All-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 as well as preparation method and application of all-solid-state copper ion selective electrode

Abstract

The invention discloses an all-solid-state copper ion selective electrode based on a polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as a solid transfer layer, and a preparation method and application thereof, and belongs to the technical field of ion selective electrodes. The solid-state transfer layer covers the end face of the columnar conductive substrate, the copper ion selective membrane covers the solid-state transfer layer, and the solid-state transfer layer is made of polydimethylsiloxane and amorphous hollow ZnSnO3 composite materials. According to the invention, the polydimethylsiloxane for enhancing the hydrophobicity of the material and the amorphous hollow ZnSnO3 composite material with large specific surface area are combined to obtain the composite material for reducing the interface resistance and the water layer effect. The electrode can be applied to a potentiometric sensor for detecting Cu < 2 + >, has excellent detection limit, sensitivity and long-term stability as well as excellent hydrophobicity and anti-interference capability, and can still keep optimal detection performance under complex conditions.

Description

Technical Field

[0001] This invention belongs to the field of ion-selective electrode technology, specifically relating to an all-solid-state copper ion-selective electrode based on polydimethylsiloxane (PDMS) and amorphous hollow ZnSnO3 (HZTO) composite material as a solid-state transition layer, its preparation method, and its application, particularly in the detection of Cu. 2+ Applications in potentiometric sensors. Background Technology

[0002] Heavy metal ion pollution has become a major challenge in the global environmental and public health fields. Copper ions, as a common pollutant, are widely present in industrial wastewater, agricultural drainage, and natural water bodies. Although copper is an essential trace element for the human body, excessive intake can lead to serious health problems such as liver and kidney damage and nervous system disorders. Therefore, developing efficient, sensitive, and real-time copper ion detection technologies is crucial for environmental protection, water resource management, and food safety. Traditional copper ion detection methods, such as atomic absorption spectrometry, inductively coupled plasma mass spectrometry, and electrochemical analysis, while highly accurate, often rely on expensive instruments, complex sample pretreatment, and demanding laboratory environments, failing to meet the needs of rapid on-site monitoring. Electrochemical analysis methods based on ion-selective electrodes, however, offer advantages such as simple equipment, high sensitivity, and good selectivity, showing broad application prospects in wastewater detection.

[0003] Traditional liquid-contact ion-selective electrodes suffer from problems such as internal filling liquid leakage, mechanical instability, and maintenance difficulties, limiting their widespread application. To overcome these drawbacks, all-solid-state contact ion-selective electrodes have emerged. By introducing a solid-state transition layer to replace the liquid contact, an all-solid-state design is achieved, improving the electrode's stability and durability. Nevertheless, existing all-solid-state contact ion-selective electrodes still face challenges such as high interfacial resistance, severe potential drift, and insufficient detection limits, especially for the detection of low concentrations of copper ions. Therefore, developing a solid-state transition layer material with better specific capacitance, higher conductivity, and better hydrophobicity is currently a key research focus in the field of all-solid-state ion-selective electrodes. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an all-solid-state copper ion-selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite materials, which exhibits excellent electrochemical performance. This invention also provides a method for preparing the aforementioned all-solid-state copper ion-selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite materials, as well as applications of the electrode, particularly in the detection of Cu. 2+ Applications in potentiometric sensors.

[0005] The present invention describes an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material, such as... Figure 1 As shown, it consists of a columnar conductive substrate, a solid transition layer covering the end face of the columnar conductive substrate, and a copper ion selective film covering the solid transition layer. The solid transition layer is made of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material. The thickness of the solid transition layer is 10~100μm, and the thickness of the copper ion selective film is 50~200μm.

[0006] According to some embodiments of the present invention, the columnar conductive substrate is a glassy carbon electrode (GCE).

[0007] The method for preparing an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material according to the present invention firstly involves coating a solution of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material onto one end face of a columnar conductive substrate, and drying it to form a solid transition layer covering the end face of the conductive substrate; then, a copper ion selective film covering the solid transition layer is prepared on the surface of the solid transition layer, immersed in CuCl2 aqueous solution, and then removed and allowed to air dry naturally, thereby obtaining an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material.

[0008] The solution of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material is a mixed solution of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material in ethanol, deionized water and naphthol; wherein the volume ratio of ethanol, deionized water and naphthol is 0.8~1.2:0.8~1.2:0.5, and the concentration of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material is 0.5~2 mg / mL.

[0009] In some embodiments of the present invention, the polydimethylsiloxane and amorphous hollow ZnSnO3 composite material is prepared by the following steps:

[0010] 1) Dissolve 0.5~1.0g zinc chloride (ZnCl2) and 1.5~2.0g sodium citrate (C6H5Na3O7) in 50~70mL of deionized water. Dissolve 2.0~2.5g tin tetrachloride (SnCl4) in 20~40mL of ethanol and slowly add it dropwise. Stir at room temperature to form a homogeneous solution. Then add 0.4mol / L sodium hydroxide (NaOH) solution in 125~175mL. Stir magnetically to generate an ivory-white suspension composed of solid ZnSn(OH)6 cubes.

[0011] 2) Add 2 mol / L, 90-110 mL sodium hydroxide solution to the suspension obtained in step 1) and perform alkaline-assisted etching for 20-40 minutes. After stirring for 10-20 minutes, wash with 15-25 mL of deionized water and ethanol respectively by centrifugation. Dry at 50-70℃ for 10-15 hours to obtain hollow ZnSn(OH)6 solid.

[0012] 3) The hollow ZnSn(OH)6 solid obtained in step 2) is subjected to three-step annealing and calcination in a flowing argon atmosphere to obtain an amorphous hollow ZnSnO3 solid; then, polydimethylsiloxane is deposited on the surface of the amorphous hollow ZnSnO3 solid by vapor deposition at a constant temperature of 180~220°C for 0.5~1 hours. After natural cooling to room temperature, a polydimethylsiloxane and amorphous hollow ZnSnO3 composite material (HZTO / PDMS) is obtained.

[0013] The three-step annealing and calcination temperatures are 120~180℃, 250~350℃ and 400~500℃, respectively, and the annealing and calcination time is 1.5~3.0h.

[0014] In some embodiments of the present invention, the method for preparing the copper ion selective membrane is as follows: a copper ion carrier, ion exchanger, plasticizer and polymer matrix with a total mass of 100 mg are dissolved in 1-3 mL of solvent to obtain a copper ion selective membrane solution. After thorough stirring and dissolution, the solution is coated on the surface of a solid transfer layer and air-dried to form a copper ion selective membrane. The mass ratio of copper ion carrier, ion exchanger, plasticizer and polymer matrix is ​​1:0.8-0.9:60-70:30-35, and the solvent is tetrahydrofuran (THF), dichloromethane (DCM), cyclohexanone, etc.

[0015] According to some embodiments of the present invention, the ion exchanger is sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (KTFPB), etc., the polymer matrix is ​​polyvinyl chloride (PVC), polyacrylate, etc., and the plasticizer is diisooctyl sebacate (DOS), 2-nitrophenyl octyl ether (o-NPOE), etc.

[0016] The present invention has the following beneficial effects:

[0017] This invention combines polydimethylsiloxane, which enhances the hydrophobicity of the material, with a large specific surface area amorphous hollow ZnSnO3 composite material to obtain a composite material that reduces interfacial resistance and water layer effect. Therefore, the all-solid-state ion-selective electrode prepared using polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as a solid-state transition layer exhibits excellent detection limit, sensitivity, and long-term stability, as well as superior hydrophobicity and anti-interference capabilities, maintaining optimal detection performance even under complex conditions. Furthermore, the electrode preparation process of this invention is simple, requires basic equipment, is inexpensive, and easy to store, effectively overcoming the shortcomings of existing detection methods that are expensive, technically complex, and unsuitable for field applications. It shows promising application prospects in the detection of copper ions in natural water bodies. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the all-solid-state copper ion selective electrode structure described in this invention;

[0019] Figure 2 Scanning electron microscope image of PDMS / HZTO prepared in Example 1;

[0020] Figure 3 For GC / PDMS / HZTO / Cu 2+ - Potential response curves of ISE to copper ion solutions of different concentrations; the horizontal axis represents time;

[0021] Figure 4 For GC / PDMS / HZTO / Cu 2+ - Potential correction curves of ISE for copper ion solutions of different concentrations; the horizontal axis is the logarithm of copper ion activity;

[0022] Figure 5 For GC / PDMS / SZTO / Cu 2+ - Potential response curves of ISE to copper ion solutions of different concentrations; the horizontal axis represents time;

[0023] Figure 6 GCE / Cu 2+ - Potential response curves of ISE to copper ion solutions of different concentrations; the horizontal axis represents time;

[0024] Figure 7 For GC / PDMS / HZTO / Cu 2+ -ISE, GC / PDMS / SZTO / Cu 2+ -ISE and GCE / Cu 2+ -ISE reverse timing potential curve; the horizontal axis is time;

[0025] Figure 8 For GC / PDMS / HZTO / Cu 2+-ISE and GCE / Cu 2+ -ISE electrochemical impedance spectroscopy; the horizontal axis represents the real part of the impedance;

[0026] Figure 9 For GC / PDMS / HZTO / Cu 2+ -ISE, GC / PDMS / SZTO / Cu 2+ -ISE and GCE / Cu 2+ -ISE's resistance to light interference curve; the horizontal axis represents time;

[0027] Figure 10 For GC / PDMS / HZTO / Cu 2+ -ISE, GC / PDMS / SZTO / Cu 2+ -ISE and GCE / Cu 2+ -ISE anti-interference ability curve for non-target ions; the horizontal axis is time;

[0028] Figure 11 For GC / PDMS / HZTO / Cu 2+ -ISE, GC / PDMS / SZTO / Cu 2+ -ISE and GCE / Cu 2+ -Long-term stability curve of ISE; x-axis represents time;

[0029] Figure 12 For GC / PDMS / HZTO / Cu 2+ -ISE, GC / HZTO / Cu 2+ -ISE and GCE / Cu 2+ -ISE water layer test curve; the horizontal axis represents time.

[0030] Figure 2 The data were obtained by measuring with a GRD-CS3 scanning electron microscope; Figures 3-12 All data were obtained using a three-electrode system and a Shanghai Chenhua CHI760E electrochemical workstation. Detailed Implementation

[0031] The technical solution of the present invention will be further illustrated below with reference to specific embodiments.

[0032] The reagents selected in the embodiments of the present invention are as follows:

[0033] Polydimethylsiloxane (PDMS) and ethanol were purchased from Aladdin Reagent (Shanghai) Co., Ltd.; zinc chloride, sodium citrate, sodium hydroxide, and tin tetrachloride were purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; polyvinyl chloride (PVC), naphthol, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), diisooctyl sebacate (DOS), tetrahydrofuran, and copper ion carrier were purchased from Fluka (model "Carrier I"). All reagents used were of analytical grade, and deionized water was used in the experiments.

[0034] The polishing method for glassy carbon electrodes in this embodiment of the invention includes the following steps:

[0035] The end face of the glassy carbon electrode was successively ground and polished with Al2O3 microspheres with a particle size of 0.3 μm and 0.05 μm until the surface was smooth. Then, it was placed in deionized water, ethanol solution and deionized water for ultrasonic treatment for 10 seconds each time, thus obtaining a glassy carbon electrode with polished end face.

[0036] Example 1

[0037] A method for preparing an all-solid-state copper ion-selective electrode includes the following steps:

[0038] S1. Preparation of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material: 0.82g zinc chloride and 1.76g sodium citrate were dissolved in 60mL deionized water, and 2.10g tin tetrachloride was dissolved in 30mL ethanol and slowly added dropwise. The mixture was stirred at room temperature to form a homogeneous solution. Then, 0.4mol / L, 150mL sodium hydroxide solution was added dropwise and the mixture was magnetically stirred to generate an ivory-white suspension composed of solid ZnSn(OH)6 cubes. Subsequently, 2 mol / L, 100 mL sodium hydroxide solution was added for alkali-assisted etching for 30 minutes. After stirring for another 15 minutes, the solid was washed with 20 mL deionized water and ethanol by centrifugation and dried at 60 °C for 12 hours to obtain hollow ZnSn(OH)6 solid. Finally, the solid was annealed and calcined at 150 °C, 300 °C, and 450 °C for 2 hours under an argon atmosphere to obtain amorphous hollow ZnSnO3 solid. Polydimethylsiloxane was deposited on the surface of the amorphous hollow ZnSnO3 solid heated at 200 °C for 60 minutes using chemical vapor deposition. Specifically, the chemical vapor deposition instrument was heated at 200 °C for 60 minutes to deposit polydimethylsiloxane. After the instrument cooled naturally, the product was removed. The obtained product is polydimethylsiloxane and amorphous hollow ZnSnO3 composite material (PDMS / HZTO), with a product mass of 1.2 g.

[0039] S2. Preparation of copper ion selective membrane solution: Weigh 65.7g of DOS, 32.9g of PVC, 1.0g of copper ion carrier and 0.86g of NaTFPB, dissolve in 1mL of THF, stir to dissolve and store in a glass bottle, seal and refrigerate in a refrigerator.

[0040] S3. Preparation of copper ion selective electrode: Weigh 5 mg of PDMS / HZTO prepared in step S1 and dissolve it in a mixed solution of 200 μL ethanol, 200 μL deionized water, and 100 μL naphthol. Shake well and sonicate for 10 min to obtain a PDMS / HZTO mixed solution. Use a pipette to drop this mixed solution onto the prepared glassy carbon electrode end face (glassy carbon electrode diameter is 5 mm), and allow it to air dry naturally to obtain a PDMS / HZTO solid transition layer with a thickness of 20 μm covering the conductive substrate end face. Then, use a pipette to drop the copper ion selective membrane solution prepared in step S2 onto the surface of the PDMS / HZTO solid transition layer, and air dry to form a copper ion selective membrane with a thickness of 20 μm. Then, place the obtained electrode into a 1.0 × 10⁻⁶ ohmmeter. -3 mol L -1 After soaking in an aqueous CuCl2 solution for 24 hours, the electrode was removed and allowed to air dry, resulting in an all-solid-state copper ion-selective electrode, denoted as GC / PDMS / HZTO / Cu. 2+ -ISE.

[0041] Example 2

[0042] The difference between this embodiment and Embodiment 1 is that the PDMS / HZTO in step S3 of Embodiment 1 is replaced with an equal mass of polydimethylsiloxane and amorphous solid ZnSnO3 composite material (PDMS / SZTO). The other steps are the same as in Embodiment 1, resulting in an all-solid-state copper ion-selective electrode, denoted as GC / PDMS / SZTO / Cu. 2+ -ISE.

[0043] The preparation of the polydimethylsiloxane and amorphous solid ZnSnO3 composite material (SZTO) involves dissolving 0.82g of zinc chloride and 1.76g of sodium citrate in 60mL of deionized water, while simultaneously dissolving 2.10g of tin tetrachloride in 30mL of ethanol and slowly adding the solution dropwise, stirring at room temperature to form a homogeneous solution; then adding 0.4mol / L, 150mL of sodium hydroxide solution, and magnetically stirring to generate an ivory-white suspension composed of solid ZnSn(OH)6 cubes. Finally, the solid ZnSnO3 was annealed and calcined sequentially at 150℃, 300℃, and 450℃ for 2 hours under an argon atmosphere to obtain amorphous solid ZnSnO3. Polydimethylsiloxane was deposited on the surface of the solid ZnSnO3 heated at 200℃ for 60 minutes using vapor deposition. Specifically, the vapor deposition instrument was heated at 200℃ for 60 minutes to deposit polydimethylsiloxane. After the instrument cooled naturally, the product was removed. The obtained product is the polydimethylsiloxane and solid ZnSnO3 composite material (PDMS / SZTO), with a product mass of 1.2 g.

[0044] Example 3

[0045] The difference between this embodiment and Embodiments 1 and 2 is that the copper ion selective membrane solution prepared in step S2 of Embodiment 1 is directly dropped onto the prepared glassy carbon electrode end face using a pipette and allowed to air dry, resulting in a copper ion selective membrane with a thickness of 20 μm covering the conductive substrate. This membrane serves as the all-solid-state copper ion selective electrode and is denoted as GCE / Cu. 2+ -ISE.

[0046] Performance testing

[0047] Using the ion-selective electrode prepared in Examples 1-2 of this invention as the working electrode, platinum wire as the counter electrode, and Ag|AgCl (3M KCl) as the reference electrode, a method for detecting Cu was prepared. 2+ The sensor is a potentiometric type; all electrochemical tests were performed using a three-electrode system and a Shanghai Chenhua CHI760E electrochemical workstation.

[0048] The prepared PDMS / HZTO material was characterized using scanning electron microscopy (SEM), and the test results are shown in the figure. Figure 2 The microstructure of PDMS / HZTO is shown to be a cubic structure with a rough surface and clear boundaries. Its particle size is 900 nm.

[0049] Using the open-circuit potential detection method, the electrodes from Examples 1 and 2 were placed in a copper ion concentration of 1.0 × 10⁻⁶. -1 -1.0×10 -10 mol·L -1 The test is conducted in a solution. For example... Figure 3 and Figure 4As shown, GC / PDMS / HZTO / Cu 2+ -ISE has a detection range of 10. -10 ~10 -1 mol·L -1 The detection limit is 10. -7.99 mol·L -1 The sensitivity is 26.88 ± 0.2 mV / dec; Figure 5 and Figure 6 As shown, GC / PDMS / SZTO / Cu 2+ -ISE detection range is 10 -1 ~10 -5 mol·L -1 GCE / Cu 2+ -ISE detection range is 10 -1 ~10 -6 mol·L -1 In comparison, GC / PDMS / HZTO / Cu 2+ -ISE outperforms GC / PDMS / SZTO / Cu in terms of detection limit. 2+ -ISE and GCE / Cu 2+ -ISE electrode.

[0050] The short-term stability of the electrodes was characterized using the reverse chronopotential method. For example... Figure 7 As shown, when the applied current remains constant at 1 nA, GCE / Cu can be calculated using the formula ΔE / Δt (where ΔE is the voltage difference between the start and end of the measurement, and Δt is the measurement time of 200 seconds). 2+ The potential drift of -ISE is 3.5 × 10⁻⁶. -5 V / s, GC / PDMS / SZTO / Cu 2+ The potential drift of -ISE is 2.9 × 10⁻⁶. -5 V / s, GC / PDMS / HZTO / Cu 2+ The potential drift of -ISE is 2.0 × 10⁻⁶. -5 V / s. According to the formula I=C×ΔE / Δt (where I is the applied current 1nA and C is the capacitance), GCE / Cu can be calculated. 2+ The capacitance of -ISE is 28.57μF, GC / PDMS / SZTO / Cu 2 + The capacitance of -ISE is 34.48μF, GC / PDMS / HZTO / Cu 2+ The capacitance value of -ISE is 50.00 μF, indicating that GC / PDMS / HZTO / Cu 2+ -ISE electrodes have better potential stability.

[0051] The electrochemical impedance performance of the electrodes was tested. For example... Figure 8 As shown, GC / PDMS / HZTO / Cu 2+ -ISE and GCE / Cu 2+ The high-frequency resistances of -ISE are 5.1 MΩ and 1.2 MΩ, respectively. PDMS / HZTO, as a solid-state transition layer, significantly reduces the interface resistance, indicating that GC / PDMS / HZTO / Cu... 2+ -ISE has better specific capacitance performance than GCE / Cu. 2+ -ISE.

[0052] Electrode stability was tested under different lighting conditions. The lighting sequence was dark, light, UV light, and light again, switching every 500 seconds. Figure 9 It can be seen that compared to the other two electrodes, GC / PDMS / HZTO / Cu 2+ -ISE was almost completely unaffected, indicating that GC / PDMS / HZTO / Cu 2 + -ISE has better photostability and anti-interference capabilities.

[0053] Electrode resistance to non-target ion interference testing, such as Figure 10 As shown, by using 1.0×10 -1 mol·L -1 A solution of nickel chloride, barium chloride, chromium chloride, calcium chloride, and magnesium chloride was added dropwise to a solution of 1.0 × 10⁻⁶. -1 mol·L -1 Anti-interference tests were performed in copper chloride solution, and no GC / PDMS / HZTO / Cu were observed. 2+ - A significant potential drift was observed in the ISE. This demonstrates that the introduction of PDMS / HZTO as a solid-state transition layer effectively reduces the influence of interfering ions on the copper ion detection results, thereby improving the reliability of the electrode.

[0054] The long-term stability of the electrode was tested using the open-circuit potential method. The electrode was placed in a copper ion concentration of 1.0 × 10⁻⁶. -1 mol·L -1 In the solution for 12 hours, such as Figure 11 As shown, GC / PDMS / HZTO / Cu 2+ The potential drift of the -ISE electrode is only 1.25 mV / h, and its potential stability is superior to the other two electrodes, indicating that the GC / PDMS / HZTO / Cu electrode combination exhibits better performance. 2+ -ISE has better potential stability.

[0055] The hydrophobicity of the electrode was tested. In this experiment, the electrode was first placed in a solution with a concentration of 0.1 mol·L⁻¹. -1 In a copper chloride solution for 2 hours, then in a 0.1 mol·L⁻¹ solution. -1 The test was conducted in sodium chloride solution for 4 hours, and finally in 0.1 mol·L⁻¹ solution. -1 The potential change curve is shown in the copper chloride solution after 8 hours of testing. Figure 12 As shown, GCE / Cu 2+ -ISE retains its initial potential but exhibits continuous drift, GC / PDMS / HZTO / Cu 2+ -ISE potential remained stable throughout the test. Polydimethylsiloxane combined with amorphous hollow ZnSnO3 enhances the hydrophobicity of the material itself, preventing the formation of a water layer.

[0056] In summary, the copper ion selective electrode GC / PDMS / HZTO / Cu prepared by this invention... 2+ The -ISE exhibits a good Nernst response curve, excellent sensitivity and potential stability, and superior hydrophobicity and anti-interference capabilities, allowing for storage and measurement even in complex environments. Furthermore, the sensor prepared by this invention is small in size, simple to operate, and low in cost, making it more suitable for large-scale industrial production. The copper ion selective electrode of this invention has broad application prospects in the field of copper ion detection in industrial wastewater.

[0057] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an all-solid-state copper ion-selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material, characterized in that: First, a solution of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material is coated onto one end face of a columnar conductive substrate and dried to form a solid transition layer covering the end face of the conductive substrate. Then, a copper ion selective film covering the solid transition layer is prepared on the surface of the solid transition layer, immersed in CuCl2 aqueous solution, and then taken out and air-dried to obtain an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material.

2. The method for preparing an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as described in claim 1, characterized in that: The columnar conductive substrate is a glassy carbon electrode.

3. The method for preparing an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as described in claim 1, characterized in that: The solution of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material is a mixed solution of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material in ethanol, deionized water and naphthol; wherein the volume ratio of ethanol, deionized water and naphthol is 0.8~1.2:0.8~1.2:0.5, and the concentration of polydimethylsiloxane and amorphous hollow ZnSnO3 composite material is 0.5~2 mg / mL.

4. The method for preparing an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as described in claim 1, characterized in that: The polydimethylsiloxane and amorphous hollow ZnSnO3 composite material was prepared by the following steps. 1) Dissolve 0.5~1.0g zinc chloride and 1.5~2.0g sodium citrate in 50~70mL deionized water, dissolve 2.0~2.5g tin tetrachloride in 20~40mL ethanol and slowly add it dropwise, stirring at room temperature to form a homogeneous solution; then add 0.4mol / L, 125~175mL sodium hydroxide solution, and stir magnetically to generate an ivory-white suspension composed of solid ZnSn(OH)6 cubes; 2) Add 2 mol / L, 90-110 mL sodium hydroxide solution to the suspension obtained in step 1) and perform alkaline-assisted etching for 20-40 minutes. After stirring for 10-20 minutes, wash with 15-25 mL of deionized water and ethanol respectively by centrifugation. Dry at 50-70℃ for 10-15 hours to obtain hollow ZnSn(OH)6 solid. 3) The hollow ZnSn(OH)6 solid obtained in step 2) is subjected to three-step annealing and calcination in a flowing argon atmosphere to obtain an amorphous hollow ZnSnO3 solid; then, polydimethylsiloxane is deposited on the surface of the amorphous hollow ZnSnO3 solid by vapor deposition at a constant temperature of 180~220°C for 0.5~1 hours. After natural cooling to room temperature, a polydimethylsiloxane and amorphous hollow ZnSnO3 composite material is obtained.

5. The method for preparing an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as described in claim 4, characterized in that: The three-step annealing and calcination temperatures are 120~180℃, 250~350℃ and 400~500℃, respectively, and the annealing and calcination time is 1.5~3.0h.

6. The method for preparing an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as described in claim 1, characterized in that: A copper ion-selective membrane solution was obtained by dissolving 100 mg of copper ion carrier, ion exchanger, plasticizer and polymer matrix in 1-3 mL of solvent. After thorough stirring and dissolution, the solution was coated on the surface of a solid transfer layer and air-dried to form a copper ion-selective membrane. The mass ratio of copper ion carrier, ion exchanger, plasticizer and polymer matrix was 1:0.8-0.9:60-70:30-35.

7. The method for preparing an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as described in claim 6, characterized in that: The solvent is tetrahydrofuran, dichloromethane, or cyclohexanone; the ion exchanger is sodium tetra[3,5-di(trifluoromethyl)phenyl]borate or potassium tetra[3,5-di(trifluoromethyl)phenyl]borate; the polymer matrix is ​​polyvinyl chloride or polyacrylate; and the plasticizer is diisooctyl sebacate or 2-nitrophenyl octyl ether.

8. The method for preparing an all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as described in claim 1, characterized in that: The thickness of the solid-state transition layer is 10~100μm, and the thickness of the copper ion selective film is 50~200μm.

9. A fully solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 8.

10. The all-solid-state copper ion selective electrode based on polydimethylsiloxane and amorphous hollow ZnSnO3 composite material as described in claim 9 for detecting Cu 2+ Applications in potentiometric sensors.

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