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. The 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 μM (r2=0.999) with a limit of detection (LOD) of 5 μM (S/N=3) and sensitivity of 5.8 pA/μM. Selectivity was further enhanced by employing dual‐electrode detection in the series configuration for detection of species exhibiting chemically reversible redox reactions.