A method for preparing an electrochemical sensor immobilization layer material

Abstract

The application relates to the technical field of potential type chemical sensors, and discloses a preparation method of an electrochemical sensor fixed layer material, which comprises the following steps: Ti3C2 MXene etched is dissolved in NMP to prepare a Ti3C2 MXene solution; the Ti3C2 MXene solution is dropped on the surface of a glassy carbon electrode for 3-5 times, the electrode is dried, and the electrode covered with Ti3C2 MXene is obtained; polyaniline is electropolymerized on the surface of the electrode covered with Ti3C2 MXene, and then washing is carried out; after the electropolymerization, polyaniline with coral-shaped protrusions is formed on the surface of the Ti3C2 MXene, and the polyaniline@Ti3C2 MXene is used as a high-efficiency ion-electron transmission fixed layer material and is used for selective detection of an ion selective electrode. The application has high ion-electron transmission efficiency, and can improve the stability and durability of detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of potential type chemical sensor, and particularly relates to a preparation method of a solid contact layer material of an electrochemical sensor. BACKGROUND

[0002] Potential type chemical sensors have been widely concerned due to their miniaturization, simple structure, convenience of use, high selectivity and high sensitivity to target ions. As an important branch of potential type chemical sensors, solid-state ion selective electrodes have many advantages compared with traditional liquid junction ion selective electrodes, such as long-term use without maintenance, adaptation to extreme environments such as high pressure (ocean floor) and low temperature (extremely low), miniaturization, flexible preparation, low cost, simple preservation, long-term stability and the like. Solid-state ion selective electrodes have been applied to many fields, such as environmental monitoring, water quality analysis, ocean exploration, agriculture, food and drug analysis and the like.

[0003] In solid-state ion selective electrodes, the solid contact conductive layer plays a key role in the sensitivity, stability and accuracy of electrode response. The solid contact conductive layer material should have mixed electrochemical redox ability and ion self-exchange ability.

[0004] At present, a large number of solid contact conductive layer materials are used in the design of solid-state ion selective electrodes, such as carbon-based materials (such as graphene, carbon nanotubes) and conductive polymers (poly pyrrole and poly 3-octyl thiophene) and composites of noble metal nano-ions and graphene and composites of noble metal nanoparticles and carbon nanotubes. Although the solid-state ion selective electrode with an ion-sensitive film should theoretically have high and reversible ion-electron conversion, the real miniaturized preparation technology is still a challenge. Developing high-quality solid contact conductive layer materials to realize stable and rapid ion-electron transmission and improve the measurement accuracy and service life is the development trend of the current solid-state ion sensor.

[0005] Compared with the Ti3C2 MXene prepared in the experiment which has a two-dimensional layered structure, the existing solid contact conductive layer materials such as carbon-based materials and charged polymers have smaller capacitance and greatly reduced electron-ion transmission efficiency. The composites of noble metal nanoparticles are expensive and cannot be widely used in production and life. In addition, the above solid contact conductive layer materials have communication obstacles on the interface with the ion selective sensitive film. The essence is that the ion selective sensitive film and the solid contact conductive layer are not closely attached, but a water layer is generated between them, which isolates the contact between them. Due to the existence of the water layer, the test signal drifts during the open circuit test, and the test result cannot reflect the true information of the ion concentration in the bulk solution. Moreover, the smooth contact surface of the flat solid contact layer material and the sensitive film is easy to cause the sensitive film to fall off, greatly reducing the service life of the sensitive film.

[0006] Therefore, this invention proposes a method for preparing an electrochemical sensor bonding layer material. Summary of the Invention

[0007] (a) Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this invention provides a method for preparing an electrochemical sensor bonding layer material, thereby solving the aforementioned problems.

[0009] (II) Technical Solution

[0010] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0011] A method for preparing an electrochemical sensor bonding layer material includes the following steps:

[0012] Step 1: Dissolve the etched Ti3C2MXene in NMP to prepare a Ti3C2MXene solution;

[0013] Step 2: Take the prepared Ti3C2MXene solution and drop it onto the surface of the glassy carbon electrode, 2-50 μL each time, for a total of 3-5 times. After the electrode dries, it is ready for use, and an electrode covered with Ti3C2MXene is obtained.

[0014] Step 3: Electropolymerize polyaniline on the electrode surface covered with Ti3C2MXene, followed by cleaning;

[0015] Step 4: After electropolymerization, a polyaniline with coral-like protrusions is formed on the surface of Ti3C2MXene, which serves as a highly efficient ion-electron transport bonding layer material. PANI@Ti3C2MXene is used for selective detection by ion-selective electrodes.

[0016] Preferably, the Ti3C2MXene in the first step is 10-20 mg, and the concentration of the Ti3C2MXene solution is 10-20 mg / mL.

[0017] Preferably, the Ti3C2MXene solution in the second step is added dropwise in two portions, 10 μL each time, and dried at 30-60 °C for 60 min.

[0018] Preferably, the electropolymerization scanning potential in the third step is 0.2V to 1.2V, the scanning rate is 30 to 50mV / s, and the number of scanning cycles is 10 to 30.

[0019] Preferably, the cleaning conditions in the third step are to wash with deionized water 3-5 times after polymerization.

[0020] Preferably, the electropolymerization of polyaniline in the third step includes the preparation of an acidic aniline solution:

[0021] The acid can be one of sulfuric acid, hydrochloric acid, or phosphoric acid, with a concentration of 0.3–0.8 mol / L. The concentration of the aniline solution is 0.1–0.5 mol / L, where aniline exists as a polymerization monomer and the acid acts as a protonating agent in the polymerization process.

[0022] Preferably, the ion-selective membrane is prepared by comprising: 0.5%–4% ion carrier, 0.1%–0.8% sodium tetraborate, 25%–35% polyvinyl chloride, and 60%–75% sebacic acid diester, totaling 100%.

[0023] Preferably, the process of selective detection by the ion-selective electrode in the fourth step involves adding the ion-selective membrane solution dropwise onto the surface of the bonding layer material in 3 to 5 drops, each drop being 10 to 20 microliters, and then drying it at 50°C for 30 minutes.

[0024] (III) Beneficial Effects

[0025] Compared with the prior art, the method for preparing the electrochemical sensor bonding layer material provided by the present invention has the following advantages:

[0026] Beneficial effects:

[0027] 1. This method for preparing the electrochemical sensor bonding layer material involves electrochemically polymerizing polyaniline on the surface of a two-dimensional Ti3C2MXene material with high capacitance. Compared with traditional bonding layer materials, this method offers high ion-electron transport efficiency, low manufacturing cost, and more effective adhesion to ion-selective sensitive membranes, significantly reducing the impact of water layers and improving the stability and durability of detection.

[0028] 2. The preparation method of the ion-selective electrode bonding layer material provided by the present invention is applicable to various solid-state sensors and can play an important role in environmental monitoring, water quality analysis, marine research, agriculture, food and drug analysis and other fields. Attached Figure Description

[0029] Fig. 1 This is a schematic diagram of the PANI@Ti3C2MXene solid-state contact conductive layer in an embodiment of the present invention;

[0030] Fig. 2 This is a schematic diagram of the sodium ion selective electrode impedance test of an embodiment of the present invention with PANI@Ti3C2MXene as the bonding layer;

[0031] Fig. 3 This is a schematic diagram of the sodium ion selective electrode ion response test of the PANI@Ti3C2MXene as the bonding layer in an embodiment of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example

[0034] Example 1

[0035] Please see Figs. 1-3 The method for preparing the electrochemical sensor bonding layer material provided in this embodiment of the invention includes the following steps:

[0036] Preparation of acidic aniline solution: The acid used in this experiment can be one of sulfuric acid, hydrochloric acid, or phosphoric acid, with a concentration of 0.3–0.8 mol / L and a concentration of aniline solution of 0.1–0.5 mol / L. Aniline exists as a polymerization monomer, and the acid used is a protonating agent in the polymerization reaction process.

[0037] S1: Dissolve 10-20 mg of etched Ti3C2MXene in NMP to prepare a Ti3C2MXene solution with a concentration of 10-20 mg / mL.

[0038] S2: Take the prepared Ti3C2MXene solution and drop it onto the surface of the glassy carbon electrode, 2-50 μL each time, for a total of 3-5 drops. After the electrode dries, it is ready for use.

[0039] S3: Polyaniline was electropolymerized on the electrode surface covered with Ti3C2MXene using cyclic voltammetry. The scanning potential was 0.2V to 1.2V, the scanning rate was 30 to 50mV / s, and the number of scans was 10 to 30.

[0040] S4: After electropolymerization, a polyaniline with coral-like protrusions is formed on the surface of Ti3C2MXene and serves as a highly efficient ion-electron transport bonding layer material. PANI@Ti3C2MXene is used as an ion-selective electrode to directly and selectively detect pH.

[0041] Example 2

[0042] The method for preparing the electrochemical sensor bonding layer material provided in this embodiment of the invention includes the following steps:

[0043] Preparation of acidic aniline solution: The acid used in this experiment can be one of sulfuric acid, hydrochloric acid, or phosphoric acid, with a concentration of 0.3–0.8 mol / L and a concentration of aniline solution of 0.1–0.5 mol / L. Aniline exists as a polymerization monomer, and the acid used is a protonating agent in the polymerization reaction process.

[0044] S1: Dissolve 10-20 mg of etched Ti3C2MXene in NMP to prepare a Ti3C2MXene solution with a concentration of 10-20 mg / mL.

[0045] S2: Add the prepared Ti3C2MXene solution dropwise onto the surface of the glassy carbon electrode in two separate drops of 10 μL each, and dry at 30-60℃ for 60 min.

[0046] S3: Polyaniline was electropolymerized on a glassy carbon electrode surface with Ti3C2MXene added by cyclic voltammetry. The scanning potential was 0.2V to 1.2V, the scanning rate was 30 to 50mV / s, and the number of scans was 10 to 30. After polymerization, the electrode was washed with deionized water 3 to 5 times to remove residual acid from the material surface.

[0047] S4: After electropolymerization, a polyaniline with coral-like protrusions is formed on the surface of Ti3C2MXene, which serves as a highly efficient ion-electron transport bonding layer material. PANI@Ti3C2MXene is used for selective detection by ion-selective electrodes.

[0048] Preparation of ion-selective membrane: The sodium ion-selective membrane is composed of 0.5%-4% ion carrier, 0.1%-0.8% sodium tetraborate, 25%-35% polyvinyl chloride, and 60%-75% bis(2-ethylhexyl) sebacate, with a total content of 100%.

[0049] The ion-selective membrane solution was dropped onto the surface of the bonding layer material in 3 to 5 drops, each drop being 10 to 20 microliters, and then dried at 50°C for 30 minutes.

[0050] Different ion concentrations were detected by coating the surface of the bonding layer material PANI@Ti3C2MXene with films of varying ion selectivity. The detected ions included Na+. + K + Cl - Ca 2+ Ion detection.

[0051] The technical solution of this invention relates to the preparation process of all-solid-state ISE ion-selective electrodes, and prepares a new material for the ion-selective electrode bonding layer with high specific surface area, fast ion electron transport capability, strong surface adhesion capability, easy preparation, low cost, and effective reduction of the influence of water layer between the electrode and the selective ion sensitive membrane.

[0052] The method for preparing the ion-selective electrode bonding layer material provided by this invention is applicable to various solid-state sensors and can play an important role in fields such as environmental monitoring, water quality analysis, marine exploration, agriculture, food and drug analysis.

[0053] All-solid-state ISE ion-selective electrode: An electrode with a sensitive membrane that can selectively respond to ions or molecular substances. Analytical methods using this type of electrode belong to potentiometric analysis in electrochemical analysis, abbreviated as ISE.

[0054] Bonding layer material: A solid contact layer formed between the selectively sensitive film and the conductive substrate, referred to as the bonding layer. This experiment describes a method for preparing an electrochemical sensor bonding layer material by electropolymerizing polyaniline on the surface of Ti3C2MXene. Commonly used ion-selective electrode materials include graphene, carbon nanotubes, conductive carbon black, gold nanoparticles, and silver nanoparticles. Ti3C2MXene, as a novel two-dimensional material, has been extensively studied in supercapacitors, lithium-ion batteries, energy storage materials, and thermal conductive materials; however, its use as an ion-selective electrode material is relatively limited. CN201811379818.3 first proposed an all-solid-state ion-selective electrode based on MXene nanosheet modification and its preparation method, but this system only used etched MXene nanomaterials as the modification material for the all-solid-state ion-selective electrode. In contrast, this study further constructed coral-like polyaniline nanomaterials on Ti3C2MXene, and the synergistic properties of the two materials achieved excellent results in improving the performance of the all-solid-state ion-selective electrode.

[0055] Ti3C2MXene: The chemical formula of MXenes is represented by M n+1 X n T x In this model, M represents a transition metal, X represents C, N, or a combination of both, and Tx represents surface functional groups. MXenes are primarily synthesized by etching the A layer (group IIIA and IVA elements) of the MAX phase. MAX has a layered hexagonal structure, where the A layer and M... n+1 X n By alternating stacking, this experiment used LiF to etch the Al in Ti3AlC2MXene to prepare Ti3C2MXene with a two-dimensional layered structure.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an electrochemical sensor, characterized in that, Includes the following steps: Step 1: Dissolve the etched Ti3C2 MXene in NMP to prepare a Ti3C2 MXene solution; Step 2: Take the prepared Ti3C2 MXene solution and drop it onto the surface of the glassy carbon electrode, 2-50 μL each time, for a total of 3-5 drops. After the electrode dries, it is ready for use, and an electrode covered with Ti3C2 MXene is obtained. Step 3: Electropolymerize polyaniline on the electrode surface covered with Ti3C2 MXene, followed by cleaning; Step 4: After electropolymerization, a polyaniline with coral-like protrusions is formed on the surface of Ti3C2 MXene, which serves as a highly efficient ion-electron transport bonding layer material. PANI@Ti3C2 MXene is used for selective detection by ion-selective electrodes. The electropolymerization scanning potential in the third step is 0.2V to 1.2V, the scanning rate is 30 to 50mV / s, and the number of scans is 10 to 30. The process of selective detection by the ion-selective electrode in the fourth step involves adding the ion-selective membrane solution dropwise onto the surface of the bonding layer material in 3 to 5 drops, each drop being 10 to 20 microliters, and then drying it at 50°C for 30 minutes.

2. The method for preparing the electrochemical sensor according to claim 1, characterized in that: The Ti3C2MXene in the first step is 10-20 mg, and the concentration of the Ti3C2MXene solution is 10-20 mg / mL.

3. The method for preparing the electrochemical sensor according to claim 1, characterized in that: The Ti3C2MXene solution in the second step was added dropwise in two portions, 10 μL each time, and dried at 30-60 °C for 60 min.

4. The method for preparing the electrochemical sensor according to claim 1, characterized in that: The cleaning conditions in the third step are to wash with deionized water 3-5 times after polymerization.

5. The method for preparing the electrochemical sensor according to claim 1, characterized in that: The electropolymerization of polyaniline in the third step includes the preparation of an acidic aniline solution: The acid is one of sulfuric acid, hydrochloric acid, or phosphoric acid, with a concentration of 0.3–0.8 mol / L. The concentration of the aniline solution is 0.1–0.5 mol / L, where aniline exists as a polymerization monomer and the acid acts as a protonating agent in the polymerization process.

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