CN-122016959-A - Double-cavity heterogeneous micro-electrolysis cell based on theta-type glass tube and preparation method thereof

CN122016959ACN 122016959 ACN122016959 ACN 122016959ACN-122016959-A

Abstract

The invention relates to a double-cavity heterogeneous micro-electrolysis cell based on a theta-type glass tube and a preparation method thereof, wherein the double-cavity heterogeneous micro-electrolysis cell is prepared by a unique double-wire packaging-selective dissolving process, and specifically comprises the steps of drawing the middle parts of the theta-type glass tubes with metal wires respectively arranged in two cavities by a laser drawing instrument to obtain two independent theta-type glass tubes with tips respectively; the method comprises the steps of conducting hydrophobization treatment on the outer wall of the tip of one theta-type glass tube, then selectively dissolving one metal wire to enable a cavity of the tip to form a micro-channel, and conducting electrode assembly after polishing to obtain the double-cavity heterogeneous micro-electrolytic cell. The process is characterized in that a three-electrode system is perfectly integrated in a small theta-shaped tip through a solid electrode cavity/hollow channel cavity heterostructure created by selective dissolution, the structure is compact, and the analysis of a trace amount of samples can be realized. Solves the problems of difficult integration and unstable interface of the traditional micro-electrolytic cell, and is suitable for high-sensitivity detection of micro-samples.

Inventors

WANG WEI
LIU CHENG
Huo Wenyue
Kou meng

Assignees

井冈山大学

Dates

Publication Date: 20260512
Application Date: 20260128

Claims (9)

1. A preparation method of a double-cavity heterogeneous micro-electrolysis cell based on a theta-type glass tube is characterized by comprising the following steps: The method comprises the steps of S1, double-wire packaging, namely respectively inserting a first metal wire and a second metal wire into the middle parts of two independent chambers of a theta-type glass tube, wherein the diameters of the first metal wire and the second metal wire are in a micron level, and performing heat sealing and drawing on the middle part of the theta-type glass tube by using a laser drawing instrument to form a thinnest structure in the middle part of the theta-type glass tube and stretch-break the thinnest structure from the thinnest part so as to obtain two independent theta-type glass tubes respectively provided with a tip, wherein the first metal wire and the second metal wire are respectively packaged in the closed end of the tip of each theta-type glass tube; S1a, outer wall hydrophobic treatment, namely performing hydrophobic treatment on the outer wall of the tip of the theta-type glass tube obtained in the step S1; S2, selectively dissolving the metal wire in one cavity of the theta-glass tube obtained in the step S1a, namely the second metal wire, so that a micro-channel is formed in the cavity of the tip, and the first metal wire in the other cavity is reserved and used as a working electrode; S3, end face polishing, namely performing grinding and polishing treatment on the tip end of the theta-shaped glass tube obtained in the step S2, so that the outlet of the micro-channel, the end face of the reserved first metal wire chamber and the end face of the middle glass partition wall are positioned on the same plane; And S4, electrode assembly, namely, injecting electrolyte into a chamber where the micro-channel is located, then inserting a counter electrode and a reference electrode, inserting a third metal wire into the chamber which is packaged with the first metal wire, so that the third metal wire is in contact conduction with the first metal wire sealed before, namely, assembling the electrolyte, the counter electrode, the reference electrode, the working electrode and the third metal wire into the theta-type glass tube obtained in the step S3 to form the double-cavity heterogeneous micro-electrolytic cell.
2. The method according to claim 1, wherein the hydrophobizing treatment is a silylation treatment.
3. The preparation method according to claim 2, characterized in that: the silanization reagent used in the silanization treatment is one or a mixture of more of octadecyltriethoxysilane, dodecyl triethoxysilane, hexamethyldisilazane, octadecyltrichlorosilane and dimethyldichlorosilane.
4. The method of producing a glass tube according to claim 1, wherein the step S2 of selectively dissolving the second wire which is the wire in one of the chambers of the glass tube obtained in the step S1a is performed by immersing the tip of the glass tube obtained in the step S1a in an etchant to selectively dissolve the second wire, wherein the first wire and the second wire are metals having different chemical activities, the etchant is a solution capable of specifically dissolving the second wire without corroding the glass and the first wire, or the etchant is injected into the chamber in which the second wire is enclosed to dissolve the second wire, and the first wire and the second wire are metals having the same or different chemical activities.
5. The method according to claim 4, wherein the first wire is one of a platinum wire, a gold wire, a silver wire, a copper wire or a nickel wire; The etching solution is a mixed solution formed by mixing deionized water, hydrochloric acid and hydrogen peroxide, and the preparation method of the etching solution comprises the steps of mixing 50 mL deionized water with 37 wt% hydrochloric acid with 20 mL% concentration and 30 wt% hydrogen peroxide with 10 mL% concentration to prepare the etching solution; or the etching solution is 50% nitric acid solution.
6. The method according to claim 1, wherein in step S4, the counter electrode and the reference electrode are the same silver wire or silver wires treated by chlorination, namely Ag/AgCl wires.
7. The method of claim 1, wherein the third wire is one of a nickel wire and a copper wire.
8. The double-cavity heterogeneous micro-electrolysis cell prepared by the preparation method according to any one of claims 1-7 is characterized by comprising a theta-shaped glass tube (1) body, wherein the theta-shaped glass tube (1) body is divided into a first cavity and a second cavity by an intermediate glass partition wall (2), and the bottom end of the theta-shaped glass tube (1) body is conical and is a heterogeneous closed end; The bottom end of the first cavity is packaged with a first metal wire (3), the upper end of the first metal wire (3) is connected with a third metal wire (10), and the third metal wire (10) extends out of the first cavity and is used for being connected with an external circuit through a wire, wherein the diameter of the first metal wire (3) is in a micro-scale or nano-scale; The bottom end of the second chamber is provided with an open micro-channel (11), the aperture of the micro-channel (11) is 10-500 mu m, and the second chamber is injected with electrolyte and is inserted with a counter electrode and a reference electrode; The lower end face of the first chamber, the outlet of the micro-channel (11) and the end face of the middle glass partition wall (2) are positioned on the same plane.
9. The double-cavity heterogeneous micro-electrolytic cell according to claim 8, wherein the counter electrode and the reference electrode inserted into the micro-channel (11) of the second cavity are Ag wires or Ag/AgCl wires (12), the Ag wires or the Ag/AgCl wires (12) serve as the counter electrode and the reference electrode at the same time, the diameter of the Ag wires or the Ag/AgCl wires is 10-500 μm when being matched with the aperture of the micro-channel (11), the first metal wires (3) are one of platinum wires, gold wires, silver wires, copper wires or nickel wires, the diameter of the first metal wires (3) is 0.01-500 μm, and the third metal wires (10) are one of nickel wires or copper wires.

Description

Double-cavity heterogeneous micro-electrolysis cell based on theta-type glass tube and preparation method thereof Technical Field The invention belongs to the field of electrochemical sensing and micro-area electrochemistry, and particularly relates to a double-cavity heterogeneous micro-electrolysis cell based on a theta-type glass tube and a preparation method thereof. Background The micro-electrolytic cell has important application in the fields of bioelectrochemical sensing, local electrochemical impedance spectroscopy, micro-area corrosion research and the like. The traditional electrolytic cell has larger volume and large consumption of electrolyte, and is difficult to meet the requirement of high-spatial resolution electrochemical measurement on micrometer/nanometer scale areas or trace samples (such as single cells and micro liquid drops). In pursuit of miniaturization, some solutions have been proposed in the prior art, but all have limitations to different degrees. For example, a complex microelectromechanical system (MEMS) process is used to integrate a three-electrode system on a chip, which, although capable of achieving miniaturization, has the problems of complicated process, high cost, difficulty in accurately controlling the electrode/solution interface, and the like, and the signals between the different electrodes may cause cross interference. To simplify the process, researchers have turned to a structure using θ -type glass capillaries. One such concept (e.g., CN116626128 a) is to deposit platinum nanoparticles at the capillary unilateral channel tip by a long-term (12-24 hours) liquid phase interface reaction to build a mini-cell for hydroxyl radical generation. The scheme has long preparation period, high specific function (limited by free radical generation), and the double chambers are all of channel structures, and are not optimized to form the most stable electrode-liquid path interface. Another idea (such as CN 112305038B) is to integrate the working electrode (such as platinum iridium oxide) and the reference electrode (such as Ag/AgCl) into the double cavities of the θ -type glass tube through the steps of filling, packaging, and the like, so as to make a composite electrode for pH detection. The method has a plurality of process steps (involving welding, drawing, gel filling and the like), and is essentially formed into a symmetrical structure of a double solid electrode, so that the method is difficult to be conveniently transformed into a universal sensing platform in which a working electrode and an independent electrolyte/counter electrode channel are heterogeneous integrated. In summary, the current micro-electrolytic cell technology faces a common dilemma that the structure is simple, the preparation is convenient and fast, the cost is low, the performance is stable, the functions are universal, and the interface is controllable while the miniaturization is pursued. Either limited by complex and expensive micromachining processes or sacrificed structural optimization or functional versatility due to simplified processes. Therefore, there is a strong need in the art for a new design and preparation method of a micro-electrolytic cell, which can directly construct a miniaturized device that is capable of isolating the working electrode and the electrolyte path of the integrated counter/reference electrode from each other in space, has stable interface, and is suitable for various electrochemical detection by a simple and reliable process. Disclosure of Invention The invention provides a double-cavity heterogeneous micro-electrolytic cell and a preparation method thereof, wherein the double-cavity heterogeneous micro-electrolytic cell is simple in preparation method and can realize physical isolation of a working electrode and a counter/reference electrode, and the preparation method is based on a theta-type glass tube. The invention aims at realizing the following technical scheme that the invention firstly protects a preparation method, and the core of the preparation method is double-wire packaging-selective dissolution, in particular to a preparation method of a double-cavity heterogeneous micro-electrolytic cell based on a theta-type glass tube, which comprises the following steps: And S1, double-wire packaging, namely respectively inserting a first metal wire and a second metal wire into the middle parts of two independent chambers of the theta-shaped glass tube, wherein the diameters of the first metal wire and the second metal wire are in a micron level, heating, sealing and drawing the middle part of the theta-shaped glass tube by using a laser drawing instrument to form a thinnest structure in the middle part of the theta-shaped glass tube, and breaking the thinnest structure by pulling the thinnest structure, so that two independent theta-shaped glass tubes with tips are obtained, wherein the first metal wire and the second metal wire are respectively packaged in