Figure 1.

A zero-phase IIR Butterworth HPF was applied to the data recorded at each voltage point across the time series, indicated by the horizontal blue lines. The low frequency component of each data set was removed, and only the faradaic current remains. In this illustration, a 1 µM bolus of dopamine in a Tris buffer was injected in a flow cell and the background drift was removed by the filter leaving only the signal due to the presence of dopamine.