Small-volume electrochemical detector for microcolumn liquid chromatography

Flow rate independent amperometric cell

“…where I is the convection dependent current, We is the width of the electrode, L is the length of the electrode, b is the spacer thickness, U is the average volume flow rate, and Wc is the width of the channel. In a previous paper, we found this equation to be valid at carbon electrodes (21). However, this equation predicts that the current will approach zero as the flow rate approaches zero and, thus, it ignores the convection independent, steady-state contribution of an electrode with a small area.…”

Electrochemical Detection Methods for Monoamine Measurements in Vitro and in Vivo

“…The ideal situation is an electrode system that is compatible with gradient chromatography, as this would greatly extend the range of substances that could be detected in a single run. The advent of microchromatographic columns has been paralleled by the development of a microdetector cell (Hirata et at., 1980). It has already been indicated that several "minor" amines are electroactive and assay techniques have been developed for some; these include tryptamine (Marsden et at., 1981) and pineal melatonin (Goldman et at., 1980;, as well as methods for tetrahydroisoquinoline derivatives (Collins et at., 1979;McMurtrey et at., 1980) and catechol estrogens (Goodale and Van Orden, 1978;Shimada et at., 1979).…”

Development of capillary liquid chromatography: A personal perspective

“…columns by Scott and Kucera [53] and with open tubular LC by Ishii et al [35] using a UV-absorbance detector. Similar considerations were certainly valid for on-column fluorescence [54, 55] and electrochemical detection [56]. Most often, an optical cell could be created through a careful removal of a polymeric coat of the fused silica capillaries, which researchers had to perform painstakingly on their modified home-made detectors.…”