Fast-scan cyclic voltammetry is an electroanalytical technique commonly used for the detection of neurotransmitters, hormones or metabolites in vitro and in vivo. A carbon microelectrode with a diameter in the lower micrometer range funtions as the probe and is positioned very close to the site under investigation. A triangular voltage signal is applied at high scan rates of typically about 300 V/s and repeated with a frequency of 10 Hz.

The resulting FSCVs can be analyzed by detecting the current peak amplitude on top of a large background. A background subtraction is used to better identify the current peaks. This procedure works well due to the good stability of the background current. The stimulus for the release or uptake of the analyte is synchronized with the recording of the FSCV and is often applied by an external stimulus generator.

The advantages of this technique are its high temporal resolution (millisecond range), its high spatial resolution (lower micrometer range), good specificity (due to distinguishable redox potentials) and sensitivity (nanomolar range) for many analytes.

FSCV_Brain
A carbon microelectrode is positioned on a brain slice to detect neurotransmitters. The applied potential program is illustrated in red and the resulting current response is illustrated in blue. The background of the FSCV is shown as a dotted line.

In PATCHMASTER and POTMASTER the FSCV experiment with synchronized triggering of external stimuli can be set up and customized. Each FSCV is analyzed and the results are displayed in the Analysis Window.

PATCHMASTER software during a FSCV experiment. The Oscilloscope Window shows the current FSCV. The analysis is not shown but can be configured before and after the experiment.
FSCV_w_Background
Raw FSCV data.

The left image shows the raw FSCV data in black and the background FSCV in pink. Due to the high scan rates the background is very large and obscures the small current peaks from dopamine oxidation. The right image shows the background-subtracted peaks.

PATCHMASTER and POTMASTER allow automatic background subtraction.

Dopamin_4_3
Background-subtracted FSCVs.