CN212622387U - Portable electrochemical workstation circuit - Google Patents
Portable electrochemical workstation circuit Download PDFInfo
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- CN212622387U CN212622387U CN202020961637.8U CN202020961637U CN212622387U CN 212622387 U CN212622387 U CN 212622387U CN 202020961637 U CN202020961637 U CN 202020961637U CN 212622387 U CN212622387 U CN 212622387U
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Abstract
The utility model provides a portable electrochemistry workstation circuit can be applied to the three electrode electrochemistry detection occasion of trace characteristic thing, has advantages such as small, with low costs, easy to use and carry, measurement accuracy height. The device comprises a control circuit, a reference voltage generating circuit, a potentiostat circuit, a three-electrode sensor, a micro-current detection circuit, a serial port output circuit and a power supply circuit for providing a working power supply for the modules. The high precision of system test is realized by a constant potential rectifier circuit for maintaining the voltage stability between the electrodes of the three-electrode sensor, a micro-current test circuit for testing response current and a filter circuit for removing interference.
Description
Technical Field
The utility model belongs to the technical field of the electrochemistry workstation, concretely relates to portable electrochemistry workstation circuit.
Background
With the rapid development of microelectronic technology and electrochemical detection technology, the three-electrode test system is widely applied and has important applications in the aspects of conventional electrical measurement, quantitative analysis of characteristic substances, electrochemical detection and the like. The three-electrode system includes a working electrode (Work electrode), a Reference electrode (Reference electrode), and a Counter electrode (Counter electrode), and is widely used in electrochemical analysis, and plays an important role in promoting the development of electrochemical disciplines. A common apparatus for studying three-electrode systems is an electrochemical workstation. The electrochemical workstation is short for an electrochemical measuring system. The electrochemical workstation can be used in qualitative and quantitative analysis of substances, routine electrochemical tests, research on electrochemical reaction mechanisms and the like. The electrochemical workstation has powerful functions, but is expensive, large in size and complex in operation, so that the electrochemical workstation cannot meet the detection requirement in the detection three-electrode system or the occasions requiring portable detection, and the use is limited.
Therefore, there is a need to develop a new portable electrochemical workstation circuit to solve the above problems.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a portable electrochemistry workstation circuit.
The portable electrochemical workstation circuit specifically comprises a controller, a reference voltage generating circuit, a potentiostat circuit, a three-electrode sensor, a micro-current detection circuit, a serial port output circuit and a power supply circuit. Wherein:
the controller is a micro-processing system and is provided with a digital-to-analog conversion chip communication bus interface and an analog-to-digital conversion chip communication bus interface;
the reference voltage generating circuit comprises a digital-to-analog conversion chip and an analog-to-digital conversion chip, wherein the digital-to-analog conversion chip is connected with the controller through a digital communication bus and completes digital-to-analog conversion under the control of the controller to generate an analog level signal serving as an excitation signal; the analog-to-digital conversion chip is connected with the controller through a digital communication bus, completes analog-to-digital conversion under the control of the controller, collects analog level signals, converts the analog level signals into numerical value signals, and transmits the numerical value signals to the controller through the digital communication bus.
A three-electrode sensor includes a working electrode, a counter electrode, and a reference electrode.
A potentiostat circuit comprises a comparator circuit A1 and a follower circuit A2, wherein an excitation signal generated by a reference voltage generating circuit is connected to a non-inverting input terminal of the comparator circuit A1, an output terminal of the comparator circuit A1 is connected with a reference electrode of a three-electrode sensor, a non-inverting input terminal of the follower circuit A2 is connected with a counter electrode of the three-electrode sensor, an output terminal of the follower circuit A2 is connected with an inverting input terminal of a follower circuit A2, and an output terminal of the follower circuit A2 is connected with an inverting input terminal of the comparator circuit A1.
The micro-current detection circuit comprises a voltage-current I-V conversion circuit, an amplifying circuit, a filter circuit and a sampling circuit.
Further, the digital communication bus includes I2C, SPI, serial port, parallel port, and the like.
Furthermore, the constant potential rectifier circuit can accurately apply the excitation signal generated by the reference voltage generating circuit between the working electrode and the reference electrode of the three-electrode sensor to drive the three-electrode sensor to generate electrochemical reaction to generate current.
Further, the voltage-current I-V conversion circuit in the micro-current detection circuit comprises a precision operational amplifier A3, a feedback resistor R3 and a filter capacitor C3, wherein the inverting input end of the precision operational amplifier A3 is connected with the working electrode of the three-electrode sensor, the feedback resistor R3 is connected with the filter capacitor C3 in parallel, one end of the feedback resistor is connected with the output end of the precision operational amplifier A3, and the other end of the feedback resistor is connected with the inverting input end of the precision operational amplifier A3.
Further, the feedback resistor R3 is a metal film resistor with less noise.
Further, an amplifying circuit in the micro-current detection circuit is a negative feedback circuit amplifying circuit and comprises a precision operational amplifier A4, a signal input resistor R5 and a negative feedback resistor R4.
Furthermore, a filter circuit in the micro-current detection circuit is a low-pass filter circuit and comprises a precision operational amplifier A5, a resistor R6, a resistor R7, a resistor R8, a filter capacitor C4 and a filter capacitor C5.
Furthermore, the output end of the precision operational amplifier A3 is connected with a signal input resistor R5, the other end of the signal input resistor R5 is connected with the inverting input end of the precision operational amplifier A4, and the negative feedback resistor R4 is respectively connected with the inverting input end of the precision operational amplifier A4 and the output end of the precision operational amplifier A4.
Further, the output terminal of the precision operational amplifier a4 is connected in series with the resistor R6 and the resistor R7 and is connected to the inverting input terminal of the precision operational amplifier a 5; one end of the resistor R8 is connected with the output end of the precision operational amplifier A5, and the other end is connected with the connecting end M node of the resistor R6 and the resistor R7; the filter capacitor c4 is disposed between the node M and the ground signal, and the filter capacitor c5 is disposed between the output terminal and the inverting input terminal of the precision operational amplifier A5.
The utility model discloses a control circuit determines the current time I-T curve under this potential according to the best work potential of the working electrode of three electrode sensor according to cyclic voltammetry, according to the work potential of gained, confirms the concentration of the corresponding trace characteristic thing according to I-T curve, sets for bipolar scanning circuit and produces this potential input to potentiostat circuit.
The potentiostat circuit is used to input a stable voltage signal between the reference electrode and the counter electrode of the three-electrode sensor.
The micro-current detection circuit is used for detecting micro current generated on a working electrode of the three-electrode sensor due to the existence of the micro characteristic object and inputting the micro current to the control circuit, and the control circuit judges the concentration of the micro characteristic object according to the I-T curve.
The serial port output circuit is used for outputting an upper computer through a serial port, and the upper computer software is used for processing and drawing acquired data into a curve.
The utility model has the advantages that:
(1) the utility model discloses an electrochemistry workstation circuit maintains the constant potential rectifier circuit of voltage stability between the three electrode sensor electrodes, test response current's little current test circuit, gets rid of the filter circuit of interference through the design and has realized the high accuracy of system test.
(2) The utility model discloses an electrochemistry workstation circuit adopts high integrated level circuit to the three-electrode electrochemistry detection application scene technical characteristics of trace characteristic thing, adopts microprocessor to produce different voltage waveforms through the program control DAC chip.
(3) The utility model discloses an electrochemistry workstation circuit can be applied to portable electrochemistry workstation instrument, makes it have characteristics such as small, with low costs, easy to use and carry.
Drawings
The invention is further described with the aid of the accompanying drawings, in which, however, the embodiments do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be derived from the following drawings without inventive effort.
FIG. 1 is a schematic diagram of the general circuit configuration of a portable electrochemical workstation of the present invention;
fig. 2 is a schematic circuit diagram of the portable electrochemical workstation of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
On the contrary, the invention is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in order to provide a better understanding of the present invention to the public, certain specific details are set forth in the following detailed description of the invention. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
Examples
Referring to fig. 2, the circuit design of the portable electrochemical workstation applied to the three-electrode electrochemical detection of trace features of the present invention is shown. The device comprises a control circuit, a reference voltage generating circuit, a potentiostat circuit, a three-electrode sensor, a micro-current detection circuit, a serial port output circuit and a power supply circuit for providing a working power supply for the modules.
In this embodiment, the DAC type of the digital-to-analog conversion chip AD5667 and the ADC type of the analog-to-digital conversion chip LTC 2471; their data communication bus is the I2C bus; the controller selects STM32F103RCT 6. The controller STM32F103RCT6 is respectively connected with the digital-to-analog conversion chips AD5667 analog-to-digital conversion chips LTC2471 through 12C buses.
The analog signal of the digital-to-analog conversion chip AD5667 is output to the constant potential rectifier circuit. And the potentiostat circuit is used for accurately applying an external excitation signal between the working electrode and the reference electrode of the sensor and driving the three-electrode sensor to generate electrochemical reaction to generate current.
The potentiostat circuit comprises a comparator circuit A1 and a follower circuit A2. The reference voltage generating circuit generates an excitation signal DAC _ OUT, and is connected to the non-inverting input end of the comparator circuit A1, and the output end of A1 is connected with a reference electrode RE; the non-inverting input end of the follower circuit A2 is connected with the counter electrode CE, the output end of A2 is connected with the inverting input end of A2, and meanwhile, the output end of A2 is connected with the inverting input end of A1; the comparator circuit A1 and the follower circuit A2 adopt high-precision operational amplifiers, and require low input bias current and low maximum input offset voltage. In this embodiment, the a1, a2 type AD8629 precision operational amplifier.
The current-voltage I-V conversion circuit comprises a precision operational amplifier A3, a feedback resistor R3 and a filter capacitor C3; the current output of the working electrode WE is connected with the inverting input end of A3, R3 and C3 are connected in parallel, one end of the R3 is connected with the output end of A3, and the other end of the R3 is connected with the inverting input end of A3; the feedback resistor R3 is a metal film resistor with low noise, and prevents noise from being introduced into the interference due to resistance heat.
The back stage of the I-V conversion circuit is connected with a negative feedback voltage amplifying circuit; the circuit comprises a precision operational amplifier A4, a signal input resistor R5 and a negative feedback resistor R4; the output end of the A3 of the I-V conversion circuit is connected with R5, and the other end of R5 is connected with the inverting input end of A4; r4 is respectively connected with the A4 inverting input end and the A4 output end;
the backward stage of the negative feedback voltage amplifying circuit is connected with a low-pass filter circuit; comprises a precision operational amplifier A5, resistors R6, R7 and R8; capacitance c4, c 5. The output end of the A4 is connected with the R6 and the R7 in series and is connected with the inverting input end of the A5; one end of R8 is connected with the output end of A5, the other end is connected with R6, and R7 is connected with node M; the filter capacitor C4 is arranged between the M and the ground signal; the filter capacitor c5 is disposed between the output terminal and the inverting input terminal of the A5.
The precision operational amplifiers A2, A3, A4 and A5 adopt a high-integration-level 4-precision operational amplifier chip AD8608, have low input bias current and low maximum input offset voltage, and meet the precision requirement of the embodiment.
The specific working process of the test circuit is as follows:
by adjusting the program of STM32, the DAC chip AD5667 is controlled to generate different voltage waveforms, such as cyclic volt-ampere voltage waveforms, the generated voltage signals are applied to the reference electrode RE and the counter electrode CE of the sensor through a potentiostat circuit, and the potentiostat circuit feeds back the acquired signals to the potentiostat circuit through feedback action, so that the potentials applied to the reference electrode RE and the counter electrode CE are kept at constant values. Under the driving of the potential, a faraday current is generated between the working electrode WE and the counter electrode CE, and the concentration of the trace feature can be judged by testing the magnitude of the current. Since the induced current of the three-electrode sensor is very small, 10-7And A is about right, so that the current is converted into a voltage signal by a method, the voltage is amplified, the clutter in the converted signal is processed by a wave filtering circuit, and the digital voltage signal obtained by a sampling circuit is processed and displayed.
It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single technical solution, and such description is for clarity only, and those skilled in the art should take the description as a whole, and the technical solutions in the embodiments may be combined appropriately to form other embodiments that those skilled in the art can understand. The technical details not described in detail in the present invention can be implemented by any prior art in the field. In particular, all technical features of the invention which are not described in detail can be realized by any prior art.
Claims (7)
1. A portable electrochemical workstation circuit is characterized by comprising a controller, a reference voltage generating circuit, a constant potential rectifier circuit, a three-electrode sensor, a micro-current detection circuit, a serial port output circuit and a power supply circuit;
the controller is a micro-processing system and is provided with a digital-to-analog conversion chip communication bus interface and an analog-to-digital conversion chip communication bus interface;
the reference voltage generating circuit comprises a digital-to-analog conversion chip and an analog-to-digital conversion chip, wherein the digital-to-analog conversion chip is connected with the controller through a digital communication bus, and completes digital-to-analog conversion under the control of the controller to generate an analog level signal serving as an excitation signal; the analog-to-digital conversion chip is connected with the controller through a digital communication bus, completes analog-to-digital conversion under the control of the controller, collects an analog level signal, converts the analog level signal into a numerical value signal, and transmits the numerical value signal to the controller through the digital communication bus;
the three-electrode sensor comprises a working electrode, a counter electrode and a reference electrode;
the potentiostat circuit comprises a comparator circuit A1 and a follower circuit A2, the excitation signal is connected to the non-inverting input of the comparator circuit A1, the output of the comparator circuit A1 is connected to the reference electrode, the non-inverting input of the follower circuit A2 is connected to the counter electrode, the output of the follower circuit A2 is connected to the inverting input of the follower circuit A2, and the output of the follower circuit A2 is connected to the inverting input of the comparator circuit A1;
the micro-current detection circuit comprises a voltage-current I-V conversion circuit, an amplification circuit, a filter circuit and a sampling circuit.
2. The portable electrochemical workstation circuit of claim 1, wherein the digital communication bus comprises I2C, SPI, serial port, parallel port, and the like.
3. The portable electrochemical workstation circuit of claim 1, wherein said potentiostat circuit accurately applies said excitation signal between said working electrode and said reference electrode to drive said three-electrode sensor to electrochemically react to produce an electric current.
4. The portable electrochemical workstation circuit of claim 1, wherein the voltage-to-current I-V conversion circuit comprises a precision operational amplifier A3, a feedback resistor R3, and a filter capacitor C3, wherein the inverting input terminal of the precision operational amplifier A3 is connected to the working electrode, the feedback resistor R3 and the filter capacitor C3 are connected in parallel, one end of the feedback resistor R3 is connected to the output terminal of the precision operational amplifier A3, and the other end of the feedback resistor R3 is connected to the inverting input terminal of the precision operational amplifier A3; the amplifying circuit is a negative feedback circuit amplifying circuit and comprises a precision operational amplifier A4, a signal input resistor R5 and a negative feedback resistor R4; the filter circuit is a low-pass filter circuit and comprises a precision operational amplifier A5, a resistor R6, a resistor R7, a resistor R8, a filter capacitor C4 and a filter capacitor C5.
5. The portable electrochemical workstation circuit of claim 4, wherein the feedback resistor R3 is a metal film resistor.
6. The portable electrochemical workstation circuit of claim 4, wherein the output terminal of the precision operational amplifier A3 is connected to the signal input resistor R5, the other terminal of the signal input resistor R5 is connected to the inverting input terminal of the precision operational amplifier A4, and the negative feedback resistor R4 is connected to the inverting input terminal of the precision operational amplifier A4 and the output terminal of the precision operational amplifier A4, respectively.
7. The portable electrochemical workstation circuit of claim 4, wherein the output of the precision operational amplifier A4 is connected in series with the resistor R6 and the resistor R7 and is connected to the inverting input of the precision operational amplifier A5; one end of the resistor R8 is connected with the output end of the precision operational amplifier A5, and the other end of the resistor R8 is connected with the connecting end M node of the resistor R6 and the resistor R7; the filter capacitor C4 is disposed between the M node and ground, and the filter capacitor C5 is disposed between the output terminal and the inverting input terminal of the precision operational amplifier A5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202020961637.8U CN212622387U (en) | 2020-05-29 | 2020-05-29 | Portable electrochemical workstation circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020961637.8U CN212622387U (en) | 2020-05-29 | 2020-05-29 | Portable electrochemical workstation circuit |
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| CN212622387U true CN212622387U (en) | 2021-02-26 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113281386A (en) * | 2021-04-01 | 2021-08-20 | 中山大学 | Multi-channel electrochemical sensor detection device and detection method thereof |
| CN115061523A (en) * | 2022-05-20 | 2022-09-16 | 山西大学 | Portable high-resolution constant potential system |
| CN115575694A (en) * | 2022-12-09 | 2023-01-06 | 阳明量子科技(深圳)有限公司 | Constant potential rectifier capable of detecting micro-current signal |
-
2020
- 2020-05-29 CN CN202020961637.8U patent/CN212622387U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113281386A (en) * | 2021-04-01 | 2021-08-20 | 中山大学 | Multi-channel electrochemical sensor detection device and detection method thereof |
| CN115061523A (en) * | 2022-05-20 | 2022-09-16 | 山西大学 | Portable high-resolution constant potential system |
| CN115575694A (en) * | 2022-12-09 | 2023-01-06 | 阳明量子科技(深圳)有限公司 | Constant potential rectifier capable of detecting micro-current signal |
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