Rethinking Data Collection and Signal Processing. 2. Preserving the Temporal Fidelity of Electrochemical Measurements

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• 作者：Christopher W. Atcherley ; Richard F. Vreeland ; Eric B. Monroe ; Esther Sanchez-Gomez ; Michael L. Heien
• 刊名：Analytical Chemistry
• 出版年：2013
• 出版时间：August 20, 2013
• 年：2013
• 卷：85
• 期：16
• 页码：7654-7658
• 全文大小：260K
• 年卷期：v.85,no.16(August 20, 2013)
• ISSN：1520-6882

文摘

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 螖E_peak, 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.