INTERDIGITATED ARRAY ELECTRODE - A SENSOR FOR TRACE ELECTROANALYSIS

A method applying an interdigitated array (IDA) microelectrode is prop osed for the determination of traces of Fe in ultrapure spectral carbo n. Its adjacent microbands are polarized by the different potentials ( generator -0.7 V and collector -0.3 V vs. SCE). Redox cycling leads to a substantial current enhancement. Time integration of the collector current is used for the quantitation. The method was tested using synt hetic samples containing Fe at the trace level required for the high p urity spectral carbons (10(-5) wt % Fe). It was applied for Fe analysi s in some real samples - commercially available spectral rods.