We purchased two AD5940 Eval boards and tried to use them in an electrochemical sensing application.
To get familiar with the AD5940 device and verify how well it performs in our application, we conducted an experiment using square wave voltammetry in three approaches. a) use a commercial potentiostat (CH); b). Use the Analog Device SensorPal APP; c). Use the Square Wave Voltammetry example code provided here: https://github.com/analogdevicesinc/ad5940-examples
The experiment settings include a glassy carbon electrode, a platinum electrode and a Ag/AgCl electrode, worked as working, counter, reference; 10 mM hexacyanoferrate(ii), PBS 1X.
The configurations applied in the three approaches are shown below:
The results generated from the three approaches are shown below:
From the results shown above, when plotting the current vs index with the data generated from the Square Wave voltammetry example code with the keil project, we do not manage to see a redox peak as we saw from the other approaches.
Can you please explain why it is like this? What might be wrong with what we did in the experiment?
Another question regarding the result generated from SensorPal:
although a redox peak is observed during Square wave voltammetry in the SensorPal, it seems that the peak potential is shifted towards the negative values. Further testing revealed that applying a *-1 factor to both current and potentials gives a similar results as the one obtained from the commercial instrument (CH). Can you please explain why there is such a shift and how to correct it to make sure the visualized potential corresponds to the applied one?