Improving data acquisition for fast scan cyclic voltammetry

Described is an improved data acquisition system for fast-scan cyclic volta mmetry (FSCV). The system was designed to significantly diminish noise sour ces that were identified in previously recorded FSCV measurements for the d etection of neurotransmitters. Minimized noise is necessary to observe the low concentrations of neurotransmitters that are physiologically important. The system was based on a high-speed, 16-bit AD/DA acquisition board that allowed high scan rates and better resolved the small faradaic currents whi ch remained after background subtraction. Irregularities that occur when in dependent timing sources are used for generation of the voltage waveform an d collection of the current can create large noise artifacts near the volta ge limits during FSCV. These were eliminated by the use of a single acquisi tion board that generated the voltage waveform and collected the current. N oise from frequency drift of the power line was eliminated through the use of a phase-locked loop. To demonstrate the improved performance of the syst em, data were collected using carbon-fiber microelectrodes in a flow inject ion analysis system and in brain slices. This new data acquisition system p erformed significantly better than another system previously used in our la boratory without these features. The improved detection limits of the new s ystem allowed clearly resolved current spikes featuring pre-release "feet" to be recorded adjacent to individual mast cells following chemical stimula tion. When combined with false-color plots, the low-noise system facilitate d identification of dopamine release in a freely moving animal.