene-py electrode:

[0066] 1.2 g of alkyl bromide pyridine and 550 mg of single-layer Mxene were dispersed in 10 ml of ultrapure water, mixed and stirred for 3 h to obtain a mixed solution. 25 μL of the obtained mixed solution was drop-coated on the surface of the Mxene / ISE membrane electrode with a double-layer structure in batches to obtain a Mxene / ISE membrane / Mxene-py electrode with a sandwich structure, i.e., the target ion selective electrode.

[0067] 1. Characterization of materials

[0068] The dichlorophosphodiphenylporphyrin chloride, i.e., the perchlorate ion carrier, obtained in Example 1 was characterized by nuclear magnetic resonance. Figure 1 . Figure 1 The hydrogen peaks at different positions shown in the results demonstrate the successful synthesis of perchlorate ionophores.

[0069] The electrode modification materials (single-layer Mxene; Mxene / ISE membrane; Mxene / ISE membrane / Mxene-py) prepared in Example 1 were characterized by SEM. Figure 2 and Figure 3 .

[0070] Figure 2 (a) The emergence of the layered structure in the results proves the successful synthesis of monolayer MXene; Figure 2 (b) The results show that the surface of the Mxene / ISE membrane is smooth; Figure 2 (c) and Figure 3 (a) The results clearly show that in the Mxene / ISE membrane / Mxene-py electrode modified material, the Mxene surface after alkyl bromide pyridine intercalation still retains a clear layered structure, which indicates that the morphology of the Mxene surface is not destroyed after alkyl bromide pyridine intercalation.

[0071] (2) Energy dispersive X-ray spectroscopy (EDS) characterization

[0072] The electrode modification material Mxene / ISE membrane / Mxene-py prepared in Example 1 was characterized by EDS. Figure 3 .

[0073] Depend on Figure 3 (b) and Figure 3 (c) The results show that in the Mxene / ISE membrane / Mxene-py electrode modified material, the Ti element mapping representing Mxene and the N element mapping representing bromoalkylpyridine can be clearly seen, which proves that bromoalkylpyridine is uniformly distributed on the surface of Mxene.

[0074] (3) Optimization of the detection conditions of the present invention

[0075] The Mxene / ISE membrane electrode was prepared by changing the proportion of the perchlorate ion carrier, i.e., tetraphenylporphyrin dichlorophosphate, tetraoctyl ammonium chloride as an ion exchanger, and dibutyl phthalate as a plasticizer used in the preparation of the Mxene / ISE membrane electrode in step S3, and the composite electrode was assembled using the final Mxene / ISE membrane / Mxene-py modified working electrode, and the composite electrode was probed into the perchlorate solution for detection. The results are shown in FIG. Figure 4 .

[0076] Figure 4 (a) To optimize the preparation parameters of dibutyl phthalate as a plasticizer, experiments were conducted by selecting different doses of plasticizer to prepare ion carrier membranes. The results clearly showed that when the plasticizer accounted for 55%, the R of the material fitting curve was 2and slope K are optimal, which enables the electrode modification material to achieve the best detection effect. Similarly, Figure 4 (b) and Figure 4 In (c), the dosage of ion exchanger (specifically tetraoctyl ammonium chloride) and ion carrier was optimized, and the results showed that the best effect could be achieved when the ratio of ion exchanger to ion carrier was 1.5% and 1% respectively.

[0077] (4) Analytical performance of modified electrodes

[0078] Reference Figure 5 , design and manufacture a composite electrode: the composite electrode comprises a working electrode cavity 1, a reference electrode cavity 2, an electrode cap 3 and a filled microporous ceramic 4, the Mxene / ISE membrane / Mxene-py electrode prepared in Example 1 is inserted into the corresponding cavity as a working electrode and an Ag / AgCl reference electrode, and then connected to an ion meter. After the composite electrode is assembled, the composite electrode is probed into different concentrations (10 -5.3 M, 10 -5 M, 10 -4 M, 10 -3 M, 10 -2 M, 10 -1 M) perchlorate solution, record the electrode potential corresponding to different perchlorate concentrations, and detect perchlorate by fitting the potential data under different perchlorate concentrations. Figure 6 .

[0079] Depend on Figure 6 (a) The results show that as the concentration of perchlorate increases, the potential on the electrode surface gradually decreases. This may be due to the adsorption of more perchlorate on the electrode surface, which leads to a decrease in the electrode surface potential. The results also show that the potential response of the composite electrode assembled by Mxene / ISE membrane / Mxene-py modified electrode to detect perchlorate is at a concentration of 10 - 5.3 M~10 -1 There may be a good linear relationship within the range of M. By plotting the potential response at different concentrations against the corresponding perchlorate concentration, a linear fitting curve is obtained ( Figure 6 (b)), y=-55.21x+83.49, R 2=0.996. This indicates that the Mxene / ISE membrane / Mxene-py modified electrode has a wide linear range and a low detection limit. The reasons may be as follows: (1) In the electrode modification material, using a single layer of Mxene as a transduction layer can greatly improve the electron mobility; 2. In the electrode modification material, the perchlorate ion carrier can selectively bind to perchlorate to achieve the conversion of perchlorate signals; 3. In the electrode modification material, Mxene uniformly loaded with bromoalkylpyridine can play a good role in enriching perchlorate, greatly improving the detection accuracy of perchlorate.

[0080] (5) Electrode selectivity for perchlorate, i.e., anti-interference analysis

[0081] Since various interfering substances may exist in the water detection process, which may affect the detection results, 5 equivalents of Br - 、NO3 - 、H2PO4 - 、CH3COO - 、SO4 2- , Cl - 、ClO2 - 、ClO3 - 、ClO4 - The anti-interference performance of the modified electrode was tested by measuring the potential difference before and after adding interfering ions. Figure 7 .

[0082] Depend on Figure 7 The results show that ClO4 - The addition of ions will cause a dramatic change in the electrode surface potential, while the presence of other interfering ions will not cause changes in the electrode surface potential, which indicates that the modified electrode material has a significant effect on ClO4 - It has good selectivity, which further proves that the perchlorate ion carrier (ion selective electrode) synthesized by the present invention has good selectivity for perchlorate.

[0083] (6) Stability of modified electrode for perchlorate detection

[0084] Depend on Figure 8 The results show that the electrode has a good stability in terms of potential change when exposed to perchlorate over a 15-day storage period.

[0085] (7) Detection and analysis of actual water samples

[0086] In order to test the application potential of the material in actual water bodies, tap water, Xiangjiang River water and fireworks factory wastewater were selected for testing. The test results are shown in Table 1 below.

[0087] Table 1

[0088]

[0089] From the results in Table 1, it can be seen that the recovery rate of the material in actual water bodies is between 95.90% and 101.08%. After repeated tests, the RSD of the test results is below 3.71%, indicating that the material effect is stable, which means that the modified electrode is feasible for detecting perchlorate in actual water samples, with good reproducibility and great application potential.

[0090] The present invention is not limited to the above-mentioned specific implementation modes. Various changes made by ordinary technicians in this field based on the above-mentioned concepts without creative work are all within the protection scope of the present invention.

Claims

1. A method for preparing an ion selective electrode for detecting perchlorate, characterized in that: The following steps are involved: S1. Preparation of dichlorophosphine tetraphenylporphyrin chloride: Under a protective gas atmosphere, tetraphenylporphyrin is dissolved in pyridine, and POCl3 is added under stirring to obtain a mixture; PCl5 is dissolved in pyridine, and then added to the mixture, and refluxed to obtain dichlorophosphodiphenylporphyrin chloride; S2. Preparation of Mxene modified electrode: The monolayer Mxene is dissolved in ultrapure water, and the obtained monolayer Mxene aqueous solution is drop-coated on the electrode surface to prepare the Mxene modified electrode; S3. Preparation of Mxene / ISE membrane electrode: Tetraphenylporphyrin dichlorophosphine chloride, tetraoctylammonium chloride, polyvinyl chloride, polytetrafluoroethylene and dibutyl phthalate are dissolved in tetrahydrofuran, and stirred at room temperature for reaction. After the reaction is completed, the obtained reaction product is drop-coated on the surface of the Mxene modified electrode and dried to obtain a Mxene / ISE membrane electrode with a double-layer structure. The dosage ratio of tetraphenylporphyrin dichlorophosphine chloride, tetraoctyl ammonium chloride, polyvinyl chloride, polytetrafluoroethylene, and dibutyl phthalate is 1-1.5 mg: 0.6-0.8 mg: 30-35 mg: 0.2-0.4 mg: 60-70 mg; S4. Preparation of brominated alkylpyridine compounds: Pyridine and bromoalkane are added into DMF, mixed evenly, and allowed to stand for reaction to obtain bromoalkylpyridine; S5. Preparation of Mxene / ISE membrane / Mxene-py electrode: Bromoalkylpyridine and monolayer Mxene are dispersed in ultrapure water, mixed and stirred to obtain a mixed solution, and the mixed solution is drop-coated on the surface of the Mxene / ISE membrane electrode with a double-layer structure in batches to prepare a Mxene / ISE membrane / Mxene-py modified electrode with a sandwich structure.

2. The method for preparing an ion selective electrode for detecting perchlorate according to claim 1, characterized in that: In step S1, the dosage ratio of tetraphenylporphyrin, POCl3 and PCl5 is 0.1-0.15 g: 2-3 mL: 0.1-0.15 g; and the reflux time is 18-28 h.

3. The method for preparing an ion selective electrode for detecting perchlorate according to claim 1, characterized in that: In step S2, the preparation steps of the single-layer MXene are: placing Ti3AlC2 in a mixed solution of concentrated hydrochloric acid, ultrapure water and hydrofluoric acid, etching at 30-40°C for 20-28h, collecting the precipitate, centrifuging and washing, so that the pH of the precipitate is greater than 6; adding lithium chloride to the precipitate for intercalation reaction at room temperature, shaking by hand until the bottom precipitate expands, centrifuging, and collecting the supernatant to obtain the single-layer MXene.

4. The method for preparing an ion selective electrode for detecting perchlorate according to claim 1, characterized in that: In step S2, the concentration of the monolayer Mxene aqueous solution is 1.3-3 mg / mL.

5. The method for preparing an ion selective electrode for detecting perchlorate according to claim 1, characterized in that: In step S3, the stirring reaction time is 2 to 3 hours.

6. The method for preparing an ion selective electrode for detecting perchlorate according to claim 1, characterized in that: In step S4, the dosage ratio of pyridine and bromoalkane is 0.8-0.9 g: 1-1.5 mL; the temperature of the static reaction is 80-100° C., and the reaction time is 18-24.

7. The method for preparing an ion selective electrode for detecting perchlorate according to claim 1, characterized in that: In step S5, the dosage ratio of the brominated alkylpyridine and the monolayer Mxene is 1-1.5 g: 500-600 mg; and the mixing and stirring time is 2-3 h.

8. An ion selective electrode for detecting perchlorate, characterized in that: Prepared by the preparation method according to any one of claims 1 to 7.

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