Method for constructing a non-washing molecularly imprinted polymer membrane ion-selective electrode and application thereof

Abstract

The present application relates to ion selective electrode, specifically a kind of construction method and application of non-elution molecularly imprinted polymer membrane ion selective electrode. Specifically, non-elution template molecularly imprinted polymer is used as recognition carrier and is incorporated into polymer sensitive film dispersion liquid, then it is added on the electrode surface of ion-electron conducting layer modification, namely non-elution template imprinted polymer membrane ion selective electrode is obtained;Wherein, non-elution template imprinted polymer accounts for 4-8wt% of the weight of polymer sensitive film in dispersion liquid. The method not only greatly shortens the preparation time of potential type sensor based on molecularly imprinted polymer, but also improves the repeatability between batches of these sensors.

Description

Technical Field

[0001] This invention relates to ion-selective electrodes, specifically a method for constructing and applying a wash-free molecularly imprinted polymer membrane ion-selective electrode. Background Technology

[0002] Polymer membrane ion-selective electrodes have been widely used in the detection of environmental and biological samples due to their advantages such as simple preparation, low cost, high selectivity, and ease of on-site detection. However, the number of recognition carriers available for the detection of organic substances is limited. With the development of supramolecular science, the emergence of molecularly imprinted polymers has greatly changed this situation. Compared with traditional biorecognition molecules (antibodies and enzymes, etc.), they have similar affinity and selectivity, and also have advantages such as low cost, simple preparation methods, and stronger stability. In recent years, various polymer membrane potential sensors based on molecularly imprinted polymers as recognition carriers have been developed for the detection of various ionic and neutral organic substances, biomolecules, and other substances.

[0003] However, currently used molecularly imprinted polymers are synthesized in porogenic solvents in the presence of functional monomers, template molecules, and crosslinking agents. After the free radical polymerization reaction is complete, the polymer is typically washed multiple times in an eluent (such as methanol / acetic acid) for several hours each time to remove the template molecules.

[0004] Traditional Nernst-response-based molecularly imprinted polymer membrane potential sensors typically require template ion solution treatment before measurement. Template molecules can diffuse from the aqueous sample phase to the membrane phase, allowing the molecularly imprinted polymer in the sensitive membrane to recombine with the template molecules. Therefore, the aforementioned cumbersome and time-consuming template removal process is unnecessary, as a significant portion (approximately 85%) of the imprinted cavity cannot be reoccupied by the template and may even reduce electrode repeatability and the recognition efficiency of the molecularly imprinted polymer. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing analytical techniques and provide a method for preparing and applying a elution-free molecularly imprinted polymer membrane ion-selective electrode.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for constructing a wash-free molecularly imprinted polymer membrane ion-selective electrode involves incorporating a wash-free template-imprinted polymer as a recognition carrier into a polymer-sensitive membrane dispersion, and then dropping it onto the electrode surface modified with an ion-electron conduction layer to obtain a wash-free template-imprinted polymer membrane ion-selective electrode; wherein the wash-free template-imprinted polymer accounts for 4-8 wt% of the weight of the polymer-sensitive membrane in the dispersion.

[0008] The molecularly imprinted polymer that does not require washing to remove the template is produced by heating the template molecules in the presence of functional monomers, crosslinking agents, initiators and solvents to undergo a polymerization reaction, and then drying the template molecules for later use; wherein the template molecules, monomers and crosslinking agents are mixed in a molar ratio of 1:1-4:10-20.

[0009] The template-free molecularly imprinted polymer is obtained by mixing template molecules, monomers, and crosslinking agents, adding the mixture to a reaction solvent, mixing thoroughly, letting it stand for 30-60 minutes, purging with nitrogen for 10-30 minutes, quickly adding 25-50 mg of initiator, and thermally initiating polymerization at 60-80 degrees Celsius for 12-24 hours under sealed conditions to obtain a block polymer; then drying it in a vacuum drying oven.

[0010] The crosslinking agent is one or more of ethylene glycol dimethacrylate (EGDMA), trimethylolpropane trimethacrylate (TRIM), and divinylbenzene (DVB); the initiator is azobisisobutyronitrile (AIBN) or azobisisoheptanenitrile (ADVN); and the reaction solvent is acetonitrile, acetone, dichloromethane, trichloromethane, or tetrahydrofuran.

[0011] The template molecule is vancomycin, sulfadiazine, ciprofloxacin, or ceftiofur;

[0012] The monomer is acrylamide, methacrylic acid, or methyl methacrylate.

[0013] The polymer-sensitive membrane dispersion is composed of a polymer-sensitive membrane and a solvent, wherein the weight-to-volume ratio of the two is 80-100; wherein the polymer-sensitive membrane, by mass percentage, comprises 4-8 wt% no-wash template-removing molecularly imprinted polymer (MIP), 0.5-2 wt% tris(2-dimethylammonium chloride) chloride (TDMACl), 1-5 wt% tetra(4-chlorophenyl)borate tetra(2-dimethyl)ammonium salt (ETH500), 28.3-31.5 wt% polyvinyl chloride (PVC), and 57-63 wt% di-n-octyl phthalate (DOP); the solvent is tetrahydrofuran (THF).

[0014] The ion-electron conductive layer is formed by dispersing an ion-electron conductive material in deionized water to form a dispersion with a final concentration of 5-10 mg / mL, and then dropping the dispersion onto the surface of the electrode substrate to form the ion-electron conductive layer; wherein, the ion-electron conductive material is ordered mesoporous carbon, carbon nanotubes, nanoporous gold, polypyrrole, poly3-octylthiophene, or poly3,4-ethylenedioxythiophene.

[0015] The electrode substrate is a glassy carbon electrode.

[0016] An ion-selective electrode without washing and de-embrane molecularly imprinted polymer membrane prepared by the method described above.

[0017] An application of the electrode described herein, specifically its use in the detection of antibiotics.

[0018] The electrode is used in the detection of the antibiotic vancomycin.

[0019] Furthermore, a synthetic, template-free molecularly imprinted polymer is used as the recognition carrier for a polymer membrane potential sensor. Through a selective recognition process between the recognition carrier and vancomycin, the potential detection of vancomycin is achieved.

[0020] Detection Principle: In recent years, polymer membrane ion-selective electrodes based on molecularly imprinted polymers have been widely developed and utilized for the detection of organic ions or neutral organic compounds. Currently used molecularly imprinted polymers are synthesized in a porogenous solvent in the presence of functional monomers, template molecules, and crosslinking agents. After the free radical polymerization reaction, the polymer is typically washed multiple times in an eluent (such as methanol / acetic acid) for several hours each time to remove the template molecules. Traditional molecularly imprinted polymer membrane potential sensors based on Nernst response usually require treatment of the template ion solution before measurement. Template molecules can diffuse from the aqueous phase to the membrane phase, and the molecularly imprinted polymer in the sensitive membrane recombines with the template molecules. Simultaneously, the counterions of the lipophilic ion exchanger in the membrane phase exchange with the host ions. This invention omits the traditional template removal process during the synthesis of the molecularly imprinted polymer. The polymer is incorporated into the electrode membrane, and during activation, the template molecules are absorbed by the H+ ions in the solution. + Protonation transforms the membrane into an ionic state. To maintain the electroneutrality of the ISE membrane, counterions in the ion exchanger are also released from the membrane into the solution. This leads to the first fabrication of a wash-free molecularly imprinted polymer membrane potentiometric sensor. In this case, the proposed template-free electrode functions identically to conventional MIP-based electrodes. Therefore, the aforementioned cumbersome and time-consuming template removal process is unnecessary, as a significant portion (approximately 85%) of the imprinted cavity cannot be reoccupied by the template and may even reduce electrode repeatability and the recognition efficiency of the molecularly imprinted polymer.

[0021] The advantages of this invention are:

[0022] 1. The present invention synthesizes molecularly imprinted polymers without the complicated and time-consuming process of removing template molecules. This method provides a novel, simple and efficient approach for the development of polymer membrane potential sensors based on molecularly imprinted polymers.

[0023] 2. This invention establishes a template-free synthesis method that can reduce batch-to-batch inconsistencies in molecularly imprinted polymers, thereby improving the repeatability of the established molecularly imprinted polymer membrane potential sensor. This advantage of reproducible production of molecularly imprinted polymers offers the potential to replace other biorecognition carriers such as aptamers.

[0024] 3. The molecularly imprinted polymer potentiometric sensor with no template removal obtained in this invention has good sensitivity and selectivity for vancomycin. It is foreseeable that this new method can lay the foundation for the simple fabrication of various polymer membrane electrochemical sensors, such as potentiometric and capacitive sensors, and ion-sensitive field-effect transistors (ISFETs), for sensitive and selective detection of a variety of target substances. Attached Figure Description

[0025] Figure 1 This is a synthetic route diagram for the wash-free molecularly imprinted polymer provided in the embodiments of the present invention.

[0026] Figure 2 The absorption spectra of MIP in (a) water and (b) tetrahydrofuran are shown. The absorption peak of vancomycin is at 280 nm. Using 10 -4 M vancomycin solution was used as a standard control to estimate its release in the solvent.

[0027] Figure 3 The image shows a traditional MIP (Membrane Injection) SEM image, showing the removal of the template-synthesized MIP by (a) stirred filtration elution and (b) Soxhlet extraction.

[0028] Figure 4 BET plot of MIPs after template removal via (A) stirred filtration elution and (B) Soxhlet extraction.

[0029] Figure 5 Calibration curves for vancomycin anion potential response were obtained for wash-free molecularly imprinted polymer (A) and classical molecularly imprinted polymer (B).

[0030] Figure 6 Real-time potential response and calibration curves for vancomycin anion detection using wash-free molecularly imprinted polymer (A), non-imprinted polymer NIP (B), and blank bare membrane electrodes.

[0031] Figure 7 To measure the sensor's potential response to vancomycin in the presence of different interfering ions. (A) NaOH with pH = 11.5, (B) 10 -3 M Cl - (C)10 -3 M SO4 2- (D)10 -3 M CO3 2- (E)10-3 M HCO3 - (F)10 -3 M PO4 3- (G)10 - 5 M sulfamethoxazole, (H)10 -5 M sulfadiazine, (I)10 -5 Ciprofloxacin (M), (J)10 -5 M ofloxacin, (K)10 -5 M Norfloxacin, (L)10 -5 M sulfadiazine, (M)10 -5 M tetracycline. Detailed Implementation

[0032] The following examples further illustrate specific embodiments of the present invention. It should be noted that the specific embodiments described herein are merely for illustration and explanation and are not intended to limit the scope of the present invention.

[0033] This invention omits the traditional template removal process during the synthesis of molecularly imprinted polymers. This not only simplifies the fabrication process of molecularly imprinted polymer-based potential sensors but also improves the recognition efficiency of recognition carriers. Using vancomycin as a template molecule, this invention aims to create, for the first time, a wash-free molecularly imprinted polymer membrane potential sensor with excellent sensing performance.

[0034] Example 1

[0035] (1) The specific preparation steps of the vancomycin-free, molecularly imprinted polymer membrane ion-selective electrode are as follows:

[0036] a. Preparation of vancomycin-imprinted polymers without washing: such as Figure 1 As shown, the vancomycin molecularly imprinted polymer was synthesized using precipitation polymerization. 0.5 mmol vancomycin and 1 mmol acrylamide were dissolved in 25 mL acetonitrile and allowed to stand for 1 h. Then, 5 mmol of crosslinking agent EGDMA and 25 mg of initiator AIBN were added to the solution, and nitrogen gas was purged for 15 minutes. The glass vial was then sealed under a nitrogen atmosphere. Polymerization was then carried out at 60°C for 18 hours. After polymerization, the resulting block polymer was washed with acetonitrile to remove unreacted compounds, then dried in a vacuum oven at 60°C for 24 h, and finally ground in a mortar and pestle for later use.

[0037] To verify that the template molecule was not removed from the synthesized MIP, a vancomycin release assay was performed on the MIP. Figure 2As shown, when the wash-free MIP microspheres are dispersed in solvents (water and tetrahydrofuran), the template molecules added during the prepolymerization process can be released into the test solvents. The estimated release amounts, based on absorbance at 280 nm, are approximately 10 in tetrahydrofuran and water, respectively. -7 and 10 -8 The difference in template release (mol / mg) may be attributed to the higher binding affinity of the proposed MIP material to the template in water than in THF. This leads to the conclusion that template vancomycin can be released from the MIP receptor into the MIP-sensitive membrane, confirming the feasibility of fabricating a classic Nernst-responsive MIP potential sensor without the need for conventional template removal steps.

[0038] b. Preparation of ordered mesoporous carbon ion-electron conduction layer: Weigh 10 mg of ordered mesoporous carbon material (SSA ≈ 600 m 2 / g was dispersed in 1mL of deionized water and sonicated for 1 hour. 10μL of the ordered mesoporous carbon dispersion was dropped onto the surface of a glassy carbon electrode and dried under an infrared lamp for later use.

[0039] c. Preparation of polymer-sensitive membrane: Weigh 6 wt% of the above-prepared vancomycin-free molecularly imprinted polymer, 2 wt% tris(dodecyl)ammonium chloride (TDMACl), 5 wt% tetra(4-chlorophenyl)borate tetra(dodecyl)ammonium salt (ETH500), 29 wt% polyvinyl chloride (PVC), and 58 wt% di-n-octyl phthalate (DOP), totaling 360 mg, and dissolve them in 3.6 mL of THF. Stir for 4 hours for later use.

[0040] d. Electrode preparation: Take 80 μL of the prepared membrane solution and drop it onto the surface of the glassy carbon electrode modified with the ion-electron conduction layer. Allow it to evaporate naturally at room temperature and dry to obtain a vancomycin-free, molecularly imprinted polymer membrane ion-selective electrode.

[0041] (2) The specific preparation steps of the classic vancomycin molecularly imprinted polymer membrane ion-selective electrode are as follows:

[0042] a. Preparation of vancomycin-free molecularly imprinted polymer: The vancomycin-free molecularly imprinted polymer was synthesized by precipitation polymerization. 0.5 mmol vancomycin, 1 mmol acrylamide, 5 mmol EGDMA, and 25 mg AIBN were dissolved in 25 mL acetonitrile. Nitrogen gas was purged for 10 minutes, and then polymerization was carried out at 60°C for 18 hours. After polymerization, the resulting white particles were washed six times with a methanol / acetic acid (8:2, v / v) solution, followed by multiple washes with pure methanol solution until no vancomycin absorption peak was detected at λ = 280 nm using a UV spectrophotometer. The particles were then dried in a vacuum drying oven at 60°C for later use. After centrifugation, the particles were dried in a vacuum drying oven at 40°C for 24 hours, ground in a mortar, and then ready for use.

[0043] At the same time, in the literature [1,2] The microstructure and specific surface area of ​​the MIPs obtained using existing elution methods capable of effectively eluting template molecules were tested. Two different template extraction methods were employed: classic Soxhlet extraction and stirred filtration extraction, both of which removed template molecules. The two types of MIP microspheres were characterized using scanning electron microscopy, and the results are as follows: Figure 3 As shown, after removing the template agent, the surface morphology of the polymer differs from that of the original microspheres in terms of roughness and particle size. This difference can be attributed to the potential alteration of the polymer's surface morphology during template elution. Therefore, different extraction methods were employed to obtain MIPs with different surface morphologies. Furthermore, the specific surface area of ​​the two molecularly imprinted polymers was characterized using the BET (Brunauer Emmett Teller) method, as shown... Figure 4 As shown. Using nitrogen as the adsorbent, according to the adsorption isotherm, the specific surface area of ​​the molecular sieves obtained by Soxhlet extraction and stirred filtration extraction also differs significantly (11.70 m²). 2 / g ratio 7.07m 2 / g). This is likely because the template removal step in classic MIP preparation can reduce the reproducibility of the synthesis, especially for different operators and different template removal methods, which will further lead to poor reproducibility of the resulting MIP sensor. These results demonstrate that the proposed wash-free MIP has great potential to achieve reproducible production of MIP receptors, just like other biological receptors, such as aptamers.

[0044] b. Preparation of the ordered mesoporous carbon ion-electron conduction layer: Weigh 10 mg of ordered mesoporous carbon material and disperse it in 1 mL of deionized water, then sonicate for 1 hour. Measure 10 μL of the ordered mesoporous carbon dispersion and drop it onto the surface of a glassy carbon electrode, then dry it under an infrared lamp for later use.

[0045] c. Preparation of polymer-sensitive membrane: Weigh 6 wt% vancomycin-imprinted polymer, 2 wt% tris(dodecyl)ammonium chloride (TDMACl), 5 wt% tetra(4-chlorophenyl)borate tetra(dodecyl)ammonium salt (ETH500), 29 wt% polyvinyl chloride (PVC), and 58 wt% di-n-octyl phthalate (DOP), totaling 360 mg, and dissolve them in 3.6 mL THF. Stir for 4 hours before use.

[0046] d. Electrode preparation: Take 80 μL of the prepared membrane solution and drop it onto the surface of the glassy carbon electrode modified with the ion-electron conduction layer. Allow it to evaporate naturally at room temperature and dry to obtain a vancomycin-free, molecularly imprinted polymer membrane ion-selective electrode.

[0047] (3) Electrode response performance test

[0048] a. Working curve test: Two different electrodes prepared in steps (1) and (2) will be tested at 10°C. -5 The prepared ion-selective electrode was activated for 12 hours in a vancomycin solution (pH = 12) and then used as the working electrode. Using an Ag / AgCl electrode as the reference electrode, the electrode was inserted into a series of vancomycin anion solutions of different concentrations to generate potential signals. Simultaneously, an electrode constructed with a blank membrane (containing only TDMACl) was used as a blank control (see [link to documentation]). Figure 5 The electrode enables sensitive detection of vancomycin, with a detection limit as low as 2.5 × 10⁻⁶. -8 M. The response behavior of this wash-free molecularly imprinted polymer electrode is similar to that of conventional electrodes based on molecularly imprinted polymer acceptors, fully demonstrating that molecularly imprinted polymers without template removal are an effective method for fabricating classic polymer membrane potential sensors.

[0049] The potential response curves of wash-free molecularly imprinted polymer membranes, non-imprinted polymer membranes, and blank membranes (containing only TDMACl) are shown below. Figure 6 As shown, the molecularly imprinted polymer film electrode exhibits a better Nernst slope and a wider response range, which confirms the effectiveness of molecularly imprinted polymers as recognition carriers.

[0050] b. Selectivity test: The potential response of each activated electrode to vancomycin anion was measured in the presence of a certain concentration of interfering substance.

[0051] Specifically, when testing the potential response of the activated electrode, 10 μL of [unspecified substance] was added to the background solution beforehand. -3 Inorganic anions, 10 -5 Deprotonated antibiotic ions, the sensor was used to measure vancomycin anion concentrations from 0 to 10. -5 The difference in potential change.

[0052] from Figure 7 As can be seen, the electrode's response to vancomycin anions in pure background solution did not differ significantly from its response in the presence of different interfering ions. These results indicate that the sensor exhibits good selectivity for vancomycin, which may be due to the strong hydrogen bonding between the molecularly imprinted polymer and vancomycin, as well as the three-dimensional (3D) shape matching between the imprinted cavity and the template molecule. This provides great potential for trace potentiometric detection of vancomycin in samples from complex environments.

[0053] c. Repeatability Test: To test the repeatability between different batches, three batches of conventional MIP and wash-free MIP were synthesized for electrode preparation. The potential difference between the electrode blank and the vancomycin test solution at different concentrations was measured, and the standard deviation of the electrode potential difference for the three different preparation batches was calculated, as shown in Table 1.

[0054] Table 1 Standard deviations between electrodes prepared from different batches of classical MIP and wash-free MIP.

[0055]

[0056] Because it omits the template removal process in the traditional MIP synthesis process, it has good reproducibility in MIP synthesis, thereby reducing the difference in recognition ability from different batches of MIPs.

[0057] Example 2

[0058] Except for replacing the functional monomer with methacrylic acid, all other steps are the same as steps (1) to (3) in Example 1.

[0059] Example 3

[0060] Except for replacing the functional monomer acrylamide with methyl methacrylate, all other steps are the same as steps (1) to (3) in Example 1.

[0061] Example 4

[0062] Except for replacing the functional monomer with acrylic acid instead of acrylamide, all other steps are the same as steps (1) to (3) in Example 1.

[0063] References

[0064] [1]Liang RN, Zhang RM, Qin W. Potentiometric sensor based on molecularly imprinted polymer for determination of melamine inmilk. Sens. Actuators B, 2009, 141 (2): 544-550.

[0065] [2]Liang R N,Song D A,Zhang R M,et al.Potentiometric Sensing ofNeutral Species Basedon a Uniform-Sized Molecularly Imprinted Polymer as aReceptor.Angew.Chem.,Int.Ed.,2010,49(14):2556-2559.

Claims

1. A method for constructing a wash-free molecularly imprinted polymer membrane ion-selective electrode for detecting the antibiotic vancomycin, characterized in that: A template-free molecularly imprinted polymer is incorporated into a polymer-sensitive membrane dispersion as a recognition carrier, and then dropped onto the electrode surface modified with an ion-electron conduction layer to obtain a template-free molecularly imprinted polymer membrane ion-selective electrode; wherein the template-free molecularly imprinted polymer accounts for 4-8 wt% of the weight of the polymer-sensitive membrane in the dispersion. The template-free molecularly imprinted polymer membrane ion-selective electrode was activated in vancomycin solution at pH 12 for 12 h and then used as the working electrode. The molecularly imprinted polymer for the wash-free template removal is a mixture of template molecules, functional monomers and crosslinking agents, wherein the template molecule is vancomycin; The polymer-sensitive membrane includes tris(dodecylammonium chloride) TDMACl.

2. A method for the construction of a non-washable molecularly imprinted polymer membrane ion selective electrode for the detection of antibiotic vancomycin as claimed in claim 1, wherein: The wash-free template-removing molecularly imprinted polymer is produced by heating template molecules in the presence of functional monomers, crosslinking agents, initiators, and solvents to induce a polymerization reaction, followed by drying the template molecules for later use; wherein the template molecules, functional monomers, and crosslinking agents are mixed in a molar ratio of 1:1-4:10-20.

3. A method for the construction of a non-washable molecularly imprinted polymer membrane ion selective electrode for the detection of the antibiotic vancomycin according to claim 1 or 2, characterized in that: The template-free molecularly imprinted polymer is obtained by mixing template molecules, functional monomers, and crosslinking agents, adding the mixture to a reaction solvent, mixing thoroughly, letting it stand for 30-60 minutes, purging with nitrogen for 10-30 minutes, quickly adding 25-50 mg of initiator, and thermally initiating polymerization at 60-80 degrees Celsius for 12-24 hours under sealed conditions to obtain a block polymer; then drying it in a vacuum drying oven.

4. The method for the construction of a non-washable molecularly imprinted polymer membrane ion selective electrode for the detection of antibiotic vancomycin as claimed in claim 3, wherein: The crosslinking agent is one or more of ethylene glycol dimethacrylate (EGDMA), trimethylolpropane trimethacrylate (TRIM), and divinylbenzene (DVB); the initiator is azobisisobutyronitrile (AIBN) or azobisisoheptanenitrile (ADVN); and the reaction solvent is acetonitrile, acetone, dichloromethane, trichloromethane, or tetrahydrofuran.

5. The method for the construction of a non-washable molecularly imprinted polymer membrane ion selective electrode for the detection of antibiotic vancomycin as claimed in claim 3, wherein: The functional monomer is acrylamide, methacrylic acid, or methyl methacrylate.

6. The method for the construction of a non-washable molecularly imprinted polymer membrane ion selective electrode for the detection of antibiotic vancomycin as claimed in claim 1, wherein: The polymer-sensitive membrane dispersion is composed of a polymer-sensitive membrane and a solvent, wherein the weight-to-volume ratio of the two is 80-100; wherein the polymer-sensitive membrane is, by mass percentage, 4-8 wt% of a molecularly imprinted polymer (MIP) that does not require washing to remove templates, 0.5-2 wt% of tris(2-dodecyl)ammonium chloride (TDMACl), 1-5 wt% of tetra(4-chlorophenyl)borate tetra(dodecyl)ammonium salt (ETH500), 28.3-31.5 wt% of polyvinyl chloride (PVC), and 57-63 wt% of di(n-octyl) phthalate (DOP); The solvent is tetrahydrofuran (THF); The ion-electron conductive layer is formed by dispersing an ion-electron conductive material in deionized water to form a dispersion with a final concentration of 5-10 mg / mL, and then dropping the dispersion onto the surface of the electrode substrate to form the ion-electron conductive layer; wherein, the ion-electron conductive material is ordered mesoporous carbon, carbon nanotubes, nanoporous gold, polypyrrole, poly3-octylthiophene, or poly3,4-ethylenedioxythiophene.

7. An ion-selective electrode characterized by: The ion-selective electrode is prepared by the method described in claim 1.

8. Use of an ion-selective electrode according to claim 7, characterized in that: Application of the ion-selective electrode in the detection of antibiotics.

9. Use of an ion-selective electrode according to claim 8, characterised in that: Application of the ion-selective electrode in the detection of the antibiotic vancomycin.

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