Equation relating limiting current at a rotating disc electrode (see hydrodynamic voltammetry) to the amount concentration of an electroactive substance in bulk solution \(c_{0}\), \[I_{\rm{lim}} = k\,z\,F\,A\,D^{2/3} \omega^{1/2} \nu^{−1/6} c_{0}\] where \(k\) is a numerical factor, \(z\) the electron number of an electrochemical reaction, \(F\) the Faraday constant, \(A\) the electrode surface area, \(D\) the diffusion coefficient of the electroactive substance, \(\omega\) the angular velocity (rotation rate), and \(\nu\) the kinematic viscosity of the solution.