CN114544730A

CN114544730A - Ion sensor and preparation method and application thereof

Info

Publication number: CN114544730A
Application number: CN202210151157.9A
Authority: CN
Inventors: 刘英菊; 敖日其冷; 刘伟鹏; 彭海华; 梁弘志
Original assignee: South China Agricultural University
Current assignee: South China Agricultural University
Priority date: 2022-02-15
Filing date: 2022-02-15
Publication date: 2022-05-27
Anticipated expiration: 2042-02-15
Also published as: CN114544730B

Abstract

The invention discloses an ion sensor and a preparation method and application thereof, wherein the ion sensor comprises a working electrode and a reference electrode, the working electrode is a processed PCB electrode covered with an ion selective membrane, and Au NBS and PEDOT are modified on the PCB electrode: PSS. According to the ion sensor of some examples of the invention, the PCB is directly used as an electrode, and the nano-gold material with a branched structure is electrodeposited on the surface, so that the electrochemical performance of the surface of the electrode is improved, and a stable electrochemical signal is acquired. By modifying different types of solid ion selective membranes, a multi-channel solid ion selective electrode with lower price, wider detection range, high sensitivity and high detection limit can be constructed.

Description

Ion sensor and preparation method and application thereof

Technical Field

The invention belongs to the field of detection, and particularly relates to an ion sensor and a preparation method and application thereof.

Background

In recent years, with the improvement of living standard, people have increasingly demanded environment, and particularly pay attention to water environment. This is because many elements commonly found in water have a great influence on the environment and living things, including potassium, calcium, sodium, magnesium, chlorine, nitrate ions, etc. For example, irrigation of land with an excess of alkali metal over a long period of time may cause salinization of the land. If animals drink water sources with excessive calcium, sodium and magnesium ions for a long time, developmental deformity can be caused, and plants growing depending on the water sources can grow slowly. For human bodies, a series of hazards are brought, for example, high potassium can cause arrhythmia; excessive sodium can cause edema and hypertension; ectopic deposition of calcium is easy to occur when blood calcium is increased, and urinary calculus is possibly caused by deposition in kidney. In addition, the method can cause the blockage of pipelines in industrial production, and generates direct economic loss. For the above ions, conventional detection methods include chromatography, atomic absorption spectrometry, titration, and the like. These methods are time-consuming and labor-intensive, require specialized personnel to operate, and require expensive instrumentation, and most importantly, these methods are difficult to meet the requirements for rapid field testing, including: the detection cost is low, the operation is simple, convenient and intelligent, and the monitoring is rapid and sensitive.

The ion selective electrode can realize the high-sensitivity and high-selectivity rapid detection of corresponding ions in a solution. In the solid ion selective electrode which is developed rapidly in recent years, the traditional liquid contact type ion selective electrode is replaced by the solid conducting layer body, and the internal filling liquid and the internal reference electrode in the ion selective electrode are replaced, so that the ion selective electrode has the advantages of convenience in preparation and maintenance, easiness in miniaturization, strong portability, easiness in production and the like. Particularly, the solid-state ion selective electrode is combined with portable wireless detection equipment, so that the ions can be rapidly, highly sensitively and timely monitored. Although these devices have been widely used, the electrodes are generally expensive to manufacture and complicated to manufacture, for example, the photolithography process is expensive in equipment, complicated in manufacturing process, and high in cost. Therefore, the electrode surface is improved by other ways, for example, the electrode surface is modified by synthesizing nano materials with larger specific surface area, the electrode performance is changed, the electric signal is more stable, and the detection sensitivity is improved.

The development of the low-cost and high-sensitivity ion sensor has very important significance for realizing low-cost and quick ion content detection.

Disclosure of Invention

The present invention aims to overcome at least one of the disadvantages of the prior art and to provide an ion sensor, a method for producing the same and use thereof.

The technical scheme adopted by the invention is as follows:

in a first aspect of the present invention, there is provided:

an ion sensor comprises a working electrode and a reference electrode, wherein the working electrode is a processed PCB electrode covered with an ion selective membrane, and a nano gold branch Au NBS and a conductive polymer membrane PEDOT are modified on the PCB electrode: PSS.

In some ion sensor examples, there are at least 2 sets of working and reference electrodes, with different working electrodes covered with ion selective membranes for different ions.

In some ion sensor examples, the ion selective membrane is selected from Na⁺Selective membranes, K⁺Selective Membrane, Ca²⁺Selective film, Mg²⁺Selective membrane, NO₃ ^-Selective membranes and Cl^-At least one of selective membranes.

In some examples of ion sensors, the reference electrode is an Ag/AgCl electrode.

In a second aspect of the present invention, there is provided:

the preparation method of the ion sensor in the first aspect of the invention comprises the following steps:

cleaning PCB electrode, and soaking in HAuCl₄And H₂SO₄In the mixed solution, performing electrodeposition Au NBS on the surface of the PCB electrode, and cleaning to obtain an intermediate electrode A;

soaking the intermediate electrode A in a mixed solution of 3, 4-ethylenedioxythiophene EDOT and sodium polystyrene sulfonate NaPSS, wherein the intermediate electrode A is a working electrode, and electrodepositing a conductive polymer film PEDOT: PSS to obtain an intermediate electrode B;

and dropwise adding an ion selective membrane solution on the intermediate electrode B, drying, and forming an ion selective membrane on the surface of the intermediate electrode B to obtain the ion sensor.

In some examples of the preparation method, the voltage of electrodeposited Au NBS is-0.8V to 0.2V.

In some examples of the preparation method, the cycle number of the electrodeposition of Au NBS is 30-50 times.

In some examples of the preparation method, HAuCl₄The concentration of (B) is 0.001-0.005M.

In some examples of the preparation, H₂SO₄The concentration of (A) is 0.2-0.8M.

In some examples of the preparation method, the concentration of EDOT is 0.01-0.05M.

In some examples of the preparation method, the concentration of NaPSS is 0.1-0.3M.

In some examples of the preparation method, the electrodeposition time of the intermediate electrode A is 50 to 200 s.

In some examples of the preparation method, the current density of the electrodeposition of the intermediate electrode A is 0.5-2.5 mA/cm²。

In some examples of the preparation method, the counter electrode for electrodeposition of Au NBS is a Pt electrode and the reference electrode is a calomel electrode.

In some examples of the preparation method, the counter electrode is a Pt electrode and the reference electrode is an Ag/AgCl electrode when the intermediate electrode A is subjected to electrodeposition.

In some examples of the preparation method, the reference electrode of the ion sensor is an Ag/AgCl electrode, and the reference electrode is obtained by dripping Ag/AgCl slurry on the surface of a PCB electrode, heating, fixing, drying, dripping a mixed solution containing polyvinyl butyral PVB or polyvinyl chloride PVC, and drying; the mixing ratio of the mixed solution is as follows: 1-3 mL of methanol, 50-90 mg of PVB or PVC, 30-70 mg of NaCl or KCl, 1-5 mg of PEO-PPO-PEO (F127) and 0.1-0.5 mg of carbon tubes.

In some examples of the production method, the carbon tube has a length of 20 to 500 nm.

In a third aspect of the present invention, there is provided:

a portable ion detector comprising an ion sensor according to the first aspect of the invention, or an ion sensor produced by a method according to the second aspect of the invention.

The invention has the beneficial effects that:

according to the ion sensor of some examples of the invention, the PCB is directly used as an electrode, and the nano-gold material with a branched structure is electrodeposited on the surface, so that the electrochemical performance of the surface of the electrode is improved, and a stable electrochemical signal is acquired.

The ion sensor of some examples of the invention modifies different types of solid ion selective membranes simultaneously, and constructs a multi-channel solid ion selective electrode with lower price, wider detection range, high sensitivity and high detection limit.

The preparation method of some embodiments of the invention has simple process, and can prepare stable and reliable ion sensors.

The portable ion detector of some embodiments of the invention has the functions of multi-channel signal acquisition, amplification, filtration and transmission, can receive signals in real time and display APP of corresponding results, and can simultaneously detect Na in water⁺，K⁺，Ca²⁺，Mg²⁺，NO₃ ^-，Cl^-The plasma detection device has the advantages of low cost, high efficiency, high speed, high sensitivity and high detection limit.

Drawings

FIG. 1 is a circuit diagram of ion detection with two detection channels;

fig. 2 is an SEM image of each step of PCB electrode synthesis, in which (a) Au NBS, (B) PEDOT: PSS, (C) ionic membrane;

FIG. 3 is Na⁺（A，B）、Ca²⁺（C，D）、NO₃ ^-Potential response graphs and standard graphs of the solid ion-selective electrodes of (E, F).

FIG. 4 is K⁺（A，B）、Mg²⁺（C，D）、Cl^-Potential response graphs and standard graphs of the solid ion-selective electrodes of (E, F).

Detailed Description

According to the invention, the reaction conditions are controlled, Au NBS with high specific surface area is modified on the PCB electrode to improve the electrode performance, increase the capacitance of the solid ion selective electrode, reduce the influence of a water layer on the electrode, and finally improve the stability of signal acquisition. By modification of PEDOT: PSS, promote electron transfer rate, promote signal sensitivity.

Construction of lower valency by modification of different types of solid ion-selective membranesThe multi-channel solid-state ion selective electrode has wide detection range, high sensitivity and high detection limit. In addition, the handheld detection equipment with multichannel signal acquisition, amplification, filtration and transmission is constructed, APP capable of receiving signals in real time and displaying corresponding results is designed, and finally Na in water can be simultaneously detected through construction⁺，K⁺，Ca²⁺，Mg²⁺，NO₃ ^-，Cl^-The plasma detection device has the advantages of low cost, high efficiency, high speed, high sensitivity and high detection limit.

In a first aspect of the present invention, there is provided:

an ion sensor comprises a working electrode and a reference electrode, wherein the working electrode is a processed PCB electrode covered with an ion selective membrane, and Au NBS and PEDOT are modified on the PCB electrode: PSS.

In some ion sensor examples, there are at least 2 sets of working and reference electrodes, with different working electrodes covered with ion selective membranes for different ions. Of course, the same ion selective membrane may be provided to obtain more accurate detection results.

The ion selective membrane may be configured as desired to satisfy detection of the corresponding ions. In some ion sensor examples, the ion selective membrane is selected from Na⁺Selective membranes, K⁺Selective Membrane, Ca²⁺Selective film, Mg²⁺Selective membrane, NO₃ ^-Selective membranes and Cl^-At least one of selective membranes.

The reference electrode is only required to be capable of stably providing corresponding reference potential, and the type of the reference electrode has no special requirement. In some examples of ion sensors, the reference electrode is an Ag/AgCl electrode. The reference electrode is stable and reliable, and the cost is low.

In a second aspect of the present invention, there is provided:

s1) cleaning the PCB electrode, and immersing in HAuCl₄And H₂SO₄In the mixed solution, electricity is generated on the surface of the PCB electrodeDepositing Au NBS, and cleaning to obtain a middle electrode A;

s2) immersing the intermediate electrode a in a mixed solution of EDOT and NaPSS, the intermediate electrode a being a working electrode, electrodepositing PEDOT: PSS to obtain an intermediate electrode B;

s3) adding the ion selective membrane solution to the intermediate electrode B, drying, and forming an ion selective membrane on the surface of the intermediate electrode B to obtain the ion sensor.

In some examples of the preparation method, the reference electrode of the ion sensor is an Ag/AgCl electrode, and the reference electrode is obtained by dripping Ag/AgCl slurry on the surface of a PCB electrode, heating, fixing, drying, dripping a mixed solution containing PVB or PVC, and drying; the mixing ratio of the mixed solution is as follows: 1-3 mL of methanol, 50-90 mg of PVB or PVC, 30-70 mg of NaCl or KCl, 1-5 mg of F127 and 0.1-0.5 mg of carbon tube.

In a third aspect of the present invention, there is provided:

a portable ion detector comprising an ion sensor according to the first aspect of the invention.

The technical scheme of the invention is further explained by combining experiments.

Preparation of solutions

Na⁺The selective membrane mixture consists of 2-8 mg of a sodium ion carrier, 2-8 mg of sodium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate (Na-TFPB, 2-8 mg), 100-200 mg of polyvinyl chloride (PVC) and 200-300 mg of diisooctyl sebacate (DOS), and 300-500 mg of the membrane mixture is dissolved in 2-4 mL of tetrahydrofuran.

K⁺The selective membrane mixture consists of valinomycin (2-8 mg), sodium tetraphenylborate (Na TPB, 2-8 mg), PVC (100-200 mg) and DOS (200-300 mg) in weight, and 300-500 mg of the membrane mixture is dissolved in 0.5-2 mL of cyclohexanone.

Ca²⁺The selective membrane mixture consists of 2-8 mg of calcium ion carrier, 2-8 mg of Na-TFPB (sodium-perfluorooctanoate-TFPB), 100-200 mg of PVC (polyvinyl chloride) and 200-300 mg of DOS (dimethyl disulfide) by weight, and 300-500 mg of the membrane mixture is dissolved in 1-4 mL of tetrahydrofuran.

Mg²⁺The selective membrane mixture consists of 2-8 mg of magnesium ion carrier (magnesium ion carrier), 20-80 mg of o-nitrophenyloctyl ether (NOPE), 20-80 mg of PVC (polyvinyl chloride) and 10-50 mg of KTClPB (potassium tetranitrodiphenyl phosphate), and 50-250 mg of the membrane mixture is dissolved in 1-3 mL of tetrahydrofuran.

NO₃ ^-The selective membrane mixture consists of 2-5 mg of nitric acid ion carrier, 2-5 mg of Na-TFPB (sodium-dimethyl-phthalate), 20-60 mg of PVC (polyvinyl chloride) and 40-80 mg of DOS (dimethyl disulfide) by weight, and 50-150 mg of the membrane mixture is dissolved in 2-4 mL of tetrahydrofuran.

Cl^-The selective membrane is prepared from an Ag/AgCl slurry.

Polyvinyl butyral resin (PVB) or polyvinyl chloride (PVC) solution is prepared by dissolving 50-90 mg of PVB or PVC, 30-70 mg of NaCl or KCl, 1-5 mg of PEO-PPO-PEO (F127) and 0.1-0.5 mg of carbon tubes (20-500 nm) in 1-3 mL of methanol.

Electrode preparation

Preparing a working electrode:

s1) carrying out ultrasonic treatment on the PCB electrodes in water, ethanol and acetone solutions for 20 min respectively, and washing the PCB electrodes with distilled water for later use. Immersing the electrode in 0.001-0.005 mol/L HAuCl₄And 0.2 to 0.8 mol/L H₂SO₄In the mixed solution, a PCB electrode is used as a working electrode, a Pt electrode is used as a counter electrode, a calomel electrode is used as a reference electrode, and 40 cycles are carried out under the condition of-0.8V-0.2V to prepare an Au NBS modified intermediate electrode A;

s2) cleaning the middle electrode A with distilled water, soaking the electrode in 0.01-0.05M EDOT and 0.1-0.3M NaPSS solution, taking a PCB electrode as a working electrode, a Pt electrode as a counter electrode, an Ag/AgCl electrode as a reference electrode, and performing electrochemical reaction at a current density of 0.5-2.5 mA/cm²Carrying out lower electrodeposition for 50-200 s to obtain a middle electrode B;

s3) adding 1-6 mu L of corresponding ionic membrane solution into the middle electrode B, drying in the air at normal temperature for 24 h, and storing in a refrigerator at 4 ℃.

Soaking in water at a concentration of 10^-6 M Na⁺、K⁺、Ca²⁺、Mg²⁺、NO₃ ^-、Cl^-The ionic membrane is activated for 1 h in the mixed solution.

Preparing a reference electrode:

and dripping Ag/AgCl slurry on the surface of the PCB electrode, heating to 80 ℃ on a heating plate, drying for 1 h, dripping 2-6 mu L of PVB or PVC solution, and drying for 24 h at room temperature.

Device development

The signal acquisition circuit diagram is designed as shown in figure 1. The portable electrochemical detection device is assembled according to the existing method. Or assembled with reference to the following methods:

the multichannel electrochemical detection device comprises an Atmega328P-AU microcontroller, a multichannel micro-voltage acquisition circuit, a data transmission module and a man-machine interaction module which jointly form a detection system, wherein: two electrode systems are adopted for signal acquisition, and the whole signal acquisition module comprises: (1) the device comprises an electrode interface, (2) reference voltage signal acquisition, (3) a voltage follower, (4) a differential proportional operation circuit, and (5) a filter circuit. The amplification circuit chips all adopt LT 1462. The voltage follower is used for enhancing the load capacity of the DAC output, the differential proportional operation circuit is used for deducting reference voltage and simultaneously achieving signal amplification, and the low-pass filter can convert the filtered analog signals into digital forms and transmit the digital forms to the microcontroller (6).

The data transmission module comprises (7) a communication serial port, (8) a system loading interface and (9) a program code input port. Serial communication and Bluetooth communication can be realized through the communication serial port, bottom layer languages of the chip can be conveniently replaced through the system loading interface, and codes can be rapidly updated through the program code input port.

In order to facilitate detection, the man-machine interaction module uses Bluetooth to realize signal transmission between the mobile phone and the detection equipment, each ion concentration signal is directly read through the mobile phone, meanwhile, the detection result is corrected through inputting a temperature signal, and a corresponding correction result is quickly obtained.

Results and discussion

Electrode characterization and Performance

The purchased PCB electrodes have been surface deposited with gold. In order to improve the electrochemical performance of the electrode, Au NBS is modified on the surface of the electrode in an electrochemical deposition mode. Fig. 2A shows the microstructure of Au NBS on the electrode surface. In order to further improve the stability of the electrode in the testing process and reduce the potential drift of the electrode, a layer of PEDOT is deposited on the surface of the electrode: PSS, promote electron transfer rate. The morphology is shown in fig. 2B, which shows that a uniform and flat film is decorated on the electrode surface, and the Au NBS of the bottom layer can still be seen. Finally, the corresponding ionic membrane solution is dripped on the surface of the working electrode. FIG. 2C shows the appearance of the electrode after dropping the ionic membrane on the electrode, wherein the ionic membrane completely covers the surface of the electrode.

And comparing and researching the electrochemical performance of the solid contact type ion selective electrode of the Au NBS transduction layer by adopting electrochemical impedance measurement and cyclic voltammetry to evaluate the mechanism of improving the electrode performance of the Au NBS. For solid contact ion-selective electrodes, the ion-electron conductivity between the conductive substrate and the polymer membrane is affected by the loading of the ion-electron transfer layer. The number of turns of electrodeposition will affect the thickness and number of branches of the Au NBS structure and therefore the PEDOT: the thickness of PSS, thereby affecting the electrochemical performance of the entire electrode. The Au-PCB electrode and the Au NBS deposited in different turns are characterized by cyclic voltammetry, and the optimum turn for the Au NBS electrodeposited by the Au-PCB electrode is 40 turns. The electrochemical impedance test of the corresponding electrode shows that the Au NBS structure and the PEDOT: the introduction of PSS, the high-frequency resistance of the solid-state ion-selective electrode was effectively reduced, which indicates that the Au NBS structure of the ion-electron transport layer and PEDOT: PSS reduces the charge transfer resistance between the solid conductive substrate and the polymeric ion-selective membrane.

To evaluate the solid contact layer Au NBS structure and PEDOT: the influence of PSS on the capacitance of the ion-selective electrode was examined, and the stability of the prepared electrode was examined, and the potential change of the electrode was examined by applying a current of ± 1 n A to the electrode. In the chronopotentiometry, the change in potential with time (Δ E/Δ t) was used as an important index for evaluating the stability of the electrode. With Au NBS structure and PEDOT: the introduction of PSS, the capacitance of the ion selective electrode increases. Therefore, Au NBS structure and PEDOT: the introduction of the PSS transduction layer can obviously improve the stability of the solid-state ion selective electrode.

On the other hand, the water layer existing between the polymer ion selective membrane and the solid conductive substrate can significantly influence the potential stability of the solid ion selective electrode, so that a water layer test experiment is the key for performance investigation of the solid contact type ion selective electrode. If the water layer exists, the positive potential drift can occur when the electrode moves from the main ion solution to the interference ion solution; when the electrode is transferred from the interfering ion solution back to the main ion solution, a negative potential drift occurs. Experiments show that the solid transfer layer Au NBS structure and PPEDOT: after PSS introduction, there was almost no potential shift, indicating Au NBS structure and PEDOT: PSS can effectively reduce the existence of a water layer in the solid-state ion selective electrode.

Electrode performance testing

FIG. 3 is Na⁺（A，B）、Ca²⁺（C，D）、NO₃ ^-Potential response graphs and standard graphs of the solid ion-selective electrodes of (E, F). FIG. 4 is K⁺（A，B）、Mg²⁺（C，D）、Cl^-Potential response graphs and standard graphs of the solid ion-selective electrodes of (E, F). Before detection, the ionic membrane to be detected is firstly soaked in a solution containing 10^-6M is activated for 1 hour in the solution of the detected ions and then sequentially activated at each ion concentration of 10^-1 - 10^-6M in solution. As can be seen from fig. 3 and 4, the solid-state ion-selective electrode has a fast response speed, and the time for reaching potential equilibrium in different ionic solutions is different. Except for Na⁺And K⁺And the potential equilibrium response time of most ionic membranes is less than 5 s. Meanwhile, the prepared novel solid contact type ion selective electrode has stable response to the concentration change. Each ion-selective electrode is selective to a corresponding ion such as Na⁺、K⁺、Ca²⁺、Mg²⁺、NO₃ ^-、Cl^-Are all at 10^-1 - 10^-4M shows a good linear relationship. Reproducibility of ion-selective electrodes is an important parameter for evaluating ion-selective electrodes. Na (Na)⁺、K⁺、Ca²⁺、Mg²⁺、NO₃ ^-By containing respective detection ions 10^-1 - 10^-4M and buffer solution are switched, and the reproducibility of ion selective electrode signals and the stability of the electrodes are evaluated. Wherein the buffer solution contains 10^-6M solution of ions to be detected and buffer solution can play a role in balancing potential again, so that the reproducibility of signals is improved. Due to Cl^-The selective electrode has no organic ionic membrane structure and is therefore at 10^-1 - 10^-4The M chloride ion solution is switched without entering the buffer solution again. Each ion selective electrode exhibited good signal reproducibility when detected for 2500 seconds.

Temperature is also one of the factors that affect the performance of the ionic membrane. To investigate the effect of temperature on the ionic membrane, Na⁺、K⁺、Ca²⁺、Mg²⁺、NO₃ ^-、Cl^-In the ion selective electrode containing 10^-2And M, carrying out ion dynamic potential detection in the solution of ions to be detected at the temperature of between 25 ℃ and 45 ℃. The results show that the ion dynamic potential of all the ion membranes gradually decreases with increasing temperature, which is caused by the gradual increase of the resistance of the ion membranes. Meanwhile, in the range of 25 ℃ to 45 ℃, the ion dynamic potential and the temperature show a good linear relation, and a temperature adjustment curve is obtained. Although the potential change due to the temperature influence is relatively small with respect to the potential change due to the concentration change, more accurate results can be obtained after correction according to the temperature. Therefore, the corrected ion concentrations can be directly obtained by inputting the correction curve into the device and inputting the correction curve into the APP according to the temperature displayed by the sensor.

The foregoing is a more detailed description of the invention and is not to be taken in a limiting sense. It will be apparent to those skilled in the art that simple deductions or substitutions without departing from the spirit of the invention are within the scope of the invention.

Claims

1. An ion sensor comprising a working electrode and a reference electrode, wherein: the working electrode is a processed printed circuit PCB electrode covered with an ion selective membrane, and Au nano-branch Au NBS and a conductive polymer membrane PEDOT are modified on the PCB electrode: PSS.

2. The ion sensor of claim 1, wherein: at least 2 groups of working electrodes and reference electrodes are provided, and different working electrodes are covered with ion selective membranes aiming at different ions.

3. The ion sensor of claim 1, wherein: the ion selective membrane is selected from Na⁺Selective membranes, K⁺Selective Membrane, Ca²⁺Selective film, Mg²⁺Selective membrane, NO₃ ^-Selective membranes and Cl^-At least one of selective membranes.

4. The ion sensor according to any one of claims 1 to 3, wherein: the reference electrode is an Ag/AgCl electrode.

5. A method of manufacturing an ion sensor as claimed in any one of claims 1 to 4, comprising the steps of:

soaking the intermediate electrode A in a mixed solution of 3, 4-ethylenedioxythiophene EDOT and sodium polystyrene sulfonate NaPSS, wherein the intermediate electrode A is a working electrode, and electrodepositing PEDOT: PSS to obtain an intermediate electrode B;

6. The method of claim 5, wherein: the voltage of electro-deposition Au NBS is-0.8V-0.2V; and/or

The cycle number of the electrodeposition of Au NBS is 30-50; and/or

HAuCl₄The concentration of (A) is 0.001-0.005M; and/or

H₂SO₄The concentration of (A) is 0.2-0.8M; and/or

The concentration of EDOT is 0.01-0.05M; and/or

The concentration of NaPSS is 0.1-0.3M; and/or

The electrodeposition time of the middle electrode A is 50-200 s; and/or

The current density of the intermediate electrode A for electrodeposition is 0.5-2.5 mA/cm²。

7. The production method according to claim 5 or 6, characterized in that:

the counter electrode of the electro-deposition Au NBS is a Pt electrode, and the reference electrode is a calomel electrode; and/or

When the intermediate electrode A is subjected to electrodeposition treatment, the counter electrode is a Pt electrode, and the reference electrode is an Ag/AgCl electrode.

8. The method of claim 5, wherein: the reference electrode of the ion sensor is an Ag/AgCl electrode, and is obtained by dripping Ag/AgCl slurry on the surface of a PCB electrode, heating, fixing, drying, dripping a mixed solution containing polyvinyl butyral PVB or polyvinyl chloride PVC, and drying; the mixing ratio of the mixed solution is as follows: 1-3 mL of methanol, 50-90 mg of PVB or PVC, 30-70 mg of NaCl or KCl, 1-5 mg of PEO-PPO-PEO and 0.1-0.5 mg of carbon tubes.

9. The production method according to claim 5, 6 or 8, characterized in that: the ion selective membrane comprises Na⁺Selective membranes, K⁺Selective Membrane, Ca²⁺Selective film, Mg²⁺Selective membrane, NO₃ ^-Selective membranes and Cl^-At least one of selective membranes, wherein:

Na⁺the selective membrane solution comprises the following solutes in percentage by weight: 2-8 mg of a sodium ion carrier, 2-8 mg of sodium tetra-3, 5-bis (trifluoromethylphenyl) borate Na-TFPB, 100-200 mg of PVC and 200-300 mg of diisooctyl sebacate DOS; and/or

K⁺The selective membrane solution comprises the following solutes in percentage by weight: 2-8 mg of valinomycin, 2-8 mg of sodium tetraphenylborate NaTPB, 100-200 mg of PVC and 200-300 mg of DOS; and/or

Ca²⁺The selective membrane solution comprises the following solutes in percentage by weight: 2-8 mg of calcium ion carrier, 2-8 mg of Na-TFPB, 100-200 mg of PVC and 200-300 mg of DOS; and/or

Mg²⁺The selective membrane solution comprises the following solutes in percentage by weight: 2-8 mg of an ionophore, 20-80 mg of o-nitrophenyloctyl ether NOPE, 20-80 mg of PVC and 10-50 mg of p-chlorobenzeneborosylpotassium KTClPB; and/or

NO₃ ^-The selective membrane solution comprises the following solutes in percentage by weight: 2-5 mg of nitric acid ion carrier, 2-5 mg of Na-TFPB, 20-60 mg of PVC and 40-80 mg of DOS; and/or

Cl^-The selective membrane solution comprises the following solutes in percentage by weight: Ag/AgCl paste.

10. A portable ion detector, characterized in that: the ion sensor comprises the ion sensor as claimed in any one of claims 1 to 4, or the ion sensor prepared by the preparation method as claimed in any one of claims 5 to 9.