Electrochemical Detection in Polymer Microchannels

• Published in: Analytical chemistry (Washington) Vol. 71; no. 19; pp. 4294 - 4299
• Main Authors: Rossier, J. S, Roberts, M. A, Ferrigno, R, Girault, H. H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.10.1999
• Subjects: Analytical chemistry; Chemistry; Electrochemical methods; Exact sciences and technology; Instruments; Polymers; Performance evaluation; Cyclic voltammetry; Electrode production; Analysis method; Strip electrode; Electrochemical method; Carbon electrode; Geometrical configuration; Laser ablation technique; Microminiaturization; Chronoamperometry; Electrical characteristic
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac981382i

A method, using UV laser photoablation, is presented for the fabrication and the integration of an electrochemical detector in a microchannel device, where carbon microband electrodes are placed either in the bottom or in the side walls of the rectangular microchannel. The different electrochemical cell geometries are tested with a model compound (ferrocenecarboxylic acid) in 40- and 100-μm-wide capillaries fabricated in planar polymer substrates. The experimental results are compared to numerical simulations for stagnant stream conditions. Depending on the scan rate and on the microchannel depth, the system behaves as a microband electrode until a linear diffusion field develops within the channel. The limit of detection for a one electron redox species within the 120-pL detection volume is ∼1 fmol with both cyclic voltammetry and chronoamperometric detection.