Comparative study of a thin-layer cell for analysis of stationary and streaming solutions.
A comparative study with a home-built Kissinger-type twin-electrode thin-layer cell has been made, with the cell either filled with quiescent solutions or used as a flow-through detector. In both modes the cell was polarized by a slow linear potential sweep. The current-voltage curves recorded showed a limiting current region in both cases, in spite of the different types of transport process (steady-state diffusion caused by the redox cycling effect of the counter-electrode in the quiescent solution and convective diffusion in the flowing solution). The sensitivities and also the lower detection limits were found to be nearly the same for the two different modes of operation of the same cell, for which an explanation is given. The main analytical advantage of the thin-layer twin-electrode cell filled with quiescent solution is that only a few mul of analyte solution are necessary for the measurement. It was proved experimentally that this type of cell, used as a flow-through detector, gives the expected limiting current, but this current is dependent on the cube root of the linear flow-rate, in agreement with Weber's theoretical prediction, rather than on the square root of the flow-rate (commonly quoted in the literature).
Farsang
G
G
Institute of Inorganic and Analytical Chemistry of L. Eötvös University, Muzeum krt. 4/B, 1088 Budapest VIII, Hungary.
Dankházi
T
T
Lóránth
J
J
Daruházi
L
L