Pyrolyzed photoresist carbon electrodes for microchip electrophoresis with dual-electrode amperometric detection

The fabrication and evaluation of pyrolyzed photoresist films (PPF) for microchip capillary electrophoresis (CE) with dual-electrode electrochemical (EC) detection is described. ne sensitivity, linearity, and reproducibility were evaluated using catecholamines and related compounds, including dopamine (DA), 5 -hydroxyindole-3-acetic acid (5-HIAA), ascorbic acid (AA), and catechol. Initial studies with DA show the response of the PPF electrodes to be linear between 25 and 500 mu M (r(2) = 0.999) with a limit of detection (LOD) of 5 mu M (S/N = 3) and sensitivity of 5.8 pA/mu M. Selectivity was further enhanced by employing dual-electrode detection in the series configuration for detection of species exhibiting chemically reversible redox reactions.