Portable instrument for field ready electrochemical experimentation
AssigneeArizona Board of Regents on Behalf of the University of Arizona
InventorsMichael L. Heien, Drew Farrell
Life of this patent
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Abstract
A low-cost, portable potentiostat capable of performing several different electrochemical experiments (e.g. cyclic voltammetry and anodic stripping voltammetry) was designed. The potentiostat runs on one or more batteries and has a battery life of over two weeks. Further, the potentiostat of the present invention is capable of self-calibrating and has a linear dynamic range spanning several orders of magnitude. It is also capable of saving data onto an onboard data storage card and is able to export the data to a computer for additional analysis. The potentiostat requires no peripheral hardware and is suitable for use by those with even minimal training in electrochemistry.
Claims20
A portable potentiostat device (100) effective for decreasing an amount of noise generated in an electrochemical experiment by employing a digital to analog converter (“DAC”) operatively coupled to an analog integrating operational amplifier (108), herein referred to as an integrator, for generating a plurality of increasing and decreasing potentials comprising a potential sweep applied to an analyte during the electrochemical experiment, wherein an analysis and interpretation of a set of experimental data generated by said experiment is performed by the device (100) so that a user, with or without prior knowledge of electrochemistry, is able to execute the electrochemical experiment, the device (100) comprises:
- (a) a potential control module (103) comprising a reference electrode (102) operatively coupled to a counter electrode (104);
- (b) a waveform control module (106) for generating the potential sweep, the waveform control module (106) comprising the DAC (116), an inverter (114) having an input connected to an output of the DAC, a solid state relay (“SSR”) (110) having a first SSR input connected to the output of the DAC and a second SSR input connected to an output of the inverter (114), and the integrator (108) having a first integrator input connected to a first SSR output, a second integrator input connected to a second SSR output, and an integrator output connected to an output of the reference electrode and an input of the counter electrode;
- (c) an electrochemical cell (136) comprising a connection to the reference electrode (102), a connection to the counter electrode (104), and the analyte, wherein the potential sweep is applied to the analyte via the reference electrode (102) and the counter electrode (104);
- (d) a data acquisition module (122) comprising a working electrode (134) operatively coupled to a microcontroller (128), wherein the data acquisition module (122) is operatively coupled to the electrochemical cell (136) via the working electrode (134);
- (e) a user interface (148), operatively coupled to the data acquisition module (122) via the microcontroller (128), providing the user access to the set of experimental data and the analysis and interpretation of said data, wherein the user interface (148) is further configured to allow the user to select a specific electrochemical experiment or run a pre-determined experimental protocol;
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- (f) a power source providing power to the reference electrode (102), the working electrode (134), and the counter electrode (104) thus enabling portability of the device (100),
- wherein each potential in the potential sweep produces an electrochemical effect in the analyte such that a change in potential at the working electrode (134) and a resultant current in the analyte are produced, wherein the set of experimental data comprises, for each potential, the change in potential at the working electrode (134) relative to the potential applied by the reference electrode (102) and a measurement of the resultant current.
A method for performing an electrochemical experiment via a portable potentiostat device effective for decreasing an amount of noise generated in the electrochemical experiment by employing a digital to analog converter (“DAC”) operatively coupled to an analog integrating operational amplifier, herein referred to as an integrator, for generating a plurality of increasing and decreasing potentials comprising a potential sweep applied to an analyte during the electrochemical experiment, wherein an analysis and interpretation of a set of experimental data generated by said experiment is performed by the device so that a user, with or without prior knowledge of electrochemistry, is able to execute the electrochemical experiment, the method comprising:
- (a) providing the portable potentiostat device comprising:
- (i) a potential control module comprising a reference electrode operatively coupled to a counter electrode;
- (ii) a waveform control module (106) for generating the potential sweep, the waveform control module (106) comprising the DAC (116), an inverter (114) having an input connected to an output of the DAC, a solid state relay (“SSR”) (110) having a first SSR input connected to the output of the DAC and a second SSR input connected to an output of the inverter (114), and the integrator (108) having a first integrator input connected to a first SSR output, a second integrator input connected to a second SSR output, and an integrator output connected to an output of the reference electrode and an input of the counter electrode;
- (iii) an electrochemical cell comprising a connection to the reference electrode, a connection to the counter electrode, and the analyte;
- (iv) a data acquisition module comprising a microcontroller operatively coupled to a gain control module comprising a plurality of resistors of various resistance values, wherein the data acquisition module also comprises a working electrode, which couples the gain control module to the electrochemical cell;
- (v) a user interface comprising a touch screen display and a single board computer both operatively coupled to the microcontroller, wherein the single board computer is operatively coupled to the touch screen display;
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- (vi) a power source providing power to the reference electrode, the working electrode, and the counter electrode thus enabling portability of the portable potentiostat device;
- (b) initiating the electrochemical experiment by selecting a type of experiment to be performed via the touch screen, wherein a first selection is anodic stripping voltammetry and a second selection is cyclic voltammetry;
- (c) sending a first signal, indicating the type of experiment to be performed, from the touch screen display to the microcontroller;
- (d) sending a second signal, via the microcontroller, to the waveform control module, wherein the second signal indicates a type of the potential sweep to be generated by the waveform control module based on the type of experiment selected, wherein each potential of the potential sweep is applied across the reference electrode and the working electrode;
- (e) applying the potential sweep to the analyte via the reference electrode and the counter electrode and measuring a resultant current produced by the analyte in response to each potential applied;
- (f) employing an adaptive gain control, wherein when the resultant current exceeds a pre-determined threshold, the microcontroller will send a third signal to the gain control module to switch to a resistor having a lower resistance value than a currently employed resistor, thus changing a gain of the portable potentiostat device and effectively lowering a resultant current to voltage conversion factor;
- (g) performing an analysis of the set of experimental data, comprising each potential applied and an associated resultant current, and generating an interpretation of said data via the single board computer;
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- (h) displaying the set of experimental data, the analysis and interpretation via the touch screen display.
Dependencies are inferred from the claim text.