78 • Reference Section
MultiClamp 700A Theory and Operation, Copyright 2000, 2001 Axon Instruments, Inc.
Amperometry involves voltage clamping the sensor at the oxidation/reduction potential
of the compound of interest while measuring the resultant current. Sudden changes in
the concentration of the compound are registered as blips of current. Amperometry is
typically used for measuring quantal release of electro-active chemicals from vesicles.
The temporal resolution is determined only by the response times of the sensor and the
voltage clamp.
Both cyclic voltammetry and amperometry can be performed by the MultiClamp 700A
without modifications. Such modifications are necessary for some other Axon
amplifiers because electrochemistry typically requires larger voltage commands than is
usual for patch or intracellular recording. However, the MultiClamp 700A was
designed with these larger commands in mind, providing ±1000 mV range.