Screen-printed electrode system for detecting ethyl carbamate

Abstract

The utility model belongs to the technical field of food detection, and in particular relates to a screen-printed electrode system for detecting ethyl carbamate, which comprises an electrode substrate and a screen-printed electrode, the electrode substrate is of an integrated structure made of polyethylene glycol terephthalate; the counter electrode is a platinum electrode, is printed on the left side of the electrode substrate through platinum paste, and is in a 1 / 2 circular ring shape; the reference electrode is an Ag / AgCl electrode and is printed on the right side of the electrode substrate by silver / silver chloride ink; the working electrode is composed of a carbon ink layer and a reaction layer; the insulating layer is an insulating ink layer; and the electrode wires are printed by silver / silver chloride ink and are arranged below the electrode substrate in parallel. Electrochemical detection is carried out through an innovative screen-printed electrode system, the detection process is simplified, the cost is reduced, the electrode system is plug-and-play and free of maintenance, and independent detection without electrolyte pollution can be achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of food detection, and particularly relates to a screen-printed electrode system for detecting ethyl carbamate. Background Art

[0002] Ethyl carbamate (EC) is a genotoxic carcinogen present in fermented foods and alcoholic beverages, posing a significant health risk. Traditional detection methods, such as gas chromatography-mass spectrometry (GC-MS), multidimensional gas chromatography-mass spectrometry (MDGC-MS), high-performance liquid chromatography-fluorescence detection (HPLC-FLD), ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS), etc., require complex procedures and expensive equipment, limiting the demand for rapid on-site detection. Therefore, there is an urgent need to develop a real-time, rapid, and accurate means for detecting EC.

[0003] In modern analytical chemistry and sensing technologies, electrochemical sensors are widely used in environmental monitoring, food safety, biomedicine, and other fields due to their advantages of high sensitivity, rapid response, and simple operation. As a key component of electrochemical sensors, the selection and design of electrodes directly affect the performance of the sensors. Traditional electrode materials and manufacturing processes are usually complex, costly, and difficult to mass-produce, limiting the widespread application of electrochemical sensors. In recent years, screen-printed electrodes have become an electrode material that has received much attention due to their advantages of low cost, easy fabrication, miniaturization, and high customization.

[0004] Most existing methods for detecting ethyl carbamate (EC), such as gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography-mass spectrometry (HPLC-MS), although having high precision and sensitivity, their complex sample pretreatment steps and high equipment costs make them difficult to be applied in rapid on-site detection. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a screen-printed electrode system for detecting ethyl carbamate, which has high stability and sensitivity, low cost, and simple operation, and solves the deficiencies of the existing technology in the rapid on-site detection of ethyl carbamate.

[0006] To achieve the above purpose, the utility model adopts the following technical scheme: A screen-printed electrode system for detecting ethyl carbamate, the electrode system includes:

[0007] An electrode substrate, the electrode substrate is an integrated structure made of polyethylene terephthalate, the thickness of the electrode substrate is 0.25 mm, the length is 35 mm, and the width is 15 mm;

[0008] Counter electrode, the counter electrode is a platinum electrode, printed on the left side of the electrode substrate with platinum paste, in a semi-circular ring shape, with an outer diameter of the ring being 8 mm and an inner diameter being 5 mm;

[0009] Reference electrode, the reference electrode is an Ag / AgCl electrode, printed on the right side of the electrode substrate with silver / silver chloride ink, in a 1 / 6 circular ring shape, with an outer diameter of the ring being 8 mm and an inner diameter being 5 mm;

[0010] Working electrode, the working electrode is composed of a carbon ink layer and a reaction layer, with a diameter of 3.5 mm;

[0011] Insulating layer, the insulating layer is an insulating ink layer, 15 mm wide and 18 mm long.

[0012] Electrode lead, the electrode lead is printed with silver / silver chloride ink, arranged in parallel below the electrode substrate, in a slender strip shape, with a width of 1.5 mm and a length of 15 mm.

[0013] Preferably, the working electrode further includes: a reaction layer, and the reaction layer contains a specific molecular recognition element for detecting ethyl carbamate.

[0014] Preferably, the specific molecular recognition element is a molecularly imprinted polymer based on lanthanum manganate and graphene oxide composite (LaMnO3@GO@MIP), and the molecularly imprinted polymer contains specific recognition sites for ethyl carbamate.

[0015] Preferably, the molecularly imprinted polymer is coated onto the LaMnO3@GO composite material by precipitation polymerization.

[0016] Preferably, an electrode exposure position is provided on the insulating layer for exposing the electrode during measurement.

[0017] Technical effects and advantages of the present utility model: A screen-printed electrode system for detecting ethyl carbamate proposed by the present utility model has the following advantages compared with the prior art:

[0018] The present utility model performs electrochemical detection through an innovative screen-printed electrode system, simplifies the detection process, reduces costs, the electrode system is plug-and-play and maintenance-free, and can achieve independent detection without electrolyte contamination. It successfully solves the bottleneck of the existing ethyl carbamate detection technology in on-site applications. The provided detection system has high stability and sensitivity, greatly enhancing the feasibility and reliability of on-site rapid detection while ensuring the detection quality. Brief Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the screen-printed electrode system for detecting ethyl carbamate of the present utility model.

[0020] In the figure: 1. Electrode substrate; 2. Counter electrode; 3. Reference electrode; 4. Working electrode; 5. Insulating layer; 6. Electrode wire. Specific embodiments

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] The present invention provides a Figure 1 screen-printed electrode system for detecting ethyl carbamate as shown. The electrode system includes: an electrode substrate 1, a counter electrode 2, a reference electrode 3, a working electrode 4, an insulating layer 5, and an electrode wire 6.

[0023] In this embodiment, the parameters of the electrode substrate 1 are as follows:

[0024] Substrate material: The electrode substrate selects polyethylene terephthalate (PET) as the material. PET is a thermoplastic polyester with excellent mechanical properties, creep resistance, fatigue resistance, abrasion resistance, and dimensional stability. It has good electrical insulation properties and is less affected by temperature. In addition, PET also has good folding resistance, oil resistance, fat resistance, dilute acid resistance, dilute alkali resistance, and resistance to most solvents. This material also has excellent high and low temperature resistance and can be used for a long time within a temperature range of 120°C. It can even withstand a high temperature of up to 150°C for short-term use and maintain its mechanical properties at a low temperature of -70°C. The PET material is non-toxic, odorless, and has high hygienic safety, making it suitable for manufacturing screen-printed electrodes.

[0025] Substrate size: The thickness of the electrode substrate is 0.25 mm, the length is 35 mm, and the width is 15 mm. This size design takes into account both the actual use requirements of the electrode and is convenient for production and operation.

[0026] Substrate function: The main function of the electrode substrate is to fix the counter electrode, reference electrode, and working electrode, providing a stable support platform for these electrodes. At the same time, the substrate also needs to have a certain flatness to facilitate the production and use of the electrodes.

[0027] Substrate characteristics: The PET substrate is not only heat-resistant but also has good flatness, which is particularly important for the production of screen-printed electrodes because a substrate with good flatness can improve the quality and consistency of the electrodes.

[0028] In summary, as a high-performance substrate material, PET can not only meet the requirements of electrode production but also ensure the stability and reliability of the electrodes. By selecting the appropriate substrate size and material, the overall performance of the electrodes can be effectively improved, making them suitable for on-site rapid detection of ethyl carbamate application scenarios.

[0029] In this embodiment, the parameters of electrode 2 are as follows:

[0030] Electrode material: The counter electrode uses platinum (Pt) as the material. Platinum is a noble metal with good electrical conductivity and chemical stability, not easily corroded, and exhibits excellent catalytic performance in electrochemical reactions.

[0031] Electrode shape and position: The counter electrode is in a semi-circular ring shape and is located on the left side of the electrode substrate. This design enables the counter electrode to maximize contact with the electrolyte solution in a limited space, thereby improving the transfer efficiency of electrochemical signals.

[0032] Size specifications: The outer diameter of the circular ring of the counter electrode is 8 mm, and the inner diameter is 5 mm. Such a size design not only ensures sufficient surface area for good current transmission but also facilitates cooperation with other electrode components.

[0033] Preparation method: The counter electrode is fabricated by screen-printing technology to print platinum paste at the designated position on the electrode substrate. First, the platinum paste is evenly applied to a special screen, and then through pressure, the paste is transferred through the screen to the electrode substrate to form the required pattern. After that, through steps such as drying and sintering, the platinum paste is solidified into a firm electrode.

[0034] Electrode function: The main function of the counter electrode is to provide a stable current loop during electrochemical testing to ensure accurate measurement of electrochemical signals. It participates in the electrochemical reaction process together with the working electrode to assist in the transfer of electrons.

[0035] Electrode characteristics: Due to its good electrical conductivity and chemical stability, the platinum electrode can effectively reduce the overpotential in electrochemical reactions and improve the sensitivity and accuracy of electrochemical detection.

[0036] From the above description, it can be seen that by selecting the electrode material, designing the shape, and optimizing the preparation method, the performance of the electrochemical sensor can be effectively improved, making it more suitable for on-site rapid detection of ethyl carbamate application scenarios.

[0037] In this embodiment, the parameters of the reference electrode 3 are as follows;

[0038] Electrode material: The reference electrode uses Ag / AgCl (silver / silver chloride) as the material. Ag / AgCl is a commonly used reference electrode material with good electrochemical stability and reproducibility, and can maintain a stable potential output for a long time.

[0039] Electrode shape and position: The reference electrode is in the shape of a 1 / 6 circular ring and is located on the right side of the electrode substrate. This design helps to reduce the mutual interference between electrodes and is also beneficial to the spatial layout between electrodes.

[0040] Size specification: The outer diameter of the circular ring of the reference electrode is 8 mm, and the inner diameter is 5 mm. Such a size design can ensure that the reference electrode has sufficient surface area to provide a stable reference potential.

[0041] Preparation method: The reference electrode is prepared by screen-printing the silver / silver chloride ink on the designated position of the electrode substrate. First, the silver / silver chloride ink is evenly applied on a special screen, and then the ink is transferred through the screen to the electrode substrate under pressure to form the required pattern. After that, through steps such as drying and sintering, the silver / silver chloride ink is cured into a firm electrode.

[0042] Electrode function: The role of the reference electrode is to provide a stable reference potential during the electrochemical test to ensure the accurate measurement of electrochemical signals. It does not directly participate in the electrochemical reaction, but together with the working electrode and the counter electrode, it maintains the potential balance of the electrochemical system.

[0043] Electrode characteristics: Due to its stable potential output and good chemical stability, the Ag / AgCl electrode can effectively reduce the influence of external factors on electrochemical signals and improve the accuracy and reliability of electrochemical detection.

[0044] From the above description, it can be seen that by selecting the material of the reference electrode, designing the shape, and optimizing the preparation method, the overall performance of the electrochemical sensor can be significantly improved, making it more suitable for the application scenario of rapid on-site detection of ethyl carbamate.

[0045] In this embodiment, the parameters of the working electrode 4 are as follows:

[0046] Electrode structure: The working electrode consists of a carbon ink layer and a reaction layer. Among them, the carbon ink layer provides good conductivity and a large surface area; the reaction layer contains specific molecular recognition elements for detecting ethyl carbamate.

[0047] Electrode size: The diameter of the working electrode is 3.5 mm. Such a size design can ensure that the working electrode has sufficient surface area to improve the response speed and sensitivity of electrochemical signals.

[0048] Carbon ink layer: The carbon ink layer is a mixture composed of carbon powder and binder. It is evenly coated on the electrode substrate through screen printing technology to form a uniform and dense conductive layer. The thickness and density of the carbon ink layer need to be strictly controlled to ensure good conductivity and a high specific surface area.

[0049] Reaction layer: The reaction layer contains a specific molecular recognition element - a molecularly imprinted polymer (LaMnO3@GO@MIP) based on the composite of lanthanum manganite and graphene oxide. Molecularly Imprinted Polymers (MIPs) are a type of synthetic material with specific molecular recognition functions. These molecularly imprinted polymers are designed for the specific structure of ethyl carbamate. They are prepared by copolymerizing the template molecule and functional monomers under appropriate conditions. After the target molecule and functional monomers form a specific spatial structure, the target molecule is removed. It can specifically recognize and bind to the target molecule, thus achieving the effective detection of ethyl carbamate.

[0050] Specific molecular recognition element: The molecularly imprinted polymer is coated onto the LaMnO3@GO composite material by precipitation polymerization.

[0051] By designing the structure and composition of the working electrode, the detection sensitivity and selectivity of the electrochemical sensor for ethyl carbamate can be significantly improved, making it suitable for on-site rapid detection application scenarios.

[0052] In this embodiment, the parameters of the insulating layer 5 are as follows:

[0053] Insulating material: The insulating layer uses insulating ink as the material. Insulating ink is a special type of ink with good insulating properties. It can form a uniform insulating layer on the electrode substrate to isolate each electrode and prevent short circuits between them.

[0054] Insulating layer size: The width of the insulating layer is 15 mm and the length is 18 mm. This size design ensures sufficient coverage area to effectively isolate each electrode, while leaving enough space for the exposure of the electrodes.

[0055] Preparation method: The insulating layer is formed by evenly coating the insulating ink on the electrode substrate through screen printing technology. Except for the electrode areas that need to be exposed, the rest are covered by the insulating layer. Then, through drying and curing processes, the insulating ink forms a firm insulating layer.

[0056] Electrode exposure positions: There are electrode exposure positions on the insulating layer. These positions are usually pre-processed by methods such as laser cutting or mechanical drilling for electrode exposure during measurement. This can ensure direct contact between the electrodes and the electrolyte solution to achieve electrochemical reactions.

[0057] Exposure Site Design: The design of the electrode exposure site needs to consider the size and position of the electrode. For example, the diameter of the exposure site of the working electrode is 3.5 mm, which matches the diameter of the working electrode to ensure that the electrode is fully exposed to the electrolyte solution. The exposure sites of the counter electrode and the reference electrode are designed according to their respective sizes.

[0058] Functions and Characteristics: The main function of the insulating layer is to isolate each electrode to prevent short circuits between them, and at the same time ensure the correct setting of the electrode exposure site to achieve accurate measurement of electrochemical signals. The use of insulating ink can also improve the durability and stability of the electrode.

[0059] By selecting the insulating material, designing the size of the insulating layer, and setting the electrode exposure site, the overall performance of the electrochemical sensor can be effectively improved, making it more suitable for the application scenario of rapid on-site detection of ethyl carbamate.

[0060] In this embodiment, the parameters of the electrode wire 6 are as follows:

[0061] Electrode Wire Material: The electrode wire is made of silver / silver chloride (Ag / AgCl) ink. The Ag / AgCl material can provide a stable potential, enabling the electrode wire to have a low resistance and good current conduction ability when transmitting signals.

[0062] Electrode Wire Shape and Position: The electrode wire is in the shape of a slender strip and is arranged parallel to the lower side of the electrode substrate. Such a design helps to reduce the resistance in the signal transmission path and can ensure the stable and reliable connection of each electrode.

[0063] Size Specification: The width of the electrode wire is 1.5 mm and the length is 15 mm. Such a size design can not only ensure sufficient conduction paths but also take into account the mechanical strength and flexibility of the electrode wire.

[0064] Preparation Method: The electrode wire is printed on the designated position of the electrode substrate by screen printing technology using silver / silver chloride ink. First, the silver / silver chloride ink is evenly applied on a special screen, and then pressure is applied to make the ink transfer through the screen to the electrode substrate to form the required wire pattern. After that, through steps such as drying and sintering, the silver / silver chloride ink is cured into a firm and stable wire.

[0065] Function of Electrode Wire: The main function of the electrode wire is to effectively connect each electrode to the electrochemical workstation during the electrochemical test process to ensure the accurate transmission of electrochemical signals. Through stable conductivity, the electrode wire can ensure low-loss transmission of signals, thereby improving the detection accuracy of the overall sensor.

[0066] Electrode wire characteristics: The silver / silver chloride material has excellent electrochemical stability and corrosion resistance, and can maintain its performance in various complex electrochemical environments. In addition, the Ag / AgCl wire also has low resistance and good current conduction ability, which helps to reduce the transmission loss of electrochemical signals and ensure the stability and accuracy of test results.

[0067] By selecting appropriate wire materials, designing the shape and size of the electrode wire, and optimizing its preparation method, the performance of the electrochemical sensor can be effectively improved, making it more suitable for the application scenario of rapid on-site detection of ethyl carbamate.

[0068] On the other hand, the preparation process of the above reaction layer is as follows:

[0069] Synthesis of LaMnO3@GO material: Dissolve 2.8 mmol of lanthanum nitrate and 2.8 mmol of manganese nitrate in an aqueous solution. After stirring with a magnetic stirrer at a constant temperature of 40 °C for 30 min, add 5.6 mmol of citric acid and continue stirring at 60 °C for 120 min. Add 0.168 g of GO powder, then ultrasonically disperse for 1 h. Put the formed clear sol into an oven at 105 °C to gradually form a brownish-yellow xerogel. After the sample is dried, raise the oven temperature to 180 °C and keep it for 30 min. At this time, the xerogel undergoes spontaneous combustion, and then a loose black substance is formed.

[0070] Grind the obtained black sample and put it into a muffle furnace. Calcine it in the muffle furnace at 500 °C for 2 h, and then raise the temperature of the muffle furnace to 800 °C and calcine for 4 h. Cool the sample to room temperature and grind it to obtain powdered LaMnO3@GO.

[0071] Synthesis of LaMnO3@GO@MIP: Disperse EC (0.05 mmol) in 5 mL of methanol, and then add MAA (0.3 mmol) to the mixture under continuous stirring with nitrogen. After stirring for 30 minutes, slowly mix EGDMA (0.5 mmol) and AIBN (20 mg) in a stirrer, and then add 50 mg of LaMnO3@GO and vigorously oscillate in a 60 °C water bath for 24 h. After drying and grinding, a gray solid powder is obtained.

[0072] Use the Soxhlet extraction method to wash with methanol for 36 h to remove the template molecules from the molecularly imprinted polymer on LaMnO3@GO. When EC is not detected in the washing solution by GC-MS method, the washing is completed. Finally, dry to obtain LaMnO3@GO@MIP.

[0073] The reaction layer is obtained by coating a mixed solution (6 μL) of LaMnO3@GO@MIP nanomaterials with a mass concentration of 20 mg / mL on the surface of a carbon electrode and drying it with an infrared lamp.

[0074] Usage method: Insert the reaction area of the screen-printed electrode (including the working electrode, reference electrode, and auxiliary electrode) into the solution to be measured, or drop the solution to be measured on the surface of the reaction area of the screen-printed electrode.

[0075] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, 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 screen-printed electrode system for detecting ethyl carbamate, characterized in that, The electrode system includes: An electrode substrate, which is an integrated structure made of polyethylene terephthalate. The thickness of the electrode substrate is 0.25 mm, the length is 35 mm, and the width is 15 mm. A counter electrode, which is a platinum electrode printed on the left side of the electrode substrate with platinum paste, in a 1 / 2 circular ring shape, with an outer diameter of the circular ring of 8 mm and an inner diameter of 5 mm. A reference electrode, which is an Ag / AgCl electrode printed on the right side of the electrode substrate with silver / silver chloride ink, in a 1 / 6 circular ring shape, with an outer diameter of the circular ring of 8 mm and an inner diameter of 5 mm. A working electrode, which is composed of a carbon ink layer and a reaction layer, with a diameter of 3.5 mm. An insulating layer, which is an insulating ink layer, with a width of 15 mm and a length of 18 mm. Electrode leads, which are printed with silver / silver chloride ink and arranged in parallel below the electrode substrate.

2. The screen-printed electrode system for detecting ethyl carbamate according to claim 1, characterized in that The working electrode further includes: A reaction layer, which contains a specific molecular recognition element for detecting ethyl carbamate.

3. The screen-printed electrode system for detecting ethyl carbamate according to claim 2, characterized in that, The specific molecular recognition element is a molecularly imprinted polymer based on a lanthanum manganite and graphene oxide composite material, and the molecularly imprinted polymer contains specific recognition sites for ethyl carbamate.

4. A screen-printed electrode system for detecting ethyl carbamate according to claim 3, characterized in that, The molecularly imprinted polymer is coated onto the LaMnO3@GO composite material by precipitation polymerization.

5. A screen-printed electrode system for detecting ethyl carbamate according to claim 1, characterized in that An electrode exposure position is provided on the insulating layer for exposing the electrode during measurement.

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