title: Rethinking data collection and signal processing. 2. Preserving the temporal fidelity of electrochemical measurements.
abstract: 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.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Atcherley
authors.forename: Richard F
authors.initials: RF
authors.lastname: Vreeland
authors.forename: Eric B
authors.initials: EB
authors.lastname: Monroe
authors.forename: Esther
authors.initials: E
authors.lastname: Sanchez-Gomez
authors.forename: Michael L
authors.initials: ML
authors.lastname: Heien
mesh_terms: D000818:Animals; D003625:Data Collection; D055664:Electrochemical Techniques / Q000592:standards*; D005089:Exocytosis; D005583:Fourier Analysis; D007700:Kinetics; D016716:PC12 Cells; D051381:Rats; D012815:Signal Processing, Computer-Assisted