Thin-layer cell with a rapidly dropping mercury electrode for liquid chromatographic detection

Summary A thin-layer cell with a horizontally positioned, rapidly dropping mercury electrode (TL-RDME) was developed for use in electrochemical detection in liquid chromatography. A specific application to electrosorptive detection based on the measurement of differential doublelayer capacitance, C_d, is detailed. The construction is of both Kel-F and acrylic materials, the latter chosen for ease of viewing. Interchangeable capillaries of varying internal diameter combined with gasket-determined channel thickness allows for a variation in drop times from below 10 ms to more than 200 ms. A drain solution flowing past the reference electrode, which is positioned upstream of the working electrode, provides a convenient electrolyte make-up stream. Typical C_d responses are compared to those obtained using a largevolume wall-jet cell/electrode geometry.