Microchip-Based Analysis Systems: An Undergraduate Laboratory Experiment

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 9 Issue 4 (2004) pp 224-230

Microchip-Based Analysis Systems: An Undergraduate Laboratory Experiment

Matthew K. Hulvey and R. Scott Martin*

Department of Chemistry, Saint Louis University, 3501 Laclede, St. Louis, MO 63103, martinrs@slu.edu
Received April 28, 2004. Accepted June 21, 2004.

Published online: 15 July 2004

Abstract. A new laboratory experiment for instrumental analysis that involves microchip-based analysis systems is described. Students are provided a lithographically-defined master and use it to fabricate a poly(dimethylsiloxane)-based microchip. The flow channel is reversibly sealed over a micromolded carbon electrode and a flow-based amperometric analysis is performed on catechol, a model compound for catecholamine neurotransmitters. The external components of the flow system include a four-port injection valve, a syringe pump, associated tubing, and a computer-controlled potentiostat. The device is evaluated for linearity, limits of detection, calibration sensitivity, and analytical sensitivity. In addition, the effect of flow rate on the amount of peak dispersion in the device is investigated. Instead of the “black box” nature of many current chromatography and flow-analysis systems, the students fabricate a flow-analysis system from raw materials and assemble all of the components of the system. The general approach that is described can be used for different analytes and detection systems and will be of interest to instructors who would like to introduce miniaturized instrumentation, microfluidic principles, and/or flow-based analysis in their courses.

Key Words: Laboratories and Demonstrations; instrumental analysis; analytical chemistry

(*) Corresponding author. (E-mail: martinrs@slu.edu)

Article in PDF format (308 KB) HTML format

Supporting Materials:

The supporting material includes the handout that was given to students performing this experiment in the laboratory portion of instrumental analysis at Saint Louis University. The handout contains an in-depth introduction, experimental details (with diagrams and pictures of the various steps involved), and some sample questions. It is available in a Zip file (230 KB).