SELECTIVE ELECTROCHEMICAL DETECTION USING A SPLIT DISK ARRAY ELECTRODE IN A THIN-LAYER RADIAL FLOW SYSTEM

An eight-sector array (split disk) electrode was designed for a low no w rate (< 100 mu L/min) amperometric detector, This electrode was fabr icated photolithographically for dimensional accuracy and reproducibil ity. This array of a pie-shaped electrode was combined with a thin-lay er radial now cell, and a conversion efficiency of 94% was achieved at the lowest now rate tested (0.01 mL/min). Each electrode worked free from the effects of electrochemical reactions of the other electrodes. A coulometric hydrodynamic voltammogram of reversible redox species o btained using this system exhibited a Nernstian curve, These propertie s enabled this electrochemical detector to be used for determining the ratio of two redox species (redox potential difference approximate to 100 mV) with small injection volume (5 mu L).