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Characterization and application of porous flow through electrodes in electroanalytical chemistry
Abstract
Reticulated vitreous carbon (RVC) is a relatively new carbon based, rigid porous material. It is produced by the pyrolysis of polyurethane foam at high temperature. It is highly conductive and well suited for use in flow stream electrochemical detectors. Working electrodes constructed from RVC with different pore sizes and geometries were used to explore their working patterns. Depending on the flow rate, two operating modes have been identified: coulometric and amperometric. Some characteristic parameters of these working electrodes have been determined or estimated from which the limiting current equation has been derived for low conversion efficiencies. The equation contains the following three categories of parameters: characteristic parameters of the porous material, geometric factors, and a hydrodynamic variable. One feature is that the limiting current is inversely proportional to the pore size to the two thirds power. The signal-to-noise ratio has been shown to be superior to that of tubular or thin layer electrodes. Porous electrodes are versatile in terms of their design, the key factor being the conversion efficiency, R. The choice of mode of operation is dictated primarily by two considerations: the nature of the application and the signal-to-noise-ratio. The comparison between the porous electrode and tubular and thin layer electrodes was made in terms of the current ratio and the ratio of the signal-to-noise-ratio. The results showed current enhancement and large signal-to-noise-ratio was obtainable using porous electrodes and this in turn suggested that a lower detect limit using porous electrodes is possible. The measurement of the hydrodynamically generated difference current using parallel flow streams was proven to be an effective approach to reject noise and, hence, to obtain low detection limits.
Subject Area
Analytical chemistry
Recommended Citation
Zhu, Caobin, "Characterization and application of porous flow through electrodes in electroanalytical chemistry" (1991). Doctoral Dissertations Available from Proquest. AAI9120964.
https://scholarworks.umass.edu/dissertations/AAI9120964