An amperometric method of end-point location in constant-current coulometry

An amperometric end-point determination for constant-current coulometric titrations has been investigated in which the voltage between two working electrodes having the same polarity with respect to the solution, is kept constant. The two electrodes share the constant current; the lesser fraction of the current through one electrode is recorded—this current being a linear function of the concentration of the ion being determined. An advantage of this method over a conventional amperometric method, is that there is no loss of current efficiency due to electrolysis at the indicator electrode, and consequently the indicating current can be monitored continuously and be very much greater than that used in the conventional method; i.e., end-point detection in titrations involving species that are slowly oxidised or reduced electrochemically under normal amperometric conditions is facilitated.