integral capacitance in chromatography

https://dx.doi.org/10.1351/goldbook.I03068
Integral capacitance (per unit area of electrode) is given by
K = Q E − E Q = 0
where Q is the electric charge (per unit area of electrode), E is the potential of the electrode with respect to a reference electrode, and E Q = 0 is the potential at the point of zero charge.
Source:
PAC, 1974, 37, 499 (Electrochemical nomenclature) on page 509