Theoretical treatment of intermediate electrolysis electrochemical detectors

A simple approach for deriving expressions for the limiting steady-state response of the open tubular electrode, under conditions of intermediate electrolytic yields, is described. This approach couples the principles of laminar fluid dynamics with the theory of the porous electrode reactor. The dependence of the limiting current, I₁, on flow rate, V_f, has the form of I₁ α V^m_f , with m ? $\text{1}\text{3}$, depending upon the electrolytic yield. The effects of electroactive species depletion upon the detector response are discussed. Experimental results are incorporated to support the theoretical conclusions. For a tubular electrode (4-cm long) the degree of conversion decreases from 0.21 to 0.03 and m decreases from 0.42 to 0.32 as the flow rate increases from 0.15 to 3.5 ml min^-1.