CN104034790B - Perfluorinated sulfonic acid resin modified SnO 2-coated ZnO nanotube array electrode for detecting dopamine and application - Google Patents

Abstract

The invention belongs to the technical field of nano material application, and particularly relates to perfluorinated sulfonic acid resin (Nafion) modified SnO for detecting dopamine₂A ZnO coated nanotube array electrode and application. The nanotube array electrode is a polycrystalline SnO (stannic oxide) modified by a conductive substrate and Nafion vertically grown on the conductive substrate₂The nano-particle film is coated with the array of the single crystal ZnO nano-tube. The Nafion modified SnO for detecting dopamine₂The ZnO-coated nanotube array electrode can detect dopamine in an aqueous solution, and can generate a very strong electrochemical signal when the dopamine in the aqueous solution is detected by Cyclic Voltammetry (CV) or Differential Pulse Voltammetry (DPV) by taking the nanotube array electrode as a working electrode, a platinum sheet electrode as a counter electrode and a saturated calomel electrode as a reference electrode.

Description

Perfluorosulfonic acid resin modified SnO2 coated ZnO nanotube array electrode for detecting dopamine and its application

technical field

The invention belongs to the technical field of nanomaterial application, and in particular relates to a perfluorosulfonic acid resin (Nafion) modified SnO ₂ coated ZnO nanotube array electrode for detecting dopamine and its application.

Background technique

Dopamine (DA) is an important neurotransmitter that plays an important role in the central nervous system, hormone system, cardiovascular system and kidney function. The concentration of DA in the human body will change with some major diseases, such as schizophrenia, Parkinson's disease, Alzheimer's disease, AIDS infection and so on. Therefore, the detection of DA concentration in the human body is of great significance for neurophysiological research, disease diagnosis and control of related drugs.

Electrochemical sensors are an important means of dopamine detection. In electrochemical sensors, the most important building blocks are electrodes that respond to dopamine. Due to the extremely low concentration of dopamine in organisms and the strong interference from ascorbic acid in the detection process of dopamine, it is necessary to develop electrochemical sensor electrodes with high sensitivity and high selectivity for dopamine. The development of nanotechnology provides a good opportunity for improving the performance of dopamine electrochemical sensors. Due to their large specific surface area and special physical/chemical properties, nanomaterials have been used in the construction of dopamine electrochemical sensor electrodes. Among them, one-dimensional nanomaterials such as nanorods, nanowires, nanobelts, and nanotubes are particularly attractive. This is because these one-dimensional nanomaterials not only have a huge specific surface area, but their special one-dimensional structure can also serve as a "fast channel" for charge transport, quickly transporting electrons participating in electrochemical reactions to the external circuit, thereby improving sensor performance. performance. At present, as the most typical one-dimensional nanomaterials, carbon nanotubes have been widely used in dopamine electrochemical sensor electrodes (Electroanalysis, 2005, 17, 417; Analyst, 2007, 132, 876; Sensors, 2009, 9, 376; Biosensors and Bioelectronics, 2011, 26, 2917 ; Sensors and Actuators B: Chemical, 2012, 171, 1132; Electrochimica Acta, 2013, 91, 261; Chinese Journal of Catalysis, 2014, 35, 201.). However, in these electrodes, carbon nanotubes are usually distributed on the electrode surface in a disorderly manner, and their role as a "fast channel" for charge transport has not been fully utilized.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a dopamine electrochemical sensor electrode for detecting dopamine based on perfluorosulfonic acid resin (Nafion) modified SnO ₂ coating ZnO nanotube arrays.

Still another object of the present invention is to provide the application of the dopamine electrochemical sensor electrode based on perfluorosulfonic acid resin (Nafion) modified SnO ₂ coated ZnO nanotube arrays for detecting dopamine.

The perfluorosulfonic acid resin (Nafion) modified _SnO2 coated ZnO (SnO2ZnO ₎ nanotube array electrode for detecting dopamine of the present invention is composed of a conductive substrate and a perfluorosulfonic acid grown vertically on the conductive substrate. Acid resin (Nafion) modified polycrystalline SnO ₂ nanoparticle film coated single crystal ZnO nanotube arrays.

The conductive substrate can be ITO glass or FTO glass.

The polycrystalline SnO ₂ nanoparticle film coating the single crystal ZnO nanotube is that the film formed by the polycrystalline SnO ₂ nanoparticle evenly covers the inner wall and the outer wall of the single crystal ZnO nanotube.

The modification of the perfluorosulfonic acid resin (Nafion) is by soaking the array of polycrystalline _SnO nanoparticle film-coated single crystal ZnO nanotubes in a Nafion solution with a mass concentration of 5% (the time of generally soaking is 8 ~15 minutes) to achieve.

The perfluorosulfonic acid resin (Nafion) used to detect dopamine of the present invention modifies SnO ₂ The preparation method of the nanotube array electrode coated with ZnO (SnO ₂ ZnO) is as follows: first, use the electrochemical deposition method on the conductive substrate (ITO glass or FTO glass) to prepare ZnO nanorod arrays, and etch the prepared ZnO nanorod arrays in an inorganic alkaline aqueous solution to obtain single crystal ZnO nanotube arrays; then, to grow a conductive substrate with single crystal ZnO nanotube arrays As the substrate, a layer of polycrystalline SnO ₂ nanoparticle film was prepared on the inner and outer surfaces of single crystal ZnO nanotubes by thermal evaporation; the polycrystalline SnO ₂ nanoparticle film was coated on the array of single crystal ZnO nanotubes at a mass concentration of 5 % Nafion solution for soaking (general soaking time is 8-15 minutes).

Perfluorosulfonic acid resin (Nafion) modified SnO ₂ coated ZnO (SnO ₂ ZnO) nanotube array electrode for detecting dopamine of the present invention can detect dopamine in aqueous solution, use nanotube array electrode of the present invention as Working electrode, with platinum sheet electrode as counter electrode, with saturated calomel electrode as reference electrode, when using cyclic voltammetry (CV) or differential pulse voltammetry (DPV) to detect dopamine in aqueous solution, the present invention Nanotube array electrodes can generate extremely strong electrochemical signals.

The described cyclic voltammetry (CV) or differential pulse voltammetry (DPV) detects dopamine in aqueous solution, the linear response range of cyclic voltammetry (CV) is 0.1～500 μ M, differential pulse voltammetry ( DPV) has a linear response range of 0.1-2 μM.

The concentration of dopamine in the aqueous solution is 0.1 μM to 500 μM.

In the dopamine electrochemical sensor electrode of the present invention, Nafion-modified SnO ₂ nanotubes coated with ZnO (SnO ₂ ZnO) are vertically grown on the conductive substrate to form an ordered array, and the electrons that undergo electrochemical reactions can be moved along the The above-mentioned nanotubes are quickly transported to the external circuit, which fully exerts the potential of one-dimensional nanomaterials as an "express channel" for charge transport, and effectively improves the performance of the dopamine electrochemical sensor.

Description of drawings

Fig. 1. The SEM image of the array of single crystal ZnO nanotubes coated with polycrystalline _SnO2 nanoparticle film of Nafion modified in Example 1 of the present invention.

Figure 2. HRTEM (a) and SAED (b) images of a single polycrystalline SnO ₂ nanoparticle film coated single crystal ZnO nanotube prepared in Example 1 of the present invention.

Figure 3. CV(a) and DPV(b) diagrams of Example 2 of the present invention.

Figure 4. CV(a) and DPV(b) diagrams of Example 3 of the present invention.

Figure 5. CV(a) and DPV(b) diagrams of Example 4 of the present invention.

Figure 6. CV(a) and DPV(b) diagrams of Example 5 of the present invention.

Figure 7. CV(a) and DPV(b) diagrams of Example 6 of the present invention.

Figure 8. The CV diagram (a) and CV calibration curve (b) of Example 7 of the present invention, and the DPV diagram (c) and DPV calibration curve (d).

detailed description

Example 1.

In the three-electrode system, a platinum plate and a saturated calomel electrode were used as the counter electrode and a reference electrode, respectively, and ITO glass or FTO glass was used as the working electrode. The electrolyte solution is an aqueous solution containing 5mM zinc nitrate and 5mM ammonium acetate. The electrolyte temperature was raised to and maintained at 85°C by means of a water bath. Using an electrochemical workstation (CHI660C, Shanghai Chenhua Instrument Co., Ltd.) to apply a potential of -1V to the working electrode for 3 hours, the ZnO nanorod array grown on ITO glass or FTO glass was obtained; this ZnO nanorod array was placed on The single crystal ZnO nanotube array is obtained by immersing for 1.5 hours in an aqueous solution of sodium hydroxide with a concentration of 0.2M and a temperature of 85°C. Place the ITO glass or FTO glass with the single crystal ZnO nanotube array in the porcelain boat, put it in the low-temperature central area of the dual-temperature zone tube furnace, and place the glass containing 2 grams of SnO powder in the high-temperature central area of the tube furnace. porcelain boat. The system was evacuated with a mechanical pump, and Ar/H ₂ mixed gas (wherein the volume content of H ₂ was 5%) was introduced into the system, and the flow rate was 50 sccm. Heat the tube furnace with a heating rate of 20°C/min, so that the temperatures of the high temperature center and the low temperature center reach 850°C and 600°C respectively, and after maintaining this temperature for 1 hour, stop heating; when the temperature drops to room temperature, take out the sample, that is An array of single crystal ZnO nanotubes coated with polycrystalline SnO ₂ nanoparticle films was obtained, and the film formed by polycrystalline SnO ₂ nanoparticles uniformly coated the inner and outer walls of single crystal ZnO nanotubes. Soak the polycrystalline _SnO nanoparticle film-coated array of single crystal ZnO nanotubes in a Nafion solution with a mass concentration of 5% for 10 minutes, take it out, and let it dry naturally, so that it can grow vertically on ITO glass or FTO glass. Arrays of single-crystalline ZnO nanotubes coated with Nafion-modified polycrystalline _SnO2 nanoparticle films. The morphology of the prepared Nafion-modified polycrystalline SnO ₂ nanoparticle film-coated single-crystal ZnO nanotube array and the structural characterization of a single polycrystalline SnO ₂ nanoparticle film-coated single-crystal ZnO nanotube are shown in Figure 1 and Figure 2 shows. This Nafion-modified polycrystalline _SnO2 nanoparticle film-coated array of single-crystalline ZnO nanotubes can be used to detect dopamine in aqueous solution.

Example 2.

The polycrystalline _SnO modified by Nafion grown vertically on the ITO glass substrate obtained in Example 1 The array of nanoparticle film-coated single-crystal ZnO nanotubes is the working electrode, the platinum sheet electrode is used as the counter electrode, and the saturated calomel The electrode is used as a reference electrode to form a three-electrode electrochemical system. The detection object is a PBS solution (pH=7.4) containing 0.1 μM dopamine. Through the electrochemical workstation, the electrochemical response of the detection object was tested by cyclic voltammetry (CV) and differential pulse voltmetry (DPV), and the results are shown in FIG. 3 .

Example 3.

The polycrystalline _SnO modified by Nafion grown vertically on the ITO glass substrate obtained in Example 1 The array of nanoparticle film-coated single-crystal ZnO nanotubes is the working electrode, the platinum sheet electrode is used as the counter electrode, and the saturated calomel The electrode is used as a reference electrode to form a three-electrode electrochemical system. The detection object is a PBS solution (pH=7.4) containing 2 μM dopamine. Through the electrochemical workstation, the electrochemical response of the detection object was tested by cyclic voltammetry (CV) and differential pulse voltmetry (DPV), and the results are shown in FIG. 4 .

Example 4.

The polycrystalline _SnO modified by Nafion grown vertically on the ITO glass substrate obtained in Example 1 The array of nanoparticle film-coated single-crystal ZnO nanotubes is the working electrode, the platinum sheet electrode is used as the counter electrode, and the saturated calomel The electrode is used as a reference electrode to form a three-electrode electrochemical system. The detection object is a PBS solution (pH=7.4) containing 10 μM dopamine. Through the electrochemical workstation, the electrochemical response of the detection object was tested by cyclic voltammetry (CV) and differential pulse voltmetry (DPV), and the results are shown in FIG. 5 .

Example 5.

The polycrystalline _SnO modified by Nafion grown vertically on the FTO glass substrate obtained in Example 1 The array of nanoparticle film-coated single-crystal ZnO nanotubes is the working electrode, the platinum plate electrode is used as the counter electrode, and the saturated calomel The electrode is used as a reference electrode to form a three-electrode electrochemical system. The detection object is a PBS solution (pH=7.4) containing dopamine at a concentration of 100 μM. Through the electrochemical workstation, the electrochemical response of the detection object was tested by cyclic voltammetry (CV) and differential pulse voltmetry (DPV), and the results are shown in FIG. 6 .

Example 6.

The polycrystalline _SnO modified by Nafion grown vertically on the ITO glass substrate obtained in Example 1 The array of nanoparticle film-coated single-crystal ZnO nanotubes is the working electrode, the platinum sheet electrode is used as the counter electrode, and the saturated calomel The electrode is used as a reference electrode to form a three-electrode electrochemical system. The detection object is a PBS solution (pH=7.4) containing 500 μM dopamine. Through the electrochemical workstation, the electrochemical response of the detection object was tested by cyclic voltammetry (CV) and differential pulse voltmetry (DPV), and the results are shown in FIG. 7 .

Example 7.

The polycrystalline _SnO modified by Nafion grown vertically on the ITO glass substrate obtained in Example 1 The array of nanoparticle film-coated single-crystal ZnO nanotubes is the working electrode, the platinum sheet electrode is used as the counter electrode, and the saturated calomel The electrode is used as a reference electrode to form a three-electrode electrochemical system. The detection object is a PBS solution (pH=7.4) containing dopamine at a concentration of 0.1-500 μM. Through the electrochemical workstation, the electrochemical response of the detection object was tested by cyclic voltammetry (CV) and differential pulse voltmetry (DPV), and the results are shown in FIG. 8 .

Claims (6)

1. modify SnO for the perfluorinated sulfonic resin detecting dopamine for one kind ₂the nanometer pipe array electrode of clading ZnO, is characterized in that: described nanometer pipe array electrode is the polycrystalline SnO by conductive substrates and the vertically perfluorinated sulfonic resin modification of growth in this conductive substrates ₂the array of the coated single crystal ZnO nanotube of nano-particular film is formed.

2. the perfluorinated sulfonic resin for detecting dopamine according to claim 1 modifies SnO ₂the nanometer pipe array electrode of clading ZnO, is characterized in that: described conductive substrates is ito glass or FTO glass.

3. the perfluorinated sulfonic resin for detecting dopamine according to claim 1 modifies SnO ₂the nanometer pipe array electrode of clading ZnO, is characterized in that: described polycrystalline SnO ₂the coated single crystal ZnO nanotube of nano-particular film is by polycrystalline SnO ₂the film that nano particle is formed evenly is coated on the inner and outer wall of single crystal ZnO nanotube.

4. the perfluorinated sulfonic resin for detecting dopamine according to claim 1 modifies SnO ₂the nanometer pipe array electrode of clading ZnO, is characterized in that: it is by by polycrystalline SnO that described perfluorinated sulfonic resin is modified ₂the array of the coated single crystal ZnO nanotube of nano-particular film is carry out soaking realizing in the perfluor sulfoacid resin solution of 5% in mass concentration.

5. the perfluorinated sulfonic resin modification SnO for detecting dopamine described in a Claims 1 to 4 any one ₂the application of the nanometer pipe array electrode of clading ZnO, it is characterized in that: described nanometer pipe array electrode is used for detecting the dopamine in aqueous solution, using described nanometer pipe array electrode as working electrode, using platinum plate electrode as to electrode, using saturated calomel electrode as contrast electrode, when detecting the dopamine in aqueous solution with cyclic voltammetry or differential pulse voltammetry, described nanometer pipe array electrode produces extremely strong electrochemical signals;

The linear response range of cyclic voltammetry is 0.1 ~ 500 μM, and the linear response range of differential pulse voltammetry is 0.1 ~ 2 μM.

6. application according to claim 5, is characterized in that: the concentration of the dopamine in described aqueous solution is 0.1 μM to 500 μMs.