An electrochemical detection system with HCT correction function and detection method thereof

Abstract

The invention discloses an electrochemical detection system with HCT correction function, comprising: an electrochemical sensor, a main control module, an HCT resistance acquisition module, a double-pole double-throw switch switching module, a constant potential circuit module, a three-electrode current acquisition module, a temperature acquisition module and a display module; the electrochemical sensor is provided with a three-electrode system including a reference electrode, an auxiliary electrode and a working electrode; the HCT resistance acquisition module measures the resistance of a blood sample based on the reference electrode and the auxiliary electrode, and determines the current HCT value of the blood sample through the linear relationship between HCT and the resistance of the blood sample; the double-pole double-throw switch switching circuit is connected or disconnected with the three-electrode system of the electrochemical sensor; the constant potential circuit module, the three-electrode current acquisition module and the main control module form a three-electrode data acquisition circuit; the display module is used to display the excitation voltage, the current HCT value of the blood sample, the current signal, the temperature value, the time information and the accurate lactate concentration measurement value. A corresponding detection method is also disclosed.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical detection, and in particular to an electrochemical detection system with HCT correction function and a detection method thereof. Background Art

[0002] Hematocrit (HCT) refers to the ratio of the volume of red blood cells in the blood, or the percentage of red blood cells in the whole blood. On average, the hematocrit of adults is usually between 35% and 45%, while the hematocrit of pregnant women, newborns and smokers can reach 60% or higher, and people with anemia or other diseases can be 30% or lower. Traditional electrochemical detection methods are often interfered by hematocrit when testing analytes in blood samples. Taking blood lactate as an example, when the hematocrit of blood is too low, the measured current is too large, resulting in a high blood lactate value; on the contrary, when the hematocrit in the blood is too high, the measured current may be too small, resulting in a low blood lactate value. Therefore, an electrochemical detection system with HCT compensation is particularly important for eliminating the influence of hematocrit and thus improving the accuracy of such products.

[0003] The prior art is to add a pair of separate HCT electrodes to the sensor in addition to the current test electrode, so as to achieve the measurement of HCT. For example, CN202010110722.8 discloses a hematocrit correction method and a biosensor test device, in which the electrochemical biosensor determines the hematocrit of blood by the current value corresponding to the hemoglobin concentration of the blood, or determines the hematocrit of blood by the red blood cell impedance phase angle tanφ of the blood. Then the correction is performed by the measured analyte concentration correction equation to calculate the corrected concentration value of the final analyte. This method is simple and easy to implement, has few interfering factors, accurate testing, can effectively eliminate the influence of hematocrit on the determination of analyte concentration, and improves the accuracy and sensitivity of the results. However, adding an additional pair of electrodes to the sensor will make the sensor manufacturing process more complicated, the number of electrodes on the sensor will increase, and more blood samples will be required to fill the electrode cavity; using two channels, the manufacturing process is complicated compared with the prior art, and more samples are required, the sampling amount is increased, and the user's use pain is deepened. Summary of the invention

[0004] The purpose of the present invention is to provide an electrochemical detection system with HCT correction function and a detection method thereof. The detection system is based on a traditional three-electrode electrochemical sensor. Through a double-pole double-throw switch switching circuit, the auxiliary electrode and the reference electrode on the electrochemical sensor are connected in sequence to measure the resistance of the blood sample. The current HCT in the blood is converted through the linear relationship between HCT and the resistance of the blood sample; then, the three-electrode system (working electrode, auxiliary electrode and reference electrode) on the electrochemical sensor is connected through circuit switching to measure the lactate current in the blood sample; finally, the calibration equation related to the HCT value and the analyte concentration is used to calibrate the electrochemical sensor to measure lactate, so as to obtain an accurate lactate concentration measurement value. The detection method has additional advantages in terms of electrochemical sensor cost and process, because it eliminates the additional demand for electrochemical sensors, and can realize HCT correction based on the existing traditional three-electrode electrochemical sensor, without adding additional HCT electrodes to the sensor, avoiding complex sensor manufacturing processes, and reducing the cost of the sensor; at the same time, HCT compensation can be realized without increasing the sampling volume.

[0005] A first aspect of the present invention is to provide an electrochemical detection system with HCT correction function, for improving the accuracy of measuring the lactate concentration of a blood sample, comprising:

[0006] It includes an electrochemical sensor, a main control module, an HCT resistance acquisition module, a double-pole double-throw switch module, a constant potential circuit module, a three-electrode current acquisition module, a temperature acquisition module and a display module; wherein:

[0007] The electrochemical sensor is provided with a three-electrode system, and the three-electrode system comprises a reference electrode, an auxiliary electrode and a working electrode;

[0008] The HCT resistance acquisition module measures the resistance of the blood sample based on the reference electrode and the auxiliary electrode, and determines the current HCT value of the blood sample through the linear relationship between HCT and the resistance of the blood sample;

[0009] The double-pole double-throw switch switching circuit is connected or disconnected with the three-electrode system of the electrochemical sensor; when the double-pole double-throw switch switching circuit is connected with the three-electrode system of the electrochemical sensor, the lactic acid in the blood sample undergoes an enzymatic reaction on the surface of the working electrode to form a reaction current and generate a corresponding current signal, the reference electrode provides a potential reference for the working electrode, and the auxiliary electrode and the working electrode form a current loop, which is used to measure the corresponding current signal generated by the enzymatic reaction current of the lactic acid in the blood sample; the current signal is used to obtain an initial measurement value of the lactic acid concentration in the blood sample, and the initial measurement value of the lactic acid concentration in the blood sample is calibrated to obtain a final measurement value of the lactic acid concentration in the blood sample;

[0010] The constant potential circuit module, the three-electrode current acquisition module and the main control module constitute a three-electrode data acquisition circuit; the constant potential circuit module is used to provide a constant excitation voltage for the auxiliary electrode and the reference electrode; the three-electrode current acquisition module is used to collect the reaction current on the working electrode, and convert the reaction current on the working electrode into a voltage and transmit it to the main control module; the main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value collected by the temperature acquisition module to obtain an accurate lactate concentration measurement value;

[0011] The display module is used to display the excitation voltage, the current HCT value of the blood sample, the current signal, the temperature value, time information and an accurate lactate concentration measurement value.

[0012] Preferably, the material of the reference electrode is a silver electrode or a silver chloride electrode.

[0013] Preferably, the material of the auxiliary electrode is a platinum electrode or a carbon electrode.

[0014] Preferably, a biosensitive layer is formed on the surface of the working electrode, and the lactic acid in the blood sample undergoes an enzymatic reaction through the biosensitive layer on the working electrode to form a reaction current and generate a corresponding current signal.

[0015] Preferably, the calibrating the initial lactate concentration measurement value in the blood sample to obtain the final lactate concentration measurement value in the blood sample includes: using a calibration equation related to the HCT value and the analyte concentration to calibrate the electrochemical sensor for measuring lactate so as to obtain an accurate lactate concentration measurement value.

[0016] Preferably, the HCT resistance acquisition module comprises a D / A output excitation waveform module, a reference resistor, a differential amplifier sampling resistor voltage module, a phase-sensitive demodulation resistor forward voltage module, a phase-sensitive demodulation resistor reverse voltage module, a resistor forward filter circuit module, a resistor reverse filter circuit module, an ADC2 differential acquisition voltage module, a differential amplifier sampling electrode voltage module, a phase-sensitive demodulation electrode forward voltage module, a phase-sensitive demodulation electrode reverse voltage module, an electrode forward filter circuit module, an electrode reverse filter circuit module, an ADC1 differential acquisition voltage module and a main control module; wherein:

[0017] The D / A output excitation waveform module is used to adjust the voltage of the digital / analog signal output of the main control module to a square wave with positive and negative amplitudes and output it to the solution resistance acquisition circuit composed of the reference resistor, the auxiliary electrode and the reference electrode after appropriate amplification. At this time, the double-pole double-throw switch connects the auxiliary electrode and one end of the reference resistor, and the reference electrode and the voltage modules at both ends of the differential amplifier sampling electrode are connected. The auxiliary electrode and the reference electrode constitute a solution resistance acquisition electrode;

[0018] The voltage module across the differential amplifier sampling resistor is used to sample the voltage across the reference resistor;

[0019] Inputting the voltage across the reference resistor into the phase-sensitive demodulation resistor forward voltage module and the phase-sensitive demodulation resistor reverse voltage module for phase-sensitive demodulation to obtain a first forward voltage signal and a first reverse voltage signal;

[0020] The first forward voltage signal and the first reverse voltage signal are respectively transmitted to the resistor forward filter circuit module and the resistor reverse filter circuit module for signal filtering to obtain a second forward voltage signal and a second reverse voltage signal;

[0021] The ADC2 differential voltage acquisition module is used to acquire the difference between the second forward voltage and the second reverse voltage to obtain the voltage on the reference resistor, thereby obtaining the reaction current on the working electrode;

[0022] The voltage module at both ends of the differential amplifier sampling electrode is used to collect the voltage at both ends of the working electrode, and obtain a third forward voltage signal and a third reverse voltage signal through phase-sensitive demodulation of the phase-sensitive demodulation electrode forward voltage module and the phase-sensitive demodulation electrode reverse voltage module;

[0023] The third forward voltage signal and the third reverse voltage signal are respectively transmitted to the electrode forward filtering circuit module and the electrode reverse filtering circuit module for signal filtering to obtain a fourth forward voltage signal and a fourth reverse voltage signal;

[0024] The ADC1 differential voltage acquisition module is used to acquire the difference between the fourth forward voltage signal and the fourth reverse voltage signal to obtain the voltage on the reference resistor, so as to calculate the resistance of the solution at this time.

[0025] Preferably, the main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value acquired by the temperature acquisition module, and obtaining an accurate lactate concentration measurement value includes: performing temperature compensation for the resistance of the solution at this time through the main control module, thereby obtaining an accurate resistance value of the solution.

[0026] Preferably, a three-electrode acquisition circuit is formed based on the constant potential circuit module, the three-electrode data acquisition module and the main control module, and the double-pole double-throw switch connects the auxiliary electrode and the constant potential circuit module, and connects the reference electrode and the constant potential circuit module, so that the reference electrode serves as a reference standard for the working electrode, and transmits current to the working electrode through the auxiliary electrode, so that a reaction occurs on the working electrode.

[0027] The second aspect of the present invention is to provide an electrochemical detection method with HCT correction function, which is implemented based on the detection system of the first aspect and includes:

[0028] S1, adding the blood pressure sample to be measured into the electrochemical sensor so that the reference electrode, the auxiliary electrode and the working electrode are completely immersed in the blood sample to be measured;

[0029] S2, connecting the double-pole double-throw switch to the HCT resistance acquisition module through the double-pole double-throw switch switching module to acquire the resistance value of the blood sample to be tested;

[0030] S3, determining a current HCT value in the blood sample based on a linear correlation between the HCT value and the resistance value of the blood sample;

[0031] S4, the main control module controls the double-pole double-throw switch switching module to connect the three-electrode system on the electrochemical sensor, and the lactic acid in the blood sample undergoes an enzymatic reaction on the surface of the working electrode to form a reaction current and generate a corresponding current signal;

[0032] S5, the main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value acquired by the temperature acquisition module to obtain an accurate lactate concentration measurement value.

[0033] As a preferred embodiment, the detection method further comprises:

[0034] S6, the display module displays the excitation voltage, the current HCT value of the blood sample, the current signal, the temperature value, time information and the accurate lactate concentration measurement value.

[0035] Beneficial effects of the method and system of the present invention:

[0036] (1) The detection system is based on a traditional three-electrode electrochemical sensor. The circuit is switched by a double-pole double-throw switch to connect the auxiliary electrode and the reference electrode on the electrochemical sensor in sequence to measure the resistance of the blood sample. The current HCT in the blood is converted based on the linear relationship between HCT and the resistance of the blood sample. Then, the three-electrode system (working electrode, auxiliary electrode and reference electrode) on the electrochemical sensor is connected through circuit switching to measure the lactate current in the blood sample. Finally, the calibration equation related to the HCT value and the analyte concentration is used to calibrate the electrochemical sensor to measure lactate, so as to obtain an accurate lactate concentration measurement value.

[0037] (2) The detection method of the present invention has additional advantages in terms of electrochemical sensor cost and process because it eliminates the additional demand for electrochemical sensors. HCT correction can be achieved based on the existing traditional three-electrode electrochemical sensor without adding additional HCT electrodes to the sensor, thus avoiding complex sensor manufacturing processes and reducing sensor costs. At the same time, HCT compensation can be achieved without increasing the sampling volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A circuit schematic diagram of a preferred embodiment of the present invention;

[0040] Figure 2 This is a HCT resistance acquisition circuit and constant potential circuit diagram provided for a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] This embodiment provides an electrochemical detection system with HCT correction function, which is used to improve the accuracy of measuring the lactate concentration of a blood sample, including:

[0045] It includes an electrochemical sensor, a main control module, an HCT resistance acquisition module, a double-pole double-throw switch module, a constant potential circuit module, a three-electrode current acquisition module, a temperature acquisition module and a display module; wherein:

[0046] The electrochemical sensor is provided with a three-electrode system, and the three-electrode system comprises a reference electrode, an auxiliary electrode and a working electrode;

[0047] The HCT resistance acquisition module measures the resistance of the blood sample based on the reference electrode and the auxiliary electrode, and converts the current HCT value of the blood sample through the linear relationship between HCT and the resistance of the blood sample;

[0048] The double-pole double-throw switch switching circuit is connected or disconnected with the three-electrode system of the electrochemical sensor; when the double-pole double-throw switch switching circuit is connected with the three-electrode system of the electrochemical sensor, the lactic acid in the blood sample undergoes an enzymatic reaction on the surface of the working electrode to form a reaction current and generate a corresponding current signal, the reference electrode provides a potential reference for the working electrode, and the auxiliary electrode and the working electrode form a current loop, which is used to measure the enzymatic reaction current of lactic acid in the blood sample; finally, the calibration equation related to the HCT value and the analyte concentration is used to realize the calibration of the electrochemical sensor for measuring lactic acid, so as to obtain an accurate lactic acid concentration measurement value;

[0049] The constant potential circuit module, the three-electrode current acquisition module and the main control module constitute a three-electrode data acquisition circuit; the constant potential circuit module is used to provide a constant excitation voltage for the auxiliary electrode and the reference electrode; the three-electrode current acquisition module is used to collect the reaction current on the working electrode, and convert the reaction current on the working electrode into a voltage and transmit it to the main control module; the main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value collected by the temperature acquisition module to obtain an accurate lactate concentration measurement value;

[0050] The display module is used to display the excitation voltage, the current HCT value of the blood sample, the current signal, the temperature value, time information and an accurate lactate concentration measurement value.

[0051] As a preferred embodiment, the material of the reference electrode is a silver electrode or a silver chloride electrode.

[0052] As a preferred embodiment, the material of the auxiliary electrode is a platinum electrode or a carbon electrode.

[0053] As a preferred embodiment, a biosensitive layer is formed on the surface of the working electrode, and the lactic acid in the blood sample undergoes an enzymatic reaction through the biosensitive layer on the working electrode to form a reaction current and generate a corresponding current signal.

[0054] As a preferred embodiment, the HCT resistance acquisition module includes a D / A output excitation waveform module, a reference resistor, a differential amplifier sampling resistor voltage module, a phase-sensitive demodulation resistor forward voltage module, a phase-sensitive demodulation resistor reverse voltage module, a resistor forward filter circuit module, a resistor reverse filter circuit module, an ADC2 differential acquisition voltage module, a differential amplifier sampling electrode voltage module, a phase-sensitive demodulation electrode forward voltage module, a phase-sensitive demodulation electrode reverse voltage module, an electrode forward filter circuit module, an electrode reverse filter circuit module and an ADC1 differential acquisition voltage module and a main control module; wherein:

[0055] The D / A output excitation waveform module is used to adjust the voltage of the digital / analog signal output of the main control module to a square wave with positive and negative amplitudes and output it to the solution resistance acquisition circuit composed of the reference resistor, the auxiliary electrode and the reference electrode after appropriate amplification. At this time, the double-pole double-throw switch connects the auxiliary electrode and one end of the reference resistor, and the reference electrode and the voltage modules at both ends of the differential amplifier sampling electrode are connected. The auxiliary electrode and the reference electrode constitute a solution resistance acquisition electrode;

[0056] The voltage module across the differential amplifier sampling resistor is used to sample the voltage across the reference resistor;

[0057] Inputting the voltage across the reference resistor into the phase-sensitive demodulation resistor forward voltage module and the phase-sensitive demodulation resistor reverse voltage module for phase-sensitive demodulation to obtain a first forward voltage signal and a first reverse voltage signal;

[0058] The first forward voltage signal and the first reverse voltage signal are respectively transmitted to the resistor forward filter circuit module and the resistor reverse filter circuit module for signal filtering to obtain a second forward voltage signal and a second reverse voltage signal;

[0059] The ADC2 differential voltage acquisition module is used to acquire the difference between the second forward voltage and the second reverse voltage to obtain the voltage on the reference resistor, thereby obtaining the reaction current on the working electrode;

[0060] Similarly, the voltage module at both ends of the differential amplifier sampling electrode is used to collect the voltage at both ends of the working electrode, and obtains a third forward voltage signal and a third reverse voltage signal through phase-sensitive demodulation of the phase-sensitive demodulation electrode forward voltage module and the phase-sensitive demodulation electrode reverse voltage module;

[0061] The third forward voltage signal and the third reverse voltage signal are respectively transmitted to the electrode forward filtering circuit module and the electrode reverse filtering circuit module for signal filtering to obtain a fourth forward voltage signal and a fourth reverse voltage signal;

[0062] The ADC1 differential voltage acquisition module is used to acquire the difference between the fourth forward voltage signal and the fourth reverse voltage signal to obtain the voltage on the reference resistor, so as to calculate the resistance of the solution at this time.

[0063] As a preferred embodiment, the main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value acquired by the temperature acquisition module, and obtaining an accurate lactate concentration measurement value includes: performing temperature compensation for the resistance of the solution at this time through the main control module, thereby obtaining an accurate resistance value of the solution.

[0064] As a preferred embodiment, a three-electrode acquisition circuit is formed based on the constant potential circuit module, the three-electrode data acquisition module and the main control module, and the double-pole double-throw switch connects the auxiliary electrode and the constant potential circuit module, and connects the reference electrode and the constant potential circuit module, respectively, so that the reference electrode serves as a reference standard for the working electrode, and transmits current to the working electrode through the auxiliary electrode, so that a reaction occurs on the working electrode.

[0065] The second aspect of the present invention is to provide an electrochemical detection method with HCT correction function, which is implemented based on the detection system of the first aspect and includes:

[0066] S1, adding the blood pressure sample to be measured into the electrochemical sensor so that the reference electrode, the auxiliary electrode and the working electrode are completely immersed in the blood sample to be measured;

[0067] S2, connecting the double-pole double-throw switch to the HCT resistance acquisition module through the double-pole double-throw switch switching module to acquire the resistance value of the blood sample to be tested;

[0068] S3, determining a current HCT value in the blood sample based on a linear correlation between the HCT value and the resistance value of the blood sample;

[0069] S4, the main control module controls the double-pole double-throw switch switching module to connect the three-electrode system on the electrochemical sensor, and the lactic acid in the blood sample undergoes an enzymatic reaction on the surface of the working electrode to form a reaction current and generate a corresponding current signal;

[0070] S5, the main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value acquired by the temperature acquisition module to obtain an accurate lactate concentration measurement value.

[0071] As a preferred embodiment, the detection method further comprises:

[0072] S6, the display module displays the excitation voltage, the current HCT value of the blood sample, the current signal, the temperature value, time information and the accurate lactate concentration measurement value.

[0073] Application examples:

[0074] exist Figure 1 In the present embodiment, the electrochemical detection system with HCT correction includes an electrochemical sensor, a main control module, an HCT resistance acquisition module, a double-pole double-throw switch switching module, a constant potential circuit module, a three-electrode current acquisition module, a temperature acquisition module and a display module. The electrochemical sensor is provided with a reference electrode, an auxiliary electrode and a working electrode. The above electrode layer is printed on a substrate using screen printing technology. The reference electrode is a silver / silver chloride electrode, the auxiliary electrode is a platinum or carbon electrode, and the biosensitive layer formed on the surface of the working electrode, and the object to be tested reacts on the working electrode to generate a current signal.

[0075] Figure 2The operational amplifiers U10, U5, U3, U6, U7, U9, differential amplifiers U4, U8, resistors R12, R13, R14, R7, R8, R6, R9, R10, R11, capacitors C4, C5, C6, C7, C8, switches S2, S3, S4, S5, and double-pole double-throw switch S1 form a solution resistance measurement circuit. At this time, the double-pole double-throw switch is connected to 2 and 4.

[0076] Operational amplifiers U10, U5 and differential amplifiers U4, U8 are powered by dual power supplies. C4, R14 convert the D / A signal output from the main control module into a bipolar signal and transmit it to the same-direction input terminal of U10, which is amplified by U10, R12, and R13 and then output to the reference resistor R7 and the resistance measurement electrode. The differential amplifier U4 collects the voltage difference across the reference resistor R7. The positive end of R7 is connected to the reverse input terminal of U4, and the negative end of R7 is connected to the operational amplifier U5 through R8. After being followed by U5, it is connected to the positive input terminal of the differential amplifier U4. The voltage across the reference resistor R7 is phase-sensitively demodulated by S2 and S3, and then output to the follower circuit composed of U3 and U6 through the filter circuit composed of R6, C5 and R9, C6. The ADC1 differential acquisition voltage module collects the voltage difference across R7. The voltage across the reference resistor R7 is demodulated by S2 for the forward voltage and by S3 for the reverse voltage. The demodulated voltage outputs are AD_REF_P and AD_REF_N. The difference between the two is collected by the ADC2 differential voltage acquisition module, which is the voltage across the reference resistor. The current passing through the electrode can be obtained from the resistance value of the reference resistor R7 and the voltage across it.

[0077] The differential amplifier U8 collects the voltage difference between the two ends of the electrode, and after phase-sensitive demodulation by S4 and S5, it is output to the follower circuit composed of U7 and U9 through the filter circuit composed of R10, C7 and R11, C8 respectively. The ADC2 differential acquisition voltage module collects the voltage difference between the two ends. The voltage between the two ends of the electrode is demodulated by S4 for the forward voltage and by S5 for the reverse voltage. The demodulated voltage outputs are AD_POLE_P and AD_POLE_N respectively. The ADC1 differential acquisition voltage module collects the difference between the two, which is the voltage between the two ends of the electrode. The voltage VREF is half of the power supply VCC, so that the bipolar voltage of the reference resistor R7 and the two ends of the electrode is converted into a unipolar voltage, which can be directly input into the ADC module powered by a single power supply after demodulation, filtering, and following. The resistance of the solution can be obtained based on the voltage between the two ends of the electrode and the current passing through the electrode. The current HCT value in the blood is converted through the linear relationship between HCT and the resistance value of the blood sample.

[0078] Further, the double-pole double-throw switch S1 is switched, and the double-pole double-throw switch is connected to 1 and 3. Operational amplifiers U1, U2, resistors R1, R2, R3, R4, R5, capacitors C1, C2, C3, and double-pole double-throw switch S1 form a three-electrode acquisition circuit. Vmid is a constant excitation voltage, which is applied to the reference electrode so that the voltage of the reference electrode remains constant. Vmid is connected to the in-phase end of U2, that is, the potential of the working electrode is the potential relative to the reference electrode. C1 connects the reverse input and output ends of the operational amplifier U1, so that the operational amplifier U1, the reference electrode, and the auxiliary electrode form a negative feedback system. The working electrode and the auxiliary electrode form a current loop, and R3 is a current acquisition resistor. U2, R3, and R4 convert the current on the working electrode into a voltage. C2 is used to eliminate phase shift or delay in the feedback network. R5 and C3 form a filter circuit, which filters the collected voltage UOUT1 and transmits it to the main control module. The main control module determines the HCT result obtained by the HCT resistance acquisition module and the temperature acquired by the temperature acquisition module to correct the measurement result to obtain an accurate lactic acid concentration.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electrochemical detection system with HCT correction function, characterized in that: Used to improve the accuracy of lactate concentration measurement in blood samples, including: It includes an electrochemical sensor, a main control module, an HCT resistance acquisition module, a double-pole double-throw switch module, a constant potential circuit module, a three-electrode current acquisition module, a temperature acquisition module and a display module; wherein: The electrochemical sensor is provided with a three-electrode system, and the three-electrode system comprises a reference electrode, an auxiliary electrode and a working electrode; The HCT resistance acquisition module measures the resistance of the blood sample based on the reference electrode and the auxiliary electrode, and determines the current HCT value of the blood sample through the linear relationship between HCT and the resistance of the blood sample; The double-pole double-throw switch switching module is connected or disconnected with the three-electrode system of the electrochemical sensor; when the double-pole double-throw switch switching module is connected with the three-electrode system of the electrochemical sensor, the lactic acid in the blood sample undergoes an enzymatic reaction on the surface of the working electrode to form a reaction current and generate a corresponding current signal, the reference electrode provides a potential reference for the working electrode, and the auxiliary electrode and the working electrode form a current loop, which is used to measure the corresponding current signal generated by the enzymatic reaction current of the lactic acid in the blood sample; the current signal is used to obtain the initial lactic acid concentration measurement value in the blood sample, and the initial lactic acid concentration measurement value in the blood sample is calibrated to obtain the final lactic acid concentration measurement value in the blood sample; The constant potential circuit module, the three-electrode current acquisition module and the main control module constitute a three-electrode data acquisition circuit; the constant potential circuit module is used to provide a constant excitation voltage for the auxiliary electrode and the reference electrode; the three-electrode current acquisition module is used to collect the reaction current on the working electrode, and convert the reaction current on the working electrode into a voltage and transmit it to the main control module; the main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value collected by the temperature acquisition module to obtain an accurate lactate concentration measurement value; The display module is used to display the excitation voltage, the current HCT value of the blood sample, the current signal, the temperature value, time information and an accurate lactate concentration measurement value.

2. The electrochemical detection system with HCT correction function according to claim 1, characterized in that: The material of the reference electrode is a silver electrode or a silver chloride electrode.

3. The electrochemical detection system with HCT correction function according to claim 1, characterized in that: The auxiliary electrode is made of platinum electrode or carbon electrode.

4. The electrochemical detection system with HCT correction function according to claim 1, characterized in that: A biosensitive layer is formed on the surface of the working electrode, and the lactic acid in the blood sample undergoes an enzymatic reaction through the biosensitive layer on the working electrode to form a reaction current and generate a corresponding current signal.

5. An electrochemical detection system with HCT correction function according to any one of claims 1 to 4, characterized in that: The step of calibrating the initial lactate concentration measurement value in the blood sample to obtain the final lactate concentration measurement value in the blood sample includes: using a calibration equation related to the HCT value and the analyte concentration to calibrate the electrochemical sensor for measuring lactate so as to obtain an accurate lactate concentration measurement value.

6. The electrochemical detection system with HCT correction function according to claim 5, characterized in that: The HCT resistance acquisition module includes a D / A output excitation waveform module, a reference resistor, a differential amplifier sampling resistor voltage module, a phase-sensitive demodulation resistor forward voltage module, a phase-sensitive demodulation resistor reverse voltage module, a resistor forward filter circuit module, a resistor reverse filter circuit module, an ADC2 differential acquisition voltage module, a differential amplifier sampling electrode voltage module, a phase-sensitive demodulation electrode forward voltage module, a phase-sensitive demodulation electrode reverse voltage module, an electrode forward filter circuit module, an electrode reverse filter circuit module, an ADC1 differential acquisition voltage module and a main control module; wherein: The D / A output excitation waveform module is used to adjust the voltage of the digital / analog signal output of the main control module to a square wave with positive and negative amplitudes and output it to the solution resistance acquisition circuit composed of the reference resistor, the auxiliary electrode and the reference electrode after appropriate amplification. At this time, the double-pole double-throw switch connects the auxiliary electrode and one end of the reference resistor, and the reference electrode and the voltage modules at both ends of the differential amplifier sampling electrode are connected. The auxiliary electrode and the reference electrode constitute a solution resistance acquisition electrode; The voltage module across the differential amplifier sampling resistor is used to sample the voltage across the reference resistor; Inputting the voltage across the reference resistor into the phase-sensitive demodulation resistor forward voltage module and the phase-sensitive demodulation resistor reverse voltage module for phase-sensitive demodulation to obtain a first forward voltage signal and a first reverse voltage signal; The first forward voltage signal and the first reverse voltage signal are respectively transmitted to the resistor forward filter circuit module and the resistor reverse filter circuit module for signal filtering to obtain a second forward voltage signal and a second reverse voltage signal; The ADC2 differential voltage acquisition module is used to acquire the difference between the second forward voltage and the second reverse voltage to obtain the voltage on the reference resistor, thereby obtaining the reaction current on the working electrode; The voltage module at both ends of the differential amplifier sampling electrode is used to collect the voltage at both ends of the working electrode, and obtain a third forward voltage signal and a third reverse voltage signal through phase-sensitive demodulation of the phase-sensitive demodulation electrode forward voltage module and the phase-sensitive demodulation electrode reverse voltage module; The third forward voltage signal and the third reverse voltage signal are respectively transmitted to the electrode forward filtering circuit module and the electrode reverse filtering circuit module for signal filtering to obtain a fourth forward voltage signal and a fourth reverse voltage signal; The ADC1 differential voltage acquisition module is used to acquire the difference between the fourth forward voltage signal and the fourth reverse voltage signal to obtain the voltage on the reference resistor, so as to calculate the resistance of the solution at this time.

7. The electrochemical detection system with HCT correction function according to claim 6, characterized in that: The main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value acquired by the temperature acquisition module, and obtaining an accurate lactate concentration measurement value includes: performing temperature compensation on the resistance of the solution at this time through the main control module, thereby obtaining an accurate resistance value of the solution.

8. The electrochemical detection system with HCT correction function according to claim 7, characterized in that: A three-electrode acquisition circuit is formed based on the constant potential circuit module, the three-electrode data acquisition module and the main control module. The double-pole double-throw switch connects the auxiliary electrode to the constant potential circuit module and the reference electrode to the constant potential circuit module, respectively, so that the reference electrode serves as a reference standard for the working electrode, and transmits current to the working electrode through the auxiliary electrode, so that a reaction occurs on the working electrode.

9. An electrochemical detection method with HCT correction function, implemented based on the detection system according to any one of claims 1 to 8, characterized in that: include: S1, adding the blood sample to be tested into the electrochemical sensor so that the reference electrode, the auxiliary electrode and the working electrode are completely immersed in the blood sample to be tested; S2, connecting the double-pole double-throw switch to the HCT resistance acquisition module through the double-pole double-throw switch switching module to acquire the resistance value of the blood sample to be tested; S3, determining a current HCT value in the blood sample based on a linear correlation between the HCT value and the resistance value of the blood sample; S4, the main control module controls the double-pole double-throw switch switching module to connect the three-electrode system on the electrochemical sensor, and the lactic acid in the blood sample undergoes an enzymatic reaction on the surface of the working electrode to form a reaction current and generate a corresponding current signal; S5, the main control module corrects the lactate concentration measurement value of the blood sample based on the current HCT value of the blood sample obtained by the HCT resistance acquisition module and the temperature value acquired by the temperature acquisition module to obtain an accurate lactate concentration measurement value.

10. The electrochemical detection method with HCT correction function according to claim 9, characterized in that: The detection method further comprises: S6, the display module displays the excitation voltage, the current HCT value of the blood sample, the current signal, the temperature value, time information and the accurate lactate concentration measurement value.

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