Hi there
Should the baseline for a square wave voltammetry graph be drawn using the positive or negative potential values? (Positive and negative with respect to the peak potential as given in the difference graph shown below).
The different baselines would obviously result in different current values.
The experiment is of 10 mM ferricyanide/ferrocyanide in PBS(1X, pH 7.4) in a 1:1 molar concentration ratio. 0.6 V to -0.4 V @ 25 Hz, 25 mV Pulse size, 5 mV step size.
Kind regards
Riaan
Baselines are drawn from the leading edge, whether that is positive or negative of the peak depends on your scan direction. Note that if you can run a "blank" and subtract that out, that often gives a better value than creating a baseline with a linear fit. This is particularly true if you've got a wavy background due either to noise or electrode characteristics (e.g. carbon electrodes have a background that includes redox features).
Hi,
The one before the peak. Another possibility is the line that joins the peak starting and peak end.
The best measurement as Jacob said is using the line corresponding to the background. You should do the background first and overlay both graphs and see how accurate the measurement is. In any case, maintain for the study the same criterium, in order to consider reliable the study.
Good luck!
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