Method and apparatus for assay of electrochemical properties
View Patent ↗A method for monitoring a select analyte in a sample in an electrochemical system. The method includes applying to the electrochemical system a time-varying potential superimposed on a DC potential to generate a signal; and discerning from the signal a contribution from the select analyte by resolving an estimation equation based on a Faradaic signal component and a nonfaradaic signal component.
1. A method for determining the extent of electrode fouling in an implantable electrochemical sensor comprising at least two electrodes, said method comprising:
applying a potential stimulus to the electrodes to generate a current signal, the potential stimulus comprising a time-varying potential component superimposed on a constant potential component;
isolating a time-varying current component from the current signal;
determining an imaginary part of the time-varying current component, the magnitude of the imaginary part of the time-varying current component being linearly related to the effective electrode area; and
determining the extent of electrode fouling from the determined magnitude of the imaginary part of the time-varying current component.
2. The method of claim 1 , further comprising determining a change in effective electrode area as a result of electrode fouling.
3. The method of claim 2 , further comprising adjusting a determination of concentration of an analyte based on the change in effective electrode area.
4. The method of claim 3 , wherein the adjustment corrects for a decrease in signal intensity due to fouling.
5. The method of claim 3 , wherein the adjustment is based on relative changes from initial analyte estimates.
6. The method of claim 3 , wherein the adjustment is based on reference to an external data source.
7. The method of claim 6 , wherein the external data source comprises one or more calibration curves.
8. The method of claim 7 , wherein the calibration curves comprise calibration data gathered from electrodes having different electrode areas.
9. The method of claim 2 , further comprising correcting for signal distortion caused by changes in the effective electrode area.
10. The method of claim 1 , further comprising adjusting a measured current signal based on the determined extent of electrode fouling.
11. The method of claim 1 , further comprising correcting for signal distortion resulting from electrode fouling based on the extent of electrode fouling.