Detection electrode, electrochemical sensor and use method of electrochemical sensor

Abstract

The present invention relates to the technical field of electrochemical sensors, and provides a detection electrode, an electrochemical sensor and a use method thereof, the detection electrode comprises: a PDMS microfluidic layer comprising a plurality of independent sample introduction channels, inlets of the independent sample introduction channels being used for being connected with an external sample source; the nano porous filter membrane directly faces the PDMS micro-fluidic layer; the electrode array chip layer directly faces the nano porous filter membrane and comprises a plurality of groups of independent electrodes, and the plurality of groups of independent electrodes are in one-to-one correspondence with the plurality of independent sample introduction channels; wherein the PDMS micro-fluidic layer, the nano-porous filter membrane and the electrode array chip layer are sequentially arranged from top to bottom to form a sandwich laminated structure, and the two sides of the nano-porous filter membrane are tightly attached to the outlets of the independent sample introduction channels of the PDMS micro-fluidic layer and the electrode array chip layer. The PDMS micro-channel is adopted for automatic flow guide, accurate conveying and distribution of samples can be achieved, a plurality of independent sample injection channels can be used for treating multiple samples or 12 parallel experiments of the same sample at the same time, cross contamination is reduced, and the detection efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of electrochemical sensor technology, and more specifically, to a detection electrode, an electrochemical sensor, and a method of using the same. Background Technology

[0002] Electrochemical sensors operate by reacting with the gas being measured and generating an electrical signal proportional to the gas concentration. A typical electrochemical sensor consists of a sensing electrode (or working electrode) and a counter electrode, separated by a thin electrolytic layer. Due to their high sensitivity, selectivity, and real-time monitoring capabilities, they are widely used in fields such as industrial safety and environmental monitoring.

[0003] Chinese invention patent application number CN202310123914.6 discloses a detection electrode and an electrochemical sensor. The detection electrode includes a detection substrate, multiple detection cells and detection chambers evenly distributed on the sidewall of the detection substrate, a connecting patch disposed in the detection chamber, a detection electrode assembly with a first end electrically connected to the connecting patch and a second end extending into the detection cell, a protective shell configured to close the detection cell and detection chamber and slidably connected to the detection substrate, a guide plate slidably connected to the detection substrate and capable of extending into the detection cell, and a guide sponge disposed on the guide plate. When the protective shell slides, it pushes the detection electrode assembly to contact the guide sponge.

[0004] The above-mentioned detection electrodes have the following problems: adjacent flow-guiding sponges are physically connected through flow-guiding rings, and there is no isolation between adjacent sponges. Samples may migrate through the sponge fibers, causing crosstalk and posing a risk of sample cross-contamination. Summary of the Invention

[0005] Therefore, in order to solve the problem of sample cross-contamination risk of existing detection electrodes, this invention provides a detection electrode, an electrochemical sensor, and a method of using the same, the specific technical solution of which is as follows:

[0006] A detection electrode comprising:

[0007] The PDMS microfluidic layer includes multiple independent sample inlet channels, the inlets of which are used to connect to an external sample source;

[0008] Nanoporous filter membrane, facing the PDMS microfluidic layer;

[0009] The electrode array chip layer, facing the nanoporous filter membrane, includes multiple sets of independent electrodes, and each set of independent electrodes corresponds to a single independent sample inlet channel.

[0010] The PDMS microfluidic layer, the nanoporous filter membrane, and the electrode array chip layer are arranged sequentially from top to bottom to form a sandwich stacked structure. The two sides of the nanoporous filter membrane are closely attached to the outlet of the independent sample inlet channel of the PDMS microfluidic layer and the electrode array chip layer.

[0011] The detection electrode eliminates mechanical sliding components and utilizes PDMS microchannels for automatic flow guidance, enabling precise sample delivery and distribution. Multiple independent injection channels can simultaneously process multiple samples or up to 12 parallel experiments of the same sample, reducing cross-contamination and improving detection efficiency. Furthermore, by placing a nanoporous filter membrane between the PDMS microfluidic layer and the electrode array chip layer, molecules in the sample can be selectively filtered to remove interfering substances. This ensures that all samples delivered through the independent injection channels pass through the filter membrane, preventing unfiltered samples from directly contacting the electrodes. Working in conjunction with the PDMS microfluidic layer, this effectively improves the accuracy of sample detection.

[0012] Preferably, the inner diameter of the independent sample inlet channel ranges from 50 micrometers to 200 millimeters, and the pore size of the nanoporous filter membrane ranges from 10 nanometers to 100 nanometers.

[0013] Preferably, each group of independent electrodes includes a working electrode, a counter electrode, and a reference electrode, wherein the working electrode is made of Au metal, and the counter electrode and the reference electrode are both made of Pt metal.

[0014] Preferably, the electrode array chip layer is patterned with hydrophilic and hydrophobic properties, the independent injection channels are hydrophilic with a contact angle of less than 30 degrees, and there is a hydrophobic barrier between two adjacent independent injection channels with a contact angle of greater than 110 degrees.

[0015] An electrochemical sensor comprising the aforementioned detection electrode.

[0016] Preferably, the electrochemical sensor further includes a multichannel potentiostat, which is used to apply a square wave voltage to the working electrode.

[0017] Preferably, the electrochemical sensor further includes a temperature compensation module, which is used to acquire the real-time operating temperature of the detection electrode and compensate and correct the detection response current of the working electrode according to the real-time operating temperature.

[0018] A method of using an electrochemical sensor, applied to the electrochemical sensor as described above, includes the following steps:

[0019] The sample to be tested is input into the inlet of an independent sample injection channel. After being filtered by a nanoporous filter membrane, the sample reaches the electrode array chip layer and triggers an electrochemical reaction.

[0020] The detection response current is obtained through an independent electrode, and the concentration of the target molecule in the sample to be tested is obtained based on the detection response current.

[0021] Preferably, obtaining the concentration of the target molecule in the sample to be tested based on the detection response current includes the following steps:

[0022] Obtain the real-time operating temperature of the detection electrode;

[0023] The detection response current is compensated and corrected based on the real-time operating temperature and the preset reference temperature.

[0024] The concentration of the target molecule in the sample to be tested is obtained based on the compensated and corrected detection response current.

[0025] Preferably, obtaining the concentration of the target molecule in the sample to be tested includes the following steps:

[0026] Obtain the Cottrell equation terms used to describe the transient current response of diffusion control under a step potential;

[0027] The number of crosstalk channels, the crosstalk channel current, and the crosstalk coupling coefficient are obtained, and the crosstalk current compensation term is obtained based on the number of crosstalk channels, the crosstalk channel current, and the crosstalk coupling coefficient.

[0028] The concentration of target molecules in the sample to be tested is obtained based on the compensated and corrected detection response current, the Cottrell equation term, and the crosstalk current compensation term. Attached Figure Description

[0029] The invention will be further understood from the following description taken in conjunction with the accompanying drawings. The components in the drawings are not necessarily drawn to scale, but rather the emphasis is on illustrating the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.

[0030] Figure 1 This is a schematic diagram of the overall structure of a detection electrode in one embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the overall process of using an electrochemical sensor according to an embodiment of the present invention;

[0032] Figure 3 This is a flowchart illustrating a specific method for obtaining the concentration of target molecules in a sample to be tested according to an embodiment of the present invention.

[0033] Figure 4 This is a flowchart illustrating a specific method for obtaining the concentration of target molecules in a sample to be tested, according to another embodiment of the present invention.

[0034] Figure 5This is a schematic diagram of the workflow for compensating and correcting the detection response current in one embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the intelligent time-division multiplexing detection process in one embodiment of the present invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. PDMS microfluidic layer, 2. Nanoporous filter membrane, 3. Electrode array chip layer. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0039] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] In this invention, "first" and "second" do not represent a specific quantity or order, but are merely used to distinguish names.

[0042] Before detailing the specific embodiments of the present invention, let's briefly introduce the prior art. Chinese invention patent application number CN202310123914.6, entitled "A Detection Electrode and Electrochemical Sensor," has the following shortcomings:

[0043] 1. Too many components (such as sliding protective shell, guide plate, connecting slot, etc.) require multiple manual sliding operations, which increases the risk of mechanical failure (such as jamming or wear of electrode surface coating).

[0044] 2. Adjacent flow-guiding sponges are physically connected by flow-guiding rings, and there is no isolation between adjacent sponges. Samples may migrate through the sponge fibers, causing crosstalk and posing a risk of sample cross-contamination.

[0045] 3. When the electrode is suspended and fixed in the slot, there is an issue of uneven contact pressure with the flow-guiding sponge, which can easily affect the stability of the current and thus the accuracy of the target molecule concentration detection.

[0046] To reduce the risk of cross-contamination of samples, such as Figure 1 As shown, an embodiment of the present invention provides a detection electrode, which includes a PDMS microfluidic layer 1, a nanoporous filter membrane 2, and an electrode array chip layer 3. The PDMS microfluidic layer includes multiple independent sample injection channels, the inlet of each of the independent sample injection channels being used to connect to an external sample source. The nanoporous filter membrane is directly opposite the PDMS microfluidic layer, and the electrode array chip layer is directly opposite the nanoporous filter membrane. The electrode array chip layer includes multiple sets of independent electrodes, and each set of independent electrodes corresponds one-to-one with one of the multiple independent sample injection channels.

[0047] Specifically, the PDMS microfluidic layer, the nanoporous filter membrane, and the electrode array chip layer are arranged sequentially from top to bottom to form a sandwich stacked structure, with the outlet of the independent sample inlet channel of the PDMS microfluidic layer and the electrode array chip layer tightly attached to both sides of the nanoporous filter membrane.

[0048] Microfluidics refers to the science and technology involved in systems that use microchannels (tens to hundreds of micrometers in size) to process or manipulate tiny fluids (volumes ranging from picoliters to nanoliters). PDMS, or polydimethylsiloxane, is a commonly used flexible material widely applied in microfluidic technology due to its excellent biocompatibility and processability. For example, the PDMS microfluidic layer includes 12 independent sample inlet channels with inner diameters ranging from 50 micrometers to 200 millimeters. The inlets of these channels are connected to an external sample source, and the outlets are directly opposite the middle nanoporous filter membrane. This PDMS microfluidic layer is primarily used to achieve precise sample delivery and distribution. The 12 independent channels can simultaneously process 12 samples (or 12 parallel experiments of the same sample), reducing cross-contamination and improving detection efficiency.

[0049] The nanoporous filter membrane is typically made of polymers (such as polyethersulfone, nitrocellulose) or inorganic nanomaterials (such as alumina), with a pore size ranging from 10 nm to 100 nm and a high porosity (>70%), ensuring efficient passage of small molecules. The pore size of this nanoporous filter membrane can be set according to different sample types. Acting as a "molecular sieve," it can trap large molecular interferences in the sample (such as proteins, cell debris, etc., typically >100 nm in size), allowing only target small molecules (such as metabolites, small molecule drugs, etc.) to pass through, thus improving the specificity of detection in the underlying electrode array chip layer. This nanoporous filter membrane is tightly fitted to the channel outlet of the top PDMS microfluidic layer and the underlying electrode array chip layer, ensuring that all samples delivered through independent injection channels flow through the filter membrane, preventing unfiltered samples from directly contacting the electrodes.

[0050] The substrate of the electrode array chip layer is typically glass or silicon (insulating and flat), and the electrodes are made of Au (gold) / Pt (platinum) bimetallic materials. Each group of independent electrodes includes a working electrode, a counter electrode, and a reference electrode. The working electrode is made of Au metal, while the counter electrode and the reference electrode are both made of Pt metal. Specifically, Au metal has excellent electrical conductivity and its surface can be easily modified with different types of catalysts (such as Pt / Pd bimetallic catalysts and WO3 / ZnO heterojunction catalysts), making it suitable as a working electrode. Pt electrodes have high chemical stability and corrosion resistance, and are commonly used as counter electrodes or reference electrodes. For example, the electrode array chip layer contains 12 sets of independent electrodes, which correspond one-to-one with the 12 independent sample injection channels on the top layer. Each set of independent electrodes includes a working electrode (such as Au), a counter electrode (such as Pt), and a reference electrode (optional). The electrode size is 100-500 μm and the spacing is 50-100 μm. Its main function is to capture the target molecules after filtration through the filter membrane by electrochemical reactions (such as redox reactions) on the electrode surface, and convert the chemical signal into an electrical signal to achieve quantitative detection.

[0051] The top-layer PDMS microfluidic layer features 12 linearly arranged circular inlets, each connected to a microchannel. The channel ends project onto the bottom layer, corresponding one-to-one with the electrodes. The bottom electrode array chip layer contains 12 groups of Au / Pt bimetallic electrodes (each group containing 2-3 electrodes) aligned with the ends of the top-layer microchannels, forming a one-to-one detection unit. The top-layer PDMS microfluidic layer and the middle nanoporous filter membrane are sealed using oxygen plasma treatment or physical compression to ensure no sample leakage. The middle nanoporous filter membrane is in close contact with the bottom electrode array chip layer (without gaps), ensuring the filtered sample reacts directly with the electrode surface, reducing signal loss. The sample is input through an independent inlet channel in the top layer. After flowing through the middle nanoporous filter membrane, large molecules are retained, while small molecules pass through the pores to the bottom electrode array chip layer. These small molecules bind to the specific modification layer on the electrode array surface, triggering an electrochemical reaction. The electrodes detect changes in current / voltage, and signal analysis yields the concentration of the target molecules in the sample.

[0052] As a preferred technical solution, the electrode array chip layer is patterned with hydrophilic and hydrophobic properties. The independent injection channels are hydrophilic with a contact angle of less than 30 degrees. A hydrophobic barrier is formed between two adjacent independent injection channels, and the contact angle of the hydrophobic barrier is greater than 110 degrees, so as to minimize the crosstalk rate between adjacent channels and suppress cross-contamination.

[0053] In summary, the detection electrode, by eliminating mechanical sliding components and employing automatic flow guidance via PDMS microchannels, achieves precise sample delivery and distribution. Multiple independent injection channels can simultaneously process multiple samples or up to 12 parallel experiments of the same sample, reducing cross-contamination and improving detection efficiency. Furthermore, by placing a nanoporous filter membrane between the PDMS microfluidic layer and the electrode array chip layer, molecules in the sample can be selectively filtered, thereby removing interfering substances. This ensures that all samples delivered through the independent injection channels flow through the filter membrane, preventing unfiltered samples from directly contacting the electrode. Working in conjunction with the PDMS microfluidic layer, this effectively improves the accuracy of sample detection.

[0054] An embodiment of the present invention also provides an electrochemical sensor including the aforementioned detection electrode. The electrochemical sensor further includes a multichannel potentiostat for applying a square wave voltage to the working electrode. Exemplarily, the number of channels of the multichannel potentiostat matches the number of independent sample introduction channels in the PDMS microfluidic layer. By applying a stepped scan voltage, such as -0.2V to +0.6V in 0.1V steps, multichannel time-division multiplexing detection is performed, reducing the risk of multichannel electrochemical cross-interference.

[0055] The electrochemical sensor also includes a temperature compensation module, which acquires the real-time operating temperature of the detection electrode and compensates and corrects the detection response current of the working electrode based on the real-time operating temperature. Specifically, the compensation and correction of the detection response current of the working electrode can be based on the Arrhenius correction formula and combined with the real-time operating temperature of the detection electrode to eliminate the influence of environmental fluctuations.

[0056] In summary, the electrochemical sensor of this invention, through its integrated microfluidic layer-electrode design, eliminates mechanical moving parts. Combined with a multi-channel potentiostat for multi-channel time-division multiplexing detection and temperature compensation module, it compensates and corrects the detection response current of the working electrode, achieving breakthrough improvements in detection accuracy, throughput, and reliability. This provides a new generation technology platform for point-of-care testing devices.

[0057] like Figure 2 As shown, one embodiment of the present invention also provides a method for using an electrochemical sensor, applied to the electrochemical sensor as described above, comprising the following steps:

[0058] S1, the sample to be tested is input into the inlet of the independent sample injection channel. The sample to be tested is filtered through a nanoporous filter membrane and then reaches the electrode array chip layer and triggers an electrochemical reaction.

[0059] S2, the detection response current is obtained through an independent electrode, and the concentration of the target molecule in the sample to be tested is obtained based on the detection response current.

[0060] As a preferred technical solution, such as Figure 3 As shown, obtaining the concentration of the target molecule in the sample based on the detection response current includes the following steps:

[0061] S21, Obtain the real-time operating temperature T of the detection electrode. actual .

[0062] S22, based on the real-time operating temperature and the preset reference temperature T ref The detection response current is compensated and corrected.

[0063] Specifically, the detection response current of the working electrode can be compensated and corrected based on the Arrhenius correction formula and the real-time operating temperature of the detection electrode, thus eliminating the influence of environmental fluctuations. For example, according to... The meanings and functions of the variable parameters are shown in the table below:

[0064]

[0065] In the compensation and correction model for the detection response current described above, As an Arrhenius kinetic compensation, it characterizes the effect of temperature on the reaction rate constant. β·(Tactual -T ref As a compensation for non-ideal effects, it compensates for diffusion coefficient shifts caused by changes in solution viscosity, temperature dependence of double-layer capacitance, and phase transition effects at the electrode / electrolyte interface. This detection response current compensation correction model employs a dual compensation mechanism working collaboratively, with the workflow as follows: Figure 5 As shown, the real-time measured detection response current first enters the temperature compensation stage. Temperature compensation is divided into two parallel processing branches: one for exponential term processing (used for reaction kinetic compensation) and the other for linear term processing (used for non-kinetic compensation). Finally, the results of the two branches are combined to obtain the corrected detection response current I. corr The entire process achieves comprehensive correction of the original current by processing different types of temperature compensation terms in parallel, taking into account both the temperature effects on reaction kinetics and physical parameters.

[0066] Based on the above detection response current compensation correction model, a simulation experiment was conducted, and the compensation effect verification data obtained are shown in the table below. In the table, ΔT represents the temperature difference between the real-time operating temperature and the reference temperature.

[0067] Test conditions Uncompensated error Single exponential error compensation Error in this model ΔT = +5℃ +18.7％ +6.2％ +1.3％ ΔT = -8℃ -26.5％ -9.8％ -2.1％ Temperature cycling (10℃-40℃) ±19.3％ ±7.1％ ±1.8％ Gradient temperature field (±3℃) ±8.2％ ±3.5％ ±0.9％

[0068] As can be seen from the table above, compensating and correcting the detection response current based on the above-mentioned detection response current compensation and correction model can effectively reduce the error of the detection response current and improve the accuracy.

[0069] S23, obtain the concentration of target molecules in the sample to be tested based on the compensated and corrected detection response current.

[0070] like Figure 4 As shown, obtaining the concentration of the target molecule in the sample to be tested includes the following steps:

[0071] S24, Obtain the Cottrell equation terms describing the transient current response of diffusion control under a step potential. Specifically, the Cottrell equation terms are expressed as follows: The meanings and functions of the variable parameters are shown in the table below:

[0072]

[0073] In this Cottrell equation, the current and t -1 / 2 It is directly proportional to c, decays over time, and is directly proportional to c, which is the basis for quantitative detection.

[0074] S25, obtain the number of crosstalk channels, the crosstalk channel current, and the crosstalk coupling coefficient, and obtain the crosstalk current compensation term based on the number of crosstalk channels, the crosstalk channel current, and the crosstalk coupling coefficient.

[0075] For example, the crosstalk current compensation term is expressed as The meanings and functions of the variable parameters are shown in the table below:

[0076]

[0077]

[0078] In this crosstalk current compensation term, the crosstalk mechanisms include: 1. Electric field coupling: stray capacitance between adjacent electrodes causes signal leakage; 2. Solution conductivity: electrolyte ion pathways form cross-channel currents; 3. Electromagnetic interference: cross modulation is generated when multiple channels work synchronously.

[0079] S26. Obtain the concentration of target molecules in the sample to be tested based on the compensated and corrected detection response current, the Cottrell equation term, and the crosstalk current compensation term.

[0080] Here, a stepped scanning voltage, such as -0.2V to +0.6V with a step size of 0.1V, can be applied using a multi-channel potentiostat to perform multi-channel time-division multiplexing detection, reducing the risk of multi-channel electrochemical cross-interference. Figure 6 As shown, signal crosstalk interference is resolved through the intelligent time-division multiplexing detection process. First, a square wave voltage is applied, triggering the channel selection process. Then, for the selected channel k, the detection response current I is acquired after a 50ms delay. meas And the detection response current is compensated and corrected to obtain I. corr Then, the compensated and corrected detection response current I corr Crosstalk compensation is performed to obtain the final detection response current I. k Finally, based on the final detected response current I... k The target molecule concentration is calculated, and after all 12 channels have completed the above processing, the results for all 12 channels are output uniformly. This workflow achieves synchronous processing of multi-channel data by reusing single-channel processing logic, and the crosstalk compensation step ensures the independence and accuracy of each channel's measurement. For example, according to the formula... Calculate the concentration of the target molecule.

[0081] Of course, in some embodiments, the target molecule concentration is generally directly proportional to the detection response current. To simplify the calculation, it can be based on the final detection response current I. k (t)=I corr The peak value of (t)-σ(t)I peak Construct a linear function model C = a·I between its concentration and the target molecule concentration. peak +b. Where a and b represent the proportionality coefficient and the constant term, respectively, which can be determined by the least squares fitting method.

[0082] Preferably, for the crosstalk coupling coefficient, based on the formula Calibration is performed. Specifically, the calibration steps include: First, activating only channel j and injecting a known excitation signal current I'. j The second step is to measure the induced current I' in channel k. k Based on the formula Calculate the crosstalk coupling coefficient between channel j and channel k. Where T is the signal integration time, and dt is the time differentiation unit. For the formula... The numerator is the time-domain product of the two signals, representing the signal similarity. The denominator, representing the input signal energy, is mainly used for normalization. Together, they convert the input signal energy into the crosstalk ratio. Here, the formula is used... Adaptively obtaining the crosstalk coupling coefficient between channel j and channel k, instead of using a fixed crosstalk coupling coefficient, can improve the crosstalk suppression capability of multiple channels. In this case, the crosstalk current compensation term is expressed as...

[0083] As a preferred technical solution, to improve dynamic response, the crosstalk current compensation term is expressed as follows: Wherein, β' represents the dynamic response gain coefficient, which can be determined by technicians based on experience, and is generally taken in the range of 0.01-0.5. This represents the rate of change of the target channel current. This can be understood as a dynamic response term, used to compensate for the charging and discharging effects of the electric double layer on the electrode surface and transient disturbances caused by solution eddies. In this function model... In addition, it has a dual-dimensional compensation mechanism to suppress crosstalk coupling between channels and track transient interference, which further improves the crosstalk suppression capability of the multi-channel electrochemical detection system.

[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A detection electrode, characterized in that, The detection electrode includes: The PDMS microfluidic layer includes multiple independent sample inlet channels, the inlets of which are used to connect to an external sample source; Nanoporous filter membrane, facing the PDMS microfluidic layer; The electrode array chip layer, facing the nanoporous filter membrane, includes multiple sets of independent electrodes, and each set of independent electrodes corresponds to a single independent sample inlet channel. The PDMS microfluidic layer, the nanoporous filter membrane, and the electrode array chip layer are arranged sequentially from top to bottom to form a sandwich stacked structure. The two sides of the nanoporous filter membrane are closely attached to the outlet of the independent sample inlet channel of the PDMS microfluidic layer and the electrode array chip layer.

2. The detection electrode as described in claim 1, characterized in that, The inner diameter of the independent sample inlet channel ranges from 50 micrometers to 200 millimeters, and the pore size of the nanoporous filter membrane ranges from 10 nanometers to 100 nanometers.

3. A detection electrode as described in claim 2, characterized in that, Each group of independent electrodes includes a working electrode, a counter electrode, and a reference electrode. The working electrode is made of Au metal, and the counter electrode and the reference electrode are both made of Pt metal.

4. A detection electrode as described in claim 3, characterized in that, The electrode array chip layer is patterned with hydrophilic and hydrophobic properties. The independent injection channels are hydrophilic with a contact angle of less than 30 degrees. There is a hydrophobic barrier between two adjacent independent injection channels, and the contact angle of the hydrophobic barrier is greater than 110 degrees.

5. An electrochemical sensor, characterized in that, Includes the detection electrode as described in any one of claims 1-4.

6. An electrochemical sensor as described in claim 5, characterized in that, The electrochemical sensor also includes a multichannel potentiostat, which is used to apply a square wave voltage to the working electrode.

7. An electrochemical sensor as described in claim 6, characterized in that, The electrochemical sensor also includes a temperature compensation module, which is used to acquire the real-time operating temperature of the detection electrode and compensate and correct the detection response current of the working electrode according to the real-time operating temperature.

8. A method of using an electrochemical sensor, applied to the electrochemical sensor as described in any one of claims 5-7, characterized in that, Includes the following steps: The sample to be tested is input into the inlet of an independent sample injection channel. After being filtered by a nanoporous filter membrane, the sample reaches the electrode array chip layer and triggers an electrochemical reaction. The detection response current is obtained through an independent electrode, and the concentration of the target molecule in the sample to be tested is obtained based on the detection response current.

9. The method of using an electrochemical sensor as described in claim 8, characterized in that, The steps to obtain the concentration of target molecules in the sample based on the detection response current are as follows: Obtain the real-time operating temperature of the detection electrode; The detection response current is compensated and corrected based on the real-time operating temperature and the preset reference temperature. The concentration of the target molecule in the sample to be tested is obtained based on the compensated and corrected detection response current.

10. A method of using an electrochemical sensor as described in claim 9, characterized in that, Obtaining the concentration of the target molecule in the sample to be tested includes the following steps: Obtain the Cottrell equation terms used to describe the transient current response of diffusion control under a step potential; The number of crosstalk channels, the crosstalk channel current, and the crosstalk coupling coefficient are obtained, and the crosstalk current compensation term is obtained based on the number of crosstalk channels, the crosstalk channel current, and the crosstalk coupling coefficient. The concentration of target molecules in the sample to be tested is obtained based on the compensated and corrected detection response current, the Cottrell equation term, and the crosstalk current compensation term.

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