CARBON-FIBER MICROELECTRODES FOR ADSORPTIVE STRIPPING ANALYSIS OF TRACE NUCLEIC-ACIDS

Carbon fiber ultramicroelectrodes are shown to be suitable for adsorpt ive stripping potentiometric measurements of trace DNA and RNA. The or igin of the carbon fiber has a profound effect upon its suitability fo r trace analysis of nucleic acids, with the 'Aesar' materials performi ng most favorably. The resulting ultramicroelectrodes offer effective adsorptive accumulation of DNA and RNA from unstirred microliter-volum e solutions, and are shown to be useful in adsorptive stripping transf er experiments. The influence of the surface pretreatment and accumula tion conditions is described, along with the analytical-performance ch aracteristics. The detection limits are 6, 15 and 40 mu g/l tRNA, ssDN A and dsDNA, respectively (5 min accumulation). (C) 1998 Elsevier Scie nce S.A.