Micromachined Electrophoresis Chips with Thick-Film Electrochemical Detectors

Joseph Wang,* Baomin Tian, and Eskil Sahlin
Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003
Anal. Chem., 1999, 71 (23), pp 5436–5440
DOI: 10.1021/ac990807d
Publication Date (Web): October 29, 1999
Copyright © 1999 American Chemical Society
*

 Corresponding author:  (phone) 505-646-2140; (fax) 505-646-6033; (e-mail) joewang@nmsu.edu.

Abstract

A capillary electrophoresis (CE) microsystem, based on the combination of microphotolithographically fabricated separation chips and thick-film electrochemical detector strips, is described. The microsystem consists of a planar screen-printed carbon line electrode mounted perpendicular to the flow direction. Such coupling obviates the need for permanent attachment of the detector, to allow easy and fast replacement of the working electrode. Variables influencing the separation efficiency and amperometric response, including the channel−electrode spacing, separation voltage, or detection potential, are assessed and optimized. The versatility, simplicity, and low-cost advantages of the new design are coupled to an attractive performance, with submicromolar detection limits, and good precision. Applicability for assays of mixtures of nitroaromatic explosives or catecholamines is demonstrated. Such use of screen-printed detectors should also benefit conventional CE systems, particularly in applications requiring a frequent replacement of the working electrode.

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History

  • Published In Issue December 01, 1999
  • Received for review July 21, 1999. Accepted September 21, 1999.

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