In any technique that involves the establishment of a
concentration gradient, either within the material from which an electrode is made or in the solution that
is in contact with an electrode, the bulk concentration of a substance
B is the total or analytical concentration of
B at points so remote from the electrode-solution
interface that the
concentration gradient for
B is indistinguishable from zero at the instant under consideration. In common practice
the bulk concentration of
B is taken to be the total or analytical concentration of
B that would be present throughout the electrode or solution if there were no current
flowing through the cell and if the electrode and solution did not interact in any
way. In the absence of any homogeneous reaction or other process that produces or
consumes
B, the bulk concentration of
B is the total or analytical concentration of
B that is present before the excitation signal is applied.
Source:
PAC, 1985, 57, 1491
(Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations
1985))
on page 1493
