CN216747538U - Electrochemical analysis sensitivity self-adjusting device suitable for on-site rapid detection - Google Patents

Abstract

The utility model provides a self-adjusting device for electrochemical analysis sensitivity suitable for on-site rapid detection. The self-adjusting device includes a constant potential circuit, and also includes a mobile terminal for analyzing the current data obtained from the detection; during electrochemical detection, the constant potential The circuit applies voltage waveform excitation to the substance to be tested, and samples the response current of the substance to be tested through the analog-to-digital conversion module for analysis; the constant potential circuit includes a programmable digital potentiometer chip; the digital potentiometer chip is used for electrical The feedback loop resistance adjustment when the chemical analysis sensitivity is automatically adjusted; when the mobile terminal determines that the current data measured during the detection process does not match the current sensitivity of the potentiostatic circuit, the digital potentiometer chip automatically adjusts the resistance value of the potentiometer to change the response current return The resistance value of the circuit matches the current analysis sensitivity of the potentiostatic circuit with the current electrochemical detection, and the utility model can realize the automatic adjustment of the current analysis sensitivity during electrochemical detection.

Description

A self-adjusting device for electrochemical analysis sensitivity suitable for on-site rapid detection

technical field

The utility model relates to the technical field of electrochemical detection, in particular to an electrochemical analysis sensitivity self-adjusting device suitable for on-site rapid detection.

Background technique

The analytical sensitivity of the response current of the existing portable electrochemical detection devices and methods often has to be manually selected when performing electrochemical detection, and some devices and methods use a fixed single current analytical sensitivity. Manual selection of amperometric sensitivity will lead to too cumbersome and inefficient electrochemical detection, making the detection not simple enough, and a fixed single amperometric sensitivity will inevitably lead to insufficient response current detection accuracy.

SUMMARY OF THE INVENTION

The utility model provides an electrochemical analysis sensitivity self-adjusting device suitable for on-site rapid detection, which can realize the automatic adjustment of the current analysis sensitivity during electrochemical detection.

The utility model adopts the following technical solutions.

A self-adjusting device for electrochemical analysis sensitivity suitable for on-site rapid detection, the self-adjusting device includes a potentiostatic circuit, and also includes a mobile terminal for analyzing current data obtained from the detection;

The circuit composition of the constant potential circuit includes an MCU microcontroller module for controlling a digital potentiometer chip, and also includes a voltage follower module, an analog-to-digital conversion module, a digital-to-analog conversion module, an electrode interface module, and a low-pass filter module. , TIA transimpedance amplifier module, internal zero module, reference voltage source module, Bluetooth module, digital potentiometer module; during electrochemical detection, the constant potential circuit applies voltage waveform excitation to the substance to be tested, and the substance to be tested is sampled by the analog-to-digital conversion module The response current is used for analysis; the constant potential circuit includes a programmable digital potentiometer chip;

The digital potentiometer chip is used for feedback loop resistance adjustment when the sensitivity of electrochemical analysis is automatically adjusted; when the mobile terminal determines that the current data measured in the detection process does not match the current sensitivity of the potentiostatic circuit, the digital potentiometer chip automatically adjusts the potentiometer. In order to change the resistance value of the response current return circuit, the current analysis sensitivity of the potentiostatic circuit can be matched with the current electrochemical detection.

The mobile terminal is installed with an electrochemical detection APP; when the potentiostatic circuit performs electrochemical detection, the potentiostatic circuit sends the real-time current data obtained by the detection to the electrochemical detection APP, and lists the current data in the mobile terminal. storage.

In the self-adjusting device, the method for determining and automatically adjusting that the amperometric sensitivity is too high is specifically: an integer variable A is designed in the amperometric sensitivity abnormal capture code of the electrochemical detection APP, and during the electrochemical detection process, the The integer variable A is the sum of the current data whose absolute value is greater than or equal to the upper limit of the current detection range in the current data list. When the value of the integer variable A is greater than or equal to the preset threshold B, the electrochemical detection APP judges the detection. During the process, the abnormal behavior of the current analysis sensitivity is too high. The potentiostatic circuit automatically adjusts the resistance of the response current return circuit, and restarts the detection, so that the current analysis sensitivity of the potentiostatic circuit matches the current electrochemical detection.

In the self-adjusting device, the automatic adjustment method for the low sensitivity of the current analysis is: at the end of a single electrochemical detection, the maximum and minimum current values in the current data list are subtracted to obtain a maximum and minimum current difference; Compare the maximum and minimum current difference with the current detection range limit. If the difference between the maximum current and the minimum current is less than or equal to half of the current detection range limit, the electrochemical detection APP judges that the current analysis sensitivity is too low during the detection process. If the abnormal phenomenon occurs, the potentiostatic circuit automatically increases the resistance of the response current return circuit, and restarts the detection, so that the current analysis sensitivity of the potentiostatic circuit matches the current electrochemical detection.

When the resistance value of the response current return circuit is automatically adjusted by the digital potentiometer chip, the adjustment size of each resistance value is 10% of the current digital potentiometer resistance output value, and the adjustment range of the resistance is 100Ω~100kΩ.

The mobile terminal is installed with an electrochemical detection APP; the functions of the electrochemical detection APP include detection parameter setting of cyclic voltammetry, detection state control, and real-time detection voltammogram drawing.

The digital potentiometer chip is connected with the mobile terminal in a bluetooth manner; the constant potential circuit includes an MCU microcontroller module for the digital potentiometer chip, and also includes a voltage follower module, an analog-to-digital conversion module, a digital-to-analog conversion module, Electrode interface module, low-pass filter module, TIA transimpedance amplifier module, internal zero module, reference voltage source module, Bluetooth module, digital potentiometer module.

The MCU microcontroller module is STM32F103RCT6; the voltage follower module is AD8608; the analog-to-digital conversion module is AD7694; the digital-to-analog conversion module is AD5541; the internal zero module is ADR4520; the reference voltage source The module is ADR4540; the bluetooth module is HC-05; the digital potentiometer module is AD5270.

The electrochemical detection is based on the redox reaction of the substance. In the detection, a specific voltage excitation waveform is applied to the aqueous solution containing the substance to be tested through an electrochemical three-electrode system, so that the substance to be tested will undergo oxidation on the electrode surface to gain and lose electrons. The reduction reaction generates a response current, and the generated response current flows through the response current return circuit formed by the counter electrode and the working electrode, and the response current return circuit is connected with the current feedback resistance of the digital potentiometer, and the digital potentiometer The adjustment of the output resistance value changes the resistance value of the response current return circuit, and automatically makes the current analysis sensitivity of the potentiostatic circuit match the current electrochemical detection, so that the potentiostatic circuit can quantitatively judge the substance to be tested by analyzing the response current value. concentration.

The solution of the present utility model can automatically adjust the sensitivity of the current analysis in the process of electrochemical detection for abnormal detection behaviors with high amperometric sensitivity and low amperometric sensitivity. It judges whether the current detection and analysis sensitivity state is normal, and has corresponding codes and functions to capture the abnormal current analysis sensitivity. After catching the abnormal sensitivity of the current analysis, this scheme will automatically adjust the resistance value of the current feedback resistance of the digital potentiometer, and automatically match the best sensitivity of the current analysis for the electrochemical detection, so as to improve the accuracy of the electrochemical detection.

Compared with the traditional technology, the digital potentiometer module on the potentiostatic circuit of the present invention can automatically realize the self-adjustment of the sensitivity of the current analysis through an automatic scheme (such as programmable firmware), which improves the accuracy of the current detection and the accuracy of the electrochemical detection. Accuracy. Compared with the electrochemical detection device that needs to manually adjust the amperometric sensitivity, the device eliminates the tedious process of manual operation and improves the automation degree of electrochemical detection; compared with the electrochemical detection with only a single amperometric sensitivity The device has the advantage of self-adjustment of the current analysis sensitivity, and the current detection accuracy and current detection sensitivity are greatly improved. The device and method are extremely suitable for electrochemical analysis needs in the field of rapid on-site detection (for example, various POCT [Point-of-care testing] devices based on electrochemical methods).

Description of drawings

Below in conjunction with the accompanying drawings and specific embodiments, the present utility model is described in further detail:

Accompanying drawing 1 is the operation flow schematic diagram of the present utility model;

Accompanying drawing 2 is the working principle schematic diagram of the present utility model;

Accompanying drawing 3 is the sensitivity automatic adjustment schematic diagram of the present utility model;

Figure 4 is a schematic diagram of the principle of part of the circuit of the present invention.

Detailed ways

As shown in the figure, a self-adjusting device for electrochemical analysis sensitivity suitable for on-site rapid detection, the self-adjusting device includes a potentiostatic circuit, and also includes a mobile terminal for analyzing the current data obtained from the detection; The circuit composition includes the MCU microcontroller module used to control the digital potentiometer chip, as well as the voltage follower module, the analog-to-digital conversion module, the digital-to-analog conversion module, the electrode interface module, the low-pass filter module, and the TIA transimpedance amplifier module. , Internal zero module, reference voltage source module, Bluetooth module, digital potentiometer module; during electrochemical detection, the constant potential circuit applies voltage waveform excitation to the substance to be tested, and the response current of the substance to be tested is sampled by the analog-to-digital conversion module for analysis. The constant potential circuit includes a programmable digital potentiometer chip; the digital potentiometer chip is used for feedback loop resistance adjustment when the sensitivity of electrochemical analysis is automatically adjusted; when the mobile terminal determines that the current data measured in the detection process is consistent with the constant When the current sensitivity of the potential circuit does not match, the digital potentiometer chip automatically adjusts the resistance value of the potentiometer to change the resistance value of the response current return circuit, so that the current analysis sensitivity of the potentiostatic circuit matches the current electrochemical detection.

The mobile terminal is installed with an electrochemical detection APP; when the potentiostatic circuit performs electrochemical detection, the potentiostatic circuit sends the real-time current data obtained by the detection to the electrochemical detection APP, and lists the current data in the mobile terminal. storage.

In the self-adjusting device, the method for determining and automatically adjusting that the amperometric sensitivity is too high is specifically: an integer variable A is designed in the amperometric sensitivity abnormal capture code of the electrochemical detection APP, and during the electrochemical detection process, the The integer variable A is the sum of the current data whose absolute value is greater than or equal to the upper limit of the current detection range in the current data list. When the value of the integer variable A is greater than or equal to the preset threshold B, the electrochemical detection APP judges the detection. During the process, the abnormal behavior of the current analysis sensitivity is too high. The potentiostatic circuit automatically adjusts the resistance of the response current return circuit, and restarts the detection, so that the current analysis sensitivity of the potentiostatic circuit matches the current electrochemical detection.

The preset threshold B is an integer of 20,

In the self-adjusting device, the automatic adjustment method for the low sensitivity of the current analysis is: at the end of a single electrochemical detection, the maximum and minimum current values in the current data list are subtracted to obtain a maximum and minimum current difference; Compare the maximum and minimum current difference with the current detection range limit. If the difference between the maximum current and the minimum current is less than or equal to half of the current detection range limit, the electrochemical detection APP judges that the current analysis sensitivity is too low during the detection process. If the abnormal phenomenon occurs, the potentiostatic circuit automatically increases the resistance of the response current return circuit, and restarts the detection, so that the current analysis sensitivity of the potentiostatic circuit matches the current electrochemical detection.

When the resistance value of the response current return circuit is automatically adjusted by the digital potentiometer chip, the adjustment value of each resistance value is 10% of the current digital potentiometer resistance output value, and the adjustment range of the resistance is 100Ω~100kΩ;

When the total output resistance range of the potentiometer is within 100KΩ and the output resistance resolution is 10 bits, the method of self-adjustment and adjustment is adopted when adjusting the resistance value of the current feedback resistance of the potentiometer, specifically:

If the current output resistance of the potentiometer is in the range of 10~100KΩ, the resistance adjustment value is 10kΩ during each self-adjustment;

If the current output resistance of the potentiometer is in the range of 1~10kΩ, the resistance adjustment value is 1KΩ during each self-adjustment;

If the current output resistance of the potentiometer is in the range of 100~1000Ω, the resistance adjustment value is 100Ω during each self-adjustment.

The mobile terminal is installed with an electrochemical detection APP; the functions of the electrochemical detection APP include detection parameter setting of cyclic voltammetry, detection state control, and real-time detection voltammogram drawing.

The digital potentiometer chip is connected with the mobile terminal in a bluetooth manner; the constant potential circuit includes an MCU microcontroller module for the digital potentiometer chip, and also includes a voltage follower module, an analog-to-digital conversion module, a digital-to-analog conversion module, Electrode interface module, low-pass filter module, TIA transimpedance amplifier module, internal zero module, reference voltage source module, Bluetooth module, digital potentiometer module.

The MCU microcontroller module is STM32F103RCT6; the voltage follower module is AD8608; the analog-to-digital conversion module is AD7694; the digital-to-analog conversion module is AD5541; the internal zero module is ADR4520; the reference voltage source The module is ADR4540; the bluetooth module is HC-05; the digital potentiometer module is AD5270.

The electrochemical detection is based on the redox reaction of the substance. In the detection, a specific voltage excitation waveform is applied to the aqueous solution containing the substance to be tested through an electrochemical three-electrode system, so that the substance to be tested will undergo oxidation on the electrode surface to gain and lose electrons. The reduction reaction generates a response current, and the generated response current flows through the response current return circuit formed by the counter electrode and the working electrode, and the response current return circuit is connected with the current feedback resistance of the digital potentiometer, and the digital potentiometer The adjustment of the output resistance value changes the resistance value of the response current return circuit, and automatically makes the current analysis sensitivity of the potentiostatic circuit match the current electrochemical detection, so that the potentiostatic circuit can quantitatively judge the substance to be tested by analyzing the response current value. concentration.

Example:

In this example, a smart phone is used as a mobile terminal. When performing electrochemical detection and analysis, the potentiostatic circuit part of the device is first powered on. After the potentiostatic circuit is powered on, the initialization operation will be performed automatically.

Open the electrochemical detection APP installed on the mobile terminal. After opening the electrochemical detection APP, first enter the parameter setting interface of cyclic voltammetry. In the parameter setting interface, you can set the upper limit potential, lower limit potential and voltage scan rate of cyclic voltammetry detection. , the setting of parameters such as the number of detection cycles.

Before the test is officially started, the Bluetooth connection between the electrochemical detection APP and the potentiostatic circuit should be completed first. After the Bluetooth connection is successful, click the start detection button. The potential circuit is turned on for detection at this time, and the potentiostatic circuit applies a specific voltage excitation waveform to the substance to be tested, and samples and converts the response current in real time. The voltammetry curve is drawn in real time on the detection interface. While the electrochemical APP draws the voltammetry curve, the APP is also monitoring the sensitivity state of the current analysis.

Under the traditional technology, in electrochemical detection, if the sensitivity of amperometric analysis is too high, the over-range problem of current detection is prone to occur in electrochemical detection, which is manifested as peak clipping phenomenon in the detection voltammetry result graph; and when the sensitivity of amperometric analysis is too low When the test voltammetry result graph appears short and flat, the above two voltammetry graphs are not conducive to the observation of the test result.

In the device described in this example, once the response current analysis sensitivity is detected abnormal detection behavior, the APP will automatically restart the detection immediately, and at the same time restart the detection, reconfigure the resistance value of the current feedback resistance of the digital potential chip on the circuit through the program size, automatic adjustment of the amperometric sensitivity, and automatic matching of the optimal amperometric sensitivity for electrochemical detection.

In this example, the purpose of the automatic adjustment of the sensitivity of the amperometric analysis is to adjust the response current of the substance to be tested received by the analysis circuit of the potentiostatic circuit to match the sensitivity of the analysis circuit.

Claims (2)

1. A self-adjusting device for electrochemical analysis sensitivity suitable for on-site rapid detection is characterized in that: the self-adjusting device comprises a potentiostatic circuit, and also includes a mobile terminal that analyzes the current data obtained from the detection; The circuit composition of the constant potential circuit includes an MCU microcontroller module for controlling a digital potentiometer chip, and also includes a voltage follower module, an analog-to-digital conversion module, a digital-to-analog conversion module, an electrode interface module, and a low-pass filter module. , TIA transimpedance amplifier module, internal zero module, reference voltage source module, Bluetooth module, digital potentiometer module; during electrochemical detection, the constant potential circuit applies voltage waveform excitation to the substance to be tested, and the substance to be tested is sampled by the analog-to-digital conversion module The response current is used for analysis; the constant potential circuit includes a programmable digital potentiometer chip; The digital potentiometer chip is used for feedback loop resistance adjustment when the sensitivity of electrochemical analysis is automatically adjusted; when the mobile terminal determines that the current data measured in the detection process does not match the current sensitivity of the potentiostatic circuit, the digital potentiometer chip automatically adjusts the potentiometer. In order to change the resistance value of the response current return circuit, the current analysis sensitivity of the potentiostatic circuit can be matched with the current electrochemical detection. 2. a kind of electrochemical analysis sensitivity self-adjustment device suitable for on-site rapid detection according to claim 1, is characterized in that: described MCU microcontroller module is STM32F103RCT6; Described voltage follower module is AD8608; The analog-to-digital conversion module is AD7694; the digital-to-analog conversion module is AD5541; the internal zero module is ADR4520; the reference voltage source module is ADR4540; the Bluetooth module is HC-05; the digital potentiometer module is AD5270 .

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