CN105021682B - A kind of needle-like chlorion sensor and preparation method thereof - Google Patents

Abstract

The invention discloses a needle-shaped chloride ion sensor, which comprises a reference electrode and a selective electrode, wherein the selective electrode comprises a silver wire and a silver chloride layer coated on one end of the silver wire; the reference electrode comprises A metal wire, a solid electrolyte layer and a reference film coated on one end surface of the metal wire in sequence. The needle-shaped chlorine ion sensor aims at the shortcomings of the traditional chlorine ion concentration detection, such as large volume, long time consumption, and inability to detect trace amounts. The chlorine ion selective electrode and the external reference electrode are made into a needle shape and integrated into one body, which can quickly detect Microorganisms, trace blood, etc., and it is easy to carry and easy to operate.

Description

A needle-shaped chloride ion sensor and its preparation method

technical field

The invention relates to the technical field of electrochemical sensors, in particular to a needle-like chloride ion sensor and a preparation method thereof.

Background technique

Chloride ion is an ion that widely exists in nature and is the most abundant anion in living organisms. In the human body, chloride ions, together with sodium ions and other cations, maintain the volume and osmotic pressure of extracellular fluid, and help maintain the acid-base balance of body fluids. At the same time, it helps transport carbon dioxide in the body to the lungs for excretion. What's more worth mentioning is that chloride ions also participate in the formation of gastric acid in the human body, promote the absorption of vitamin B12 and iron, and can also promote the decomposition of starch and food digestion by activating salivary amylase. Chloride ions can also stimulate liver function, promote the discharge of metabolic waste in the liver, and even stabilize the membrane potential of nerve cells.

Chloride ion is an indispensable ion for the human body. People generally obtain chloride ion through diet. The main source of chloride ion is sodium chloride, and a small amount comes from potassium chloride. The most common salt, soy sauce and other condiments contain a lot of chlorine. Irrational meals, or those who sweat a lot, have severe diarrhea, vomiting, or need to use diuretics for medical treatment, and those who suffer from severe dehydration in the body may have different degrees of chlorine deficiency. Chlorine deficiency will break the electrolyte balance in the human body, and it is often accompanied by sodium deficiency. In severe cases, it can cause hypochloremic metabolic alkalosis, which can easily lead to insufficient gastric acid, poor digestion and absorption, and aggravate hair loss, tooth loss, and even poor muscle contraction. growth and development. Therefore, it is also necessary to detect chloride ions in living organisms.

The ion-selective electrode is a kind of indicator electrode that is selective for a specific ion, and the chloride ion-selective electrode is a special electrode that uses electrochemical principles to detect the concentration of chloride ions in a solution. The detection of chloride ions has a wide range of applications in the fields of medicine, chemical industry, pharmacy, environmental protection and food, especially the detection of chloride ions in human body fluids has important medical and clinical significance. Most of the current chloride ion sensors are used in industrial sites. Patent 201310274636 discloses a chloride ion sensor using an all-fiber sensing mode. The measurement process is relatively complicated, and it is impossible to quickly and conveniently measure the chloride ion content in a trace solution.

Contents of the invention

The invention provides a needle-shaped chlorine ion sensor and a preparation method thereof. The needle-shaped chlorine ion sensor has a fast detection speed and can realize trace detection.

A needle-shaped chloride ion sensor, comprising a reference electrode and a selective electrode, wherein the selective electrode comprises a silver wire and a silver chloride layer coated on one end of the silver wire;

The reference electrode includes a metal wire, a solid electrolyte layer and a reference film coated on one end surface of the metal wire in sequence.

Aiming at the disadvantages of the traditional chloride ion concentration detection, such as large volume, long time-consuming, and inability to detect trace amounts, the present invention adopts Ag/AgCl as the chloride ion selective electrode, and makes the chloride ion selective electrode and the reference electrode into needle-shaped And integrated, it can quickly detect microorganisms, trace blood, etc., with good detection performance and less interference.

Preferably, the silver wire and the metal wire have a diameter of 0.1-0.6 mm and a length of 4-5 cm. The size is easy to carry.

One end of the selective electrode coated with the silver chloride layer is the detection end, the other end is the output end, and the middle part between the detection end and the output end is coated with an insulating layer;

One end of the reference electrode coated with a solid electrolyte layer and a reference film is a detection end, and the other end is an output end, and the middle part between the detection end and the output end is covered with an insulating layer.

A casing is also provided outside the insulating layer, and the insulating layer protrudes from both ends of the casing.

The present invention also provides a kind of preparation method of described needle-shaped chloride ion sensor, comprises the following steps:

(1) one end of the silver wire and the metal wire is treated with aluminum oxide suspension, sulfuric acid solution, deionized water and surfactant aqueous solution successively;

Among them, when the alumina suspension is processed, it is polished by ultrasonic vibration for 10 to 15 minutes;

The concentration of the sulfuric acid solution is 0.5-2mol/L, and the silver wire and metal wire are soaked for 3-5 minutes during treatment;

(2) the silver wire treated in step (1) is chlorinated by an electrochemical method in a solution containing chloride ions, and dried in the dark;

(3) Disperse the conductive polymer in deionized water to prepare a suspension, then add a treatment agent and sodium carboxymethylcellulose or sodium hydroxyethylcellulose to prepare an electrolyte slurry, and dip the metal wire several times Electrolyte slurry, so that the electrolyte slurry is coated on the surface of the metal wire to form a solid electrolyte layer, and dry in the dark;

The volume percent concentration of the conductive polymer in the suspension is 1-5%;

The mass percent concentration of the treatment agent in the electrolyte slurry is 0.01-0.1%;

The mass percent concentration of the sodium carboxymethylcellulose or sodium hydroxyethylcellulose in the electrolyte slurry is 1.5% to 5%;

(4) Dissolving plasticizer, lipophilic macromolecules, and non-conductive high molecular polymers in cyclohexanone or tetrahydrofuran is prepared as a reference membrane solution, and the metal wire treated in step (3) is dipped in the reference membrane solution several times. For the comparison membrane solution, control the solid electrolyte layer not to be completely submerged by the reference membrane solution when dipping in the reference membrane solution, and the reference membrane solution is coated on the outside of the solid electrolyte layer to form a reference film, which is protected from light and dried;

Based on the total mass of the solute, the mass percentage of the plasticizer is 60.7-65.9%, the mass percentage of the lipophilic macromolecule is 0.1-0.6%, and the mass percentage of the non-conductive polymer is 32.8-36.4%;

(5) The heat-shrinkable tube is respectively coated on the middle and upper parts of the chloride ion selective electrode and the reference electrode, as an insulating layer;

(6) Connect and fix the working electrode and the reference electrode with a shell to obtain the needle-shaped chloride ion sensor.

The metal wire is gold wire, silver wire, platinum wire or copper wire.

In step (1), the concentration of the alumina suspension is 60-100g/L, and the diameter of the alumina powder for preparing the suspension is 0.5 microns to 50 nanometers;

The aqueous surfactant solution is 0.1-1% sodium carboxymethyl cellulose solution or sodium hydroxyethyl cellulose solution.

In step (2), the solution containing chloride ions is an aqueous solution of 0.1-1 mol/liter of sodium chloride, potassium chloride, calcium chloride or magnesium chloride.

The electrochemical method is cyclic voltammetry or constant voltage method.

In step (3), the conductive polymer is selected from polypyrrole and its derivatives, polyaniline and its derivatives, or polythiophene and its derivatives;

The treatment agent is polyethylene glycol p-isooctyl phenyl ether.

In step (4), the non-conductive polymer is selected from polyvinyl chloride or polyurethane;

The lipophilic macromolecule is selected from sodium tetraphenylborate, tetrakis(4-chlorophenyl) borate chloride and tetrakis[3,5-bis(trifluoromethyl)phenyl]potassium borate;

Described plasticizer is selected from two (2-ethylhexyl) adipic acid, 2-nitrophenyl octyl ether, phthalate, dioctyl adipate, dioctyl sebacate or hexyl Propylene glycol diacid.

The concentration of the non-conductive polymer in the solvent in the reference membrane solution is 72.6-140.0 mg/mL.

In the actual measurement, the lower end of the chloride ion selective electrode and the external reference electrode in the all-solid-state chloride ion sensor is immersed in the chloride ion solution to be measured, and the upper end of the metal wire is connected with the peripheral detection circuit to detect the chlorine ion in the solution. Chloride concentration.

In the present invention, the chloride ion selective electrode is a silver/silver chloride electrode, which is usually used as a reference electrode, especially in the case of a liquid electrode, the inner filling liquid is selected to be saturated potassium chloride, which is a common commercial reference electrode . Chloride ions and silver chloride in the solution form a dynamic equilibrium. When the concentration of the solution changes, the potential of the silver/silver chloride electrode changes accordingly, which conforms to the Nernst equation. The reference electrode is stable in the solution, and the potential difference between the two can be measured to calculate the concentration of chloride ions in the solution.

Since the present invention is an all-solid-state sensor, it does not need to carry bulky liquid electrodes, and the detection is convenient and fast. Moreover, the sensor is very miniaturized and can detect a small volume of chloride ion to be tested, such as the detection of microbial chloride ions or the detection of blood chloride ions in clinical medicine. Multiple sensors can also be arranged side by side to form a sensor array for multi-channel measurement.

Description of drawings

Fig. 1 is the structural representation of needle-like chloride ion sensor of the present invention;

Fig. 2 is the structural representation of the chloride ion selective electrode of the needle-shaped chloride ion sensor shown in Fig. 1;

Fig. 3 is the structural representation of the reference electrode of needle-like chloride ion sensor shown in Fig. 1;

Fig. 4 is the response curve of the voltage of the needle-shaped chloride ion sensor that the embodiment of the present invention 1 obtains to concentration;

FIG. 5 is a response curve of voltage to concentration of the needle-shaped chloride ion sensor obtained in Example 2 of the present invention.

detailed description

It can be seen from the structural diagram of the needle-shaped chloride ion sensor shown in FIG. 1 that the needle-shaped chloride ion sensor includes a chloride ion selective electrode, a reference electrode, an insulating layer 6 and a casing 7 .

It can be seen from the structural diagram of the chloride ion selective electrode shown in FIG. 2 that the chloride ion selective electrode includes a silver wire 1 and a silver chloride layer 2 , wherein the silver chloride layer 2 covers the lower half of the silver wire 1 .

As can be seen from the reference electrode shown in Figure 3, the reference electrode comprises a metal wire 3, a solid electrolyte layer 4 and a reference film 5, wherein the solid electrolyte layer 4 is coated on the lower half of the metal wire 3, and the reference film 5 is coated on the surface of the solid electrolyte layer, and the upper end of the solid electrolyte layer 4 is not covered by the reference film 5 . The insulating layer 6 is coated on the outside of the chloride ion selective electrode and the reference electrode, and the shell 7 is outside the insulating layer 6 and is slightly smaller than the insulating layer 6, so that the chloride ion electrode and the reference electrode are fixed and parallel to each other.

Example 1

(1) Select two silver wires with a diameter of 0.5mm and a length of 5cm, marked as 1 and 2 respectively; prepare a 70g/L alumina suspension, put the silver wire into the alumina suspension, and use ultrasonic Oscillate and polish for 10 minutes; then soak the silver wire in 0.8mol/L dilute sulfuric acid solution for 3 minutes, and rinse with deionized water;

(2) Clean the silver wire with 0.3% sodium carboxymethyl cellulose aqueous solution;

(3) Put the treated silver wire 1 in a 250mmol/L sodium chloride solution using a constant voltage method with a voltage of 0.22V for 30 seconds. Chlorinate the silver wire and dry it away from light;

(4) Take PEDOT/PSS [poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid]: water = 1:99 mass ratio to prepare a mixed solution, add 0.05% of the total mass of the mixed solution polyethylene glycol Alcohol p-isooctyl phenyl ether, and then add 3% sodium carboxymethylcellulose to prepare electrolyte slurry; dip silver wire 2 for several times to get electrolyte slurry, make it coated on the surface of silver wire, and form a solid state Electrolyte layer;

(5) Dissolve 166uL 2-nitrophenyloctyl ether, 1.425mg tetrakis (4-chlorophenyl) potassium borate, and 103.74mg polyvinyl chloride in 1mL tetrahydrofuran to prepare a viscous solution as a reference membrane solution; ) The treated silver wire 2 dipped the reference membrane liquid several times, making it coated on the outside of the solid electrolyte layer, and slightly lower than the solid electrolyte layer, and kept away from light and dried;

(6) The heat-shrinkable tube is respectively coated on the upper end of the working electrode and the reference electrode to obtain a needle-shaped chloride ion selective electrode and a corresponding reference electrode;

(7) Connect the working electrode and the reference electrode with a casing and fix them in parallel to obtain a needle-shaped chloride ion sensor.

Using the needle-shaped chloride ion sensor prepared in this implementation example to measure chloride ion solutions with different concentrations, the response curve of voltage to concentration is obtained, and the results are shown in Figure 4.

Example 2

(1) Select a silver wire and a platinum wire with a diameter of 0.5mm and a length of 5cm, prepare a 70g/L alumina suspension, use ultrasonic vibration to polish for 10 minutes, and soak in 0.8mol/L dilute sulfuric acid solution for 3 minutes, rinse with deionized water;

(2) Clean silver wire and platinum wire with 0.3% sodium carboxymethyl cellulose;

(3) Apply cyclic voltammetry to the treated silver wire in a solution containing chloride ions, the voltage is from -1 to 1V, the scan rate is 0.1V/s, and the number of scan segments is 12, the silver wire is chlorinated and protected from light dry;

(4) Take PEDOT/PSS: water = 1:99 mass ratio to prepare a mixed solution, add 0.05% polyethylene glycol p-isooctyl phenyl ether, and then add 3% sodium carboxymethyl cellulose to prepare Electrolyte slurry; the platinum wire is dipped in the electrolyte slurry several times to coat the surface of the platinum wire to form a solid electrolyte layer;

(5) Dissolve 189uL dioctyl sebacate, 1.425mg sodium tetraphenylborate, and 103.74mg polyvinyl chloride in 1mL cyclohexanone to prepare a viscous solution as a reference membrane solution; The platinum wire is dipped in the reference membrane solution several times, so that it is coated on the outside of the solid electrolyte layer and slightly lower than the solid electrolyte layer, and is protected from light and dried;

(6) The heat-shrinkable tube is respectively coated on the upper end of the working electrode and the reference electrode to obtain a needle-shaped chloride ion selective electrode and a corresponding reference electrode;

(7) Connect the working electrode and the reference electrode with a casing and fix them in parallel to obtain a needle-shaped chloride ion sensor.

Using the needle-shaped chloride ion sensor prepared in this implementation example to measure chloride ion solutions with different concentrations, the response curve of voltage to concentration was obtained, and the results are shown in FIG. 5 .

Claims (7)

1. a needle-shaped chloride ion sensor, comprising reference electrode and selective electrode, is characterized in that, described selective electrode comprises silver wire and is coated on the silver chloride layer of silver wire one end; The reference electrode includes a metal wire and a solid electrolyte layer and a reference film coated on the surface of one end of the metal wire in sequence; Its preparation method comprises the following steps: (1) one end of the silver wire and the metal wire is treated with aluminum oxide suspension, sulfuric acid solution, deionized water and surfactant aqueous solution successively; (2) The silver wire treated in step (1) is chlorinated by cyclic voltammetry or constant voltage method in an aqueous solution of 0.1 to 1 mol/liter of sodium chloride, potassium chloride, calcium chloride or magnesium chloride. chemical, avoid light and dry; (3) Disperse the conductive polymer in deionized water to prepare a suspension, then add a treatment agent and sodium carboxymethylcellulose or sodium hydroxyethylcellulose to prepare an electrolyte slurry, and dip the metal wire several times Electrolyte slurry, so that the electrolyte slurry is coated on the surface of the metal wire to form a solid electrolyte layer, and dry in the dark; (4) Dissolving plasticizer, lipophilic macromolecules, and non-conductive high molecular polymers in cyclohexanone or tetrahydrofuran is prepared as a reference membrane solution, and the metal wire treated in step (3) is dipped in the reference membrane solution several times. For the comparison membrane solution, control the solid electrolyte layer not to be completely submerged by the reference membrane solution when dipping in the reference membrane solution, and the reference membrane solution is coated on the outside of the solid electrolyte layer to form a reference film, which is protected from light and dried; (5) The heat-shrinkable tube is respectively coated on the middle and upper parts of the chloride ion selective electrode and the reference electrode, as an insulating layer; (6) Connect and fix the selective electrode and the reference electrode with a shell to obtain the needle-shaped chloride ion sensor. 2. needle-shaped chloride ion sensor according to claim 1, is characterized in that, described selective electrode is coated with one end of silver chloride layer and is detection end, and the other end is output end, and the connection between detection end and output end The middle part is covered with an insulating layer; One end of the reference electrode coated with a solid electrolyte layer and a reference film is a detection end, and the other end is an output end, and the middle part between the detection end and the output end is covered with an insulating layer. 3 . The needle-shaped chloride ion sensor according to claim 2 , wherein a casing is provided outside the insulating layer, and the insulating layer protrudes from both ends of the casing. 4 . 4. needle-shaped chloride ion sensor according to claim 1, is characterized in that, in step (1), described aluminum oxide suspension concentration is 60-100g/L, and the aluminum oxide of preparation described suspension is The powder diameter is 0.5 micron to 50 nanometers; The aqueous surfactant solution is 0.1-1% sodium carboxymethyl cellulose solution or sodium hydroxyethyl cellulose solution. 5. needle-shaped chloride ion sensor according to claim 1, is characterized in that, in step (3), described conductive polymer is selected from polypyrrole and derivative thereof, polyaniline and derivative thereof or polythiophene and derivative thereof. its derivatives; The treatment agent is polyethylene glycol p-isooctyl phenyl ether. 6. needle-shaped chloride ion sensor according to claim 1, is characterized in that, in step (4), described non-conductive polymer is selected from polyvinyl chloride or polyurethane; The lipophilic macromolecule is selected from sodium tetraphenylborate, chlorine tetrakis (4-chlorophenyl) borate or potassium tetrakis [3,5-bis (trifluoromethyl) phenyl] borate; Described plasticizer is selected from two (2-ethylhexyl) adipic acid, 2-nitrophenyl octyl ether, phthalate, dioctyl adipate, dioctyl sebacate or hexyl Propylene glycol diacid. 7. The needle-shaped chloride ion sensor according to claim 6, characterized in that the concentration of the non-conductive polymer in the solvent in the reference membrane solution is 72.6-140.0 mg/mL.