In a potentiometric method of analysis we determine an analyte’s concentration
by measuring the potential of an electrochemical cell under static
conditions. Dynamic techniques, in which current passes through the electrochemical
cell, also are important electrochemical methods of analysis. In
this section we consider coulometry. Voltammetry and amperometry are
covered in section 11D.
Coulometry is based on an exhaustive electrolysis of the analyte. By
exhaustive we mean that the analyte is completely oxidized or reduced at
the working electrode or that it reacts completely with a reagent generated
at the working electrode. There are two forms of coulometry: controlledpotential
coulometry, in which we apply a constant potential to the
electrochemical cell, and controlled-current coulometry, in which
we pass a constant current through the electrochemical cell.