Direct electrochemical measurements of biological events are often challenging because of the low signal relative to the magnitude of the background and noise. When choosing a data processing approach, the frequency and phase content of the data must be considered. Here, we employ a zero-phase (infinite impulse response (IIR)) filter to remove the noise from the analytical signal, while preserving the phase content. In fast-scan cyclic voltammetry, the frequency content of the signal is a function of the scan rate of the applied waveform. Fourier analysis was used to develop a relationship between scan rate and the filter cutoff frequency to maximize the reduction in noise, while not altering the true nature of the analytical signal. The zero-phase filter has the same effect as traditional filters with regards to increasing the signal-to-noise ratio. Because the zero-phase filter does not introduce a change to ΔEpeak, the heterogeneous electron rate transfer constant (0.10 cm/s) for ferrocene is calculated accurately. The zero-phase filter also improves electrochemical analysis of signaling molecules that have their oxidation potential close to the switching potential. Lastly, a quantitative approach to filtering amperometric traces of exocytosis based on the rise time was developed.
ASJC Scopus subject areas
- Analytical Chemistry