Dear all,
When i plot the peak height vs voltage amplitude or vs voltage step, the curve obtained shows a maximum (may be a narrow plateau) and then decreases.
How to explain the maximum (or narrow plateau) and the decrease after?
In the case of the peak height vs voltage step time the curve obtained is quasi-hyperbolic. is this normal?
What about the peak height curve vs frequency and vs scan rate?
Thanks for helping.
Dear Cornel Radu thank you for your explanations.
Dear Dibakar Pal thank you for your links.
Dear Farid,
In differential pulse voltammetry, the height of the current peak is directly proportional to (1 - exp(-a DE))/(1 + exp(-a DE)) where DE is the voltage pulse amplitude. Therefore, your plot of peak height vs pulse amplitude should be a steeply rising curve followed by a plateau. I am not sure what causes the decrease you observe at very large pulse amplitudes, it may be due to another, irreversible redox system which interferes with the main analytical signal.
Regarding the dependence of peak height on frequency and scan rate, which mode of stripping voltammetry are you referring to? If it is square-wave voltammetry, then the dependence on frequency (f) and scan rate should be the same since the effective scan rate is given by f x DE.
Best wishes
Francois
I agree with Dr Muller and suggest you to go further! You must consider kinetics and mass transport, media condditions and so one...you can find good explanation by reading some books such as Elecrtoanalytical Methods, by Fritz Sholz.
Hope you find your answers! Keep contact!
Dear François L L Muller
Dear Felipe Silva Semaan
Dear Cornel Radu ,
Dear Dibakar
Thank you for your help. I really apreciate.
Until now i have used square wave anodic stripping voltammetry,
I' m sorry that i forgot to mention it. it's clair that this detail was very important.
Dear all,
Now that is done, How to comment the expected curves of the height of the current peak vs the known parameters (voltage amplitude, voltage step, voltage step time and frequency (or scan rate).
are there any formulas that could help?.
Thank you for your responses.
Dear Colleague
Hereby I send you two valuable papers, note that despite the laguage (portuguese), you can find at the website an automatic translation. Both papers are quite complete and comprehensive while talking about SWV and pulse techniques in overall.
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422003000100015
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422004000500019
Good luck!
kindly go through this work you will get worthwhile information:
Article Resolution improvement for anodic stripping signals of lead ...
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