Novel high-performance ethylene glycol sensor and preparation method thereof

Abstract

The invention discloses a novel high-performance ethylene glycol sensor and a preparation method thereof, the novel high-performance ethylene glycol sensor comprises a microfluidic chip substrate, a working electrode and a reference electrode, and the electrode end of the working electrode is provided with a nano material modification layer; a micro-channel is formed in the upper surface of the micro-flow control chip substrate, and a liquid inlet and a liquid outlet are formed in the two ends of the micro-channel respectively; the working electrode and the reference electrode are embedded in the upper surface of the micro-flow control chip substrate, and the electrode ends of the reference electrode and the working electrode extend to the side wall position of the micro-flow channel and are sequentially arranged at intervals in the flow direction of the micro-flow channel. The micro-flow control chip substrate serves as a basic carrier of the sensor, the micro-channel is arranged on the surface of the micro-flow control chip substrate, the working electrode and the reference electrode are arranged in specific areas of the inner wall of the micro-channel respectively, the ethylene glycol concentration is detected through potential difference, complex sample pretreatment is not needed, and the detection accuracy is high. The ethylene glycol solution in the micro-channel can be directly detected, and automatic detection and real-time online monitoring can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of sensors, in particular to a novel high-performance ethylene glycol sensor and a preparation method thereof. Background Art

[0002] Ethylene glycol is an important chemical raw material, widely used in many industrial fields such as polyester fiber, antifreeze, lubricants, etc. However, ethylene glycol is toxic to a certain extent, and accidental ingestion or excessive exposure may cause serious damage to human health, such as kidney failure. In the fields of environmental monitoring, chemical production process monitoring, and food and beverage industry, accurate detection of ethylene glycol content is extremely important.

[0003] In the prior art, the invention disclosure patent with patent number CN202410334426.4 discloses a method for determining organic additives in ethylene glycol coolant using high performance liquid chromatography, which includes: 1) preparation of standard solution; 2) sample preparation, diluting the sample with ethylene glycol aqueous solution to obtain the sample solution to be tested; 3) liquid chromatography conditions, using 0.5% phosphoric acid-acetonitrile as the mobile phase for equal strength elution, octadecyl chromatographic column for separation, and diode array detector for detection; 4) content calculation. The organic additives in ethylene glycol coolant can be perfectly separated and quantitatively analyzed within 15 minutes.

[0004] The above patent provides a method for detecting ethylene glycol by liquid chromatography. The method has good repeatability, high accuracy, and simple operation. It is suitable for the rapid detection of organic additives in ethylene glycol coolants, and provides technical support for ensuring the quality safety and life monitoring of ethylene glycol coolants during use. However, when ethylene glycol is detected by liquid chromatography, the initial sample preparation is complicated, the operation is cumbersome, the analysis time is long, and the purity requirements for sample cleaning are high, which makes it impossible to achieve automated detection and it is difficult to achieve real-time online monitoring functions. Further improvement is needed. Summary of the invention

[0005] The purpose of the present invention is to provide a new high-performance ethylene glycol sensor and a preparation method thereof, aiming to improve the existing ethylene glycol detection method which is to detect by liquid chromatography, which has the problems of complex sample preparation, cumbersome operation, long analysis time and high purity requirement for sample cleaning, resulting in the inability to realize automated detection and difficulty in realizing real-time online monitoring function.

[0006] The present invention is implemented as follows: a new type of high-performance ethylene glycol sensor includes a microfluidic control chip substrate, a working electrode and a reference electrode, the electrode end of the working electrode is provided with a nano material modification layer; a microchannel is opened on the upper surface of the microfluidic control chip substrate, and a liquid inlet and a liquid outlet are respectively provided at both ends of the microchannel; the working electrode and the reference electrode are both embedded on the upper surface of the microfluidic control chip substrate, the electrode ends of the reference electrode and the working electrode are both extended to the side wall position of the microchannel, and are arranged in sequence and spaced along the flow direction of the microchannel.

[0007] Preferably, the microfluidic control chip substrate is a basic carrier of the sensor, and is made of a material with good mechanical strength, high thermal conductivity and high chemical stability.

[0008] Preferably, the nanomaterial modification layer is made of materials such as carbon nanotubes, metal oxide nanoparticles and conductive polymer nanofibers.

[0009] Preferably, the working electrode is made of a material with high chemical stability and good conductivity, and sensitive and stable response to ethylene glycol molecules.

[0010] According to the second aspect of the present invention, a novel high-performance ethylene glycol sensor preparation method is provided. The specific steps of the novel high-performance ethylene glycol sensor preparation method are as follows:

[0011] S100, forming a microchannel structure on the surface of the substrate by using micromachining technology;

[0012] S200, making a working electrode and a reference electrode in a preset area of ​​the inner wall;

[0013] S300, dropping carbon nanotubes, metal tube oxide nanoparticles or conductive polymer dispersion onto the surface of the working electrode;

[0014] S400, heating and drying under appropriate conditions to form a nano-modified layer;

[0015] S500, sealing the chip and other post-processing processes are performed and connected to the external circuit system.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention sets a microfluidic control chip substrate as the basic carrier of the sensor, sets a microchannel on its surface, and sets a working electrode and a reference electrode in specific areas of the inner wall of the microchannel respectively. The concentration of ethylene glycol is detected by the potential difference between the two. No complicated sample pretreatment is required, and the ethylene glycol solution flowing through the microchannel can be directly detected. It is simple and convenient, and can be automatically detected and monitored online in real time.

[0018] 2. The present invention greatly reduces the space occupied by the device by using a microfluidic control chip substrate, which is beneficial to improving detection sensitivity, reducing pollution risks and sample consumption. The working electrode is modified by using a nanomaterial functional coating, which can not only significantly enhance the selective recognition and detection capabilities of ethylene glycol, but also give the sensor excellent performance such as rapid response and long-term stability. The overall volume is small and the integration is high, which is convenient for miniaturization and intelligent detection. Detection is carried out through the working electrode and the reference electrode, so that the sensor has high detection sensitivity, fast response speed, strong selective recognition ability, and good anti-interference performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0020] Figure 2 The present invention Figure 1 The structural diagram at A in the middle;

[0021] Figure 3 It is a schematic diagram of the process structure of the preparation of the present invention.

[0022] In the figure: 1. Microfluidic control chip substrate; 2. Microfluidic channel; 3. Liquid inlet; 4. Liquid outlet; 5. Working electrode; 6. Reference electrode; 7. Nanomaterial modification layer. DETAILED DESCRIPTION

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] The following is a further description with reference to the accompanying drawings and specific embodiments:

[0025] Example 1

[0026] like Figure 1 and Figure 2As shown, a new type of high-performance ethylene glycol sensor includes a microfluidic control chip substrate 1, which is the basic carrier of the sensor and uses materials with good mechanical strength, high thermal conductivity and high chemical stability. The microfluidic control chip substrate 1 using a silicon substrate greatly reduces the space occupied by the device, which is conducive to improving the detection sensitivity, reducing the risk of contamination and sample consumption. It also includes a working electrode 5 and a reference electrode 6. The working electrode 5 uses a material with high chemical stability and good conductivity, and is sensitive and stable to ethylene glycol molecules. The electrode end of the working electrode 5 is provided with a nanomaterial modification layer 7; the nanomaterial modification layer 7 is selectively coated on the surface of the working electrode 5, giving the working electrode 5 a high affinity to enrich and catalyze the target analyte. The nanomaterial modification layer 7 uses materials such as carbon nanotubes, metal oxide nanoparticles and conductive polymer nanofibers. The type of material of the nanomaterial modification layer 7 is not limited to a certain type, and can be flexibly selected according to actual needs. Commonly used materials include carbon nanotubes, metal oxide nanoparticles, conductive polymer nanofibers, etc. Different materials have their own advantages and can be used alone or in combination as needed. The surface of the working electrode 5 can be coated with single-walled carbon nanotubes or multi-walled carbon nanotubes. The excellent electron transport performance and large specific surface area of ​​carbon nanotubes can significantly increase the enrichment and catalytic ability of electroactive substances on the working electrode 5. It is also possible to choose to coat transition metal oxide nanoparticles such as tin oxide, cerium oxide, and manganese oxide. The nanoparticles are assembled into a porous structure to form electrochemical active sites and mass transfer channels to promote the electron transport and interfacial reaction of the target analyte. In addition, conductive polymer materials such as polypyrrole, polyaniline, and polythiophene can also be used to grow nanofiber membranes in situ on the surface of the working electrode by electrochemical oxidation polymerization. This type of porous membrane structure is not only conducive to the enrichment, separation, and identification of analytes, but its hydrophilicity and hydrophobicity can also be regulated by surface modification. Different nanomaterials have complementary functional advantages. The materials can be reasonably selected and compositely modified according to needs to further optimize the performance of the sensor.

[0027] like Figure 1 and Figure 2As shown, a microchannel 2 is provided on the upper surface of the microfluidic control chip substrate 1, and the microchannel 2 is processed and prepared on the microfluidic control chip substrate 1 by photolithography and wet etching processes. A liquid inlet 3 and a liquid outlet 4 are respectively provided at both ends of the microfluidic control chip 2; the sample solution flows through the microfluidic channel for detection. The working electrode 5 and the reference electrode 6 are both embedded on the upper surface of the microfluidic control chip substrate 1, and the gold solution is dripped into the preset area in the microfluidic channel 2 and heat-treated to make the reference electrode 6 and the working electrode 5. The single-walled carbon nanotubes are dispersed in N,N-dimethylformamide solution, ultrasonically dispersed for 30 minutes to form a stable dispersion, dripped on the surface of the working electrode 5 and dried at 80°C for 2 hours to make the working electrode 5 with a nanomaterial modified layer 7. The electrode ends of the reference electrode 6 and the working electrode 5 are both extended to the side wall position of the microfluidic channel 2, and are arranged in sequence along the flow direction of the microfluidic channel 2. The working electrode and the reference electrode are respectively arranged in specific areas of the inner wall of the microchannel, and the potential difference between the two is related to the concentration of the analyte.

[0028] Example 2

[0029] like Figure 1 and Figure 2As shown, a new type of high-performance ethylene glycol sensor includes a microfluidic control chip substrate 1, which is the basic carrier of the sensor and is made of materials with good mechanical strength, high thermal conductivity and high chemical stability. It also includes a working electrode 5 and a reference electrode 6. The working electrode 5 is made of materials with high chemical stability and good conductivity, and sensitive and stable response to ethylene glycol molecules. The electrode end of the working electrode 5 is provided with a nanomaterial modification layer 7; the nanomaterial modification layer 7 is made of materials such as carbon nanotubes, metal oxide nanoparticles and conductive polymer nanofibers. A microchannel 2 is provided on the upper surface of the microfluidic control chip substrate 1, and a liquid inlet 3 and a liquid outlet 4 are respectively provided at both ends of the microfluidic channel 2; the working electrode 5 and the reference electrode 6 are both embedded on the upper surface of the microfluidic control chip substrate 1, and the microfluidic control chip substrate 1 is a polydimethylsiloxane (PDMS) microfluidic chip. The polydimethylsiloxane (PDMS) microfluidic chip is prepared by injection molding. Platinum wire is placed in a preset area, and it is encapsulated with a PDMS substrate during hot pressing to obtain a reference electrode 6 and a working electrode 5. Tin oxide sol dispersion is dripped onto the surface of the working electrode 5, and heated at 120°C for 2 hours to form a tin oxide nanomaterial modification layer 7. Secondly, a microchannel 2 structure can also be made on a glass substrate by ultraviolet photolithography. Gold solution is dripped onto the preset area and heat-treated to form gold electrodes as the working electrode 5 and the reference electrode 6. The polypyrrole monomer solution is electrochemically oxidized and polymerized in the presence of ferric chloride to prepare a polypyrrole nanomaterial modification layer 7 covering the working electrode 5. The electrode ends of the reference electrode 6 and the working electrode 5 are both extended to the side wall of the microchannel 2, and are arranged in sequence along the flow direction of the microchannel 2. The working electrode and the reference electrode are respectively arranged in specific areas of the inner wall of the microchannel, and the potential difference between the two is related to the concentration of the substance to be measured.

[0030] Example 3

[0031] like Figure 3 As shown, according to the second aspect of the present invention, a novel high-performance ethylene glycol sensor preparation method is provided, and the specific steps of the novel high-performance ethylene glycol sensor preparation method are as follows:

[0032] S100, forming a microchannel structure on the surface of the substrate by using micromachining technology;

[0033] S200, making a working electrode and a reference electrode in a preset area of ​​the inner wall;

[0034] S300, dropping carbon nanotubes, metal tube oxide nanoparticles or conductive polymer dispersion onto the surface of the working electrode;

[0035] S400, heating and drying under appropriate conditions to form a nano-modified layer;

[0036] S500, sealing the chip and other post-processing processes are performed and connected to the external circuit system.

[0037] In summary, the present invention uses a microfluidic control chip substrate 1 as the basic carrier of the sensor, a microchannel 2 is arranged on its surface, and a working electrode 5 and a reference electrode 6 are respectively arranged in specific areas of the inner wall of the microchannel 2. The concentration of ethylene glycol is detected by the potential difference between the two. No complicated sample pretreatment is required, and the ethylene glycol solution flowing through the microchannel 2 can be directly detected. It is simple and convenient, and can be automatically detected and monitored online in real time. By using the microfluidic control chip substrate 1, the space occupied by the device is greatly reduced, which is conducive to improving the detection sensitivity, reducing the risk of pollution and sample consumption. The working electrode is modified by a functional coating of nanomaterials, which can not only significantly enhance the selective recognition and detection ability of ethylene glycol, but also give the sensor excellent performance such as fast response and long-term stability. The overall volume is small and the integration is high, which is convenient for miniaturization and intelligent detection. Moreover, detection is performed through the working electrode 5 and the reference electrode 6, so that the sensor has high detection sensitivity, fast response speed, strong selective recognition ability, and good anti-interference performance.

[0038] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A novel high-performance ethylene glycol sensor, comprising a microfluidic control chip substrate (1), characterized in that: The invention also comprises a working electrode (5) and a reference electrode (6), wherein the electrode end of the working electrode (5) is provided with a nano material modification layer (7); a microfluidic channel (2) is provided on the upper surface of the microfluidic control chip substrate (1), and a liquid inlet (3) and a liquid outlet (4) are provided at two ends of the microfluidic channel (2); the working electrode (5) and the reference electrode (6) are both embedded in the upper surface of the microfluidic control chip substrate (1), and the electrode ends of the reference electrode (6) and the working electrode (5) are both extended to the side wall of the microfluidic channel (2), and are sequentially spaced along the flow direction of the microfluidic channel (2).

2. A novel high performance ethylene glycol sensor according to claim 1, characterized in that: The microfluidic control chip substrate (1) is a basic carrier of the sensor and is made of a material with good mechanical strength, high thermal conductivity and high chemical stability.

3. A novel high performance ethylene glycol sensor according to claim 1, characterized in that: The nano material modification layer (7) is made of materials such as carbon nano tubes, metal oxide nano particles and conductive polymer nano fibers.

4. A novel high performance ethylene glycol sensor according to claim 1, characterized in that: The working electrode (5) is made of a material with high chemical stability and good electrical conductivity, and sensitive and stable response to ethylene glycol molecules.

5. A method for preparing a novel high-performance ethylene glycol sensor, used to prepare the novel high-performance ethylene glycol sensor as claimed in claim 1, characterized in that: The specific steps are as follows: S100, forming a microchannel structure on the surface of the substrate by using micromachining technology; S200, making a working electrode and a reference electrode in a preset area of ​​the inner wall; S300, dropping carbon nanotubes, metal tube oxide nanoparticles or conductive polymer dispersion onto the surface of the working electrode; S400, heating and drying under appropriate conditions to form a nano-modified layer; S500, sealing the chip and other post-processing processes are performed and connected to the external circuit system.

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