I encountered one interesting phenomena, in CV and LSV, the peak current increase with increasing concentration of analyte but the trend is inverse in DPV.
Please see the attach data
Hi, you mean the current of actually decrease with increasing concentration of analyte?
What it means is that when you do CV iTotal=iFaradaic+iCapacitive, whereas when you do DPV iTotal=iFaradaic. So the data for DPV should be more reliable regarding your analysis. From the picture in the document it looks like the analyte lowers the current response of the electrode (at least on an oxidative scan), but maybe you could share a bit more about the electrode, the modifications and the analyte, so that I could tell more...
Hi, thank you for your answer. But from the CV scan, the analyte seem to be oxidize at potential greater 0.7 V. According to some of the publicaiton I read, if the current response in CV increase, the similar trend also will be oberved in DPV. The analyte is nicotine and the modification just metal-polymer nanocomposite.
Hi, in CV / LSV and DPV experiments the current increases with increasing concentration of the analyte, if you have a merely diffusion controlled reaction and no adsorption phenomena are present. However the peak current heights obtained with different methods for the same concentrations of the same analyte cannot be compared directly.The kinetics of the electron transfer play an important role as to the peak appearance obtained in DPV experiments. Since you plot a current difference (ca. 1. derivative) against potential you'll get a smaller and broader peak for slow kinetics than for a rapid electron.
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