title: Alternating current scanning electrochemical microscopy with simultaneous fast-scan cyclic voltammetry.
abstract: Fast-scan cyclic voltammetry (FSCV) is combined with alternating current scanning electrochemical microscopy (AC-SECM) for simultaneous measurements of impedance and faradaic current. Scan rates of 10-1000 V s(-1) were used for voltammetry, while a high-frequency (100 kHz), low-amplitude (10 mV rms) sine wave was added to the voltammetric waveform for the ac measurement. Both a lock-in amplifier and an analog circuit were used to measure the amplitude of the resultant ac signal. The effect of the added sine wave on the voltammetry at a carbon fiber electrode was investigated and found to have negligible effect. The combined FSCV and ac measurements were used to provide simultaneous chemical and topographical information about a substrate using a single carbon fiber probe. The technique is demonstrated in living cell culture, where cellular respiration and topography were simultaneously imaged without the addition of a redox mediator. This approach promises to be useful for the topographical and multidimensional chemical imaging of substrates.
authors.affiliation: Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, United States.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Koch
authors.forename: Melinda B
authors.initials: MB
authors.lastname: Baur
authors.forename: Erica L
authors.initials: EL
authors.lastname: Woodall
authors.forename: John E
authors.initials: JE
authors.lastname: Baur