An expanded characterization of an open-tubular liquid chromatographic system using a 15-µm i.d. reversed-phase column and an on-column electrochemical detector is presented. The decline in reversibility of catechol oxidation in acetate buffer compared to phosphate buffer upon repeat potential sweeps is examined. An electrochemical cleaning procedure is described that reverses the electrode fouling occurring in acetate buffer and removes adsorbed products from phenol oxidation. A comparison of detection limits for acetaminophen oxidation by a d.c. amperometric mode vs. a differential pulse mode is given. Detection in a reductive mode is also examined. Finally, preliminary results from an 8-µm i.d. reversed-phase column using a 5-µm diameter, graphite fiber, working electrode are presented.