As a result of the rapid development within the field of lab-on-a-chip systems, there is currently a growing interest in miniaturised electrochemical devices. This can be explained by the fact that electrochemical devices can be readily miniaturised and that the required electrodes can be manufactured with standard microfabrication techniques. Electrochemically controlled solid-phase microextraction, employing electronically conducting polymers, is a new promising sample pretreatment technique [1-3]. As the extraction and desorption of analytes is controlled merely by the potential of the conducting polymer, this technique is highly suitable for inclusion in miniaturised chip-based systems. By use of electrochemical detection in capillary electrophoresis, employing e.g. arrays of microfabricated electrodes [4, 5], both efficient chip-based separations and low detection limits can be obtained even for complex samples.
This presentation will focus on our recent research aiming at the development of electrochemical techniques for chip-based sample preparation and detection. It will be demonstrated that electrochemically controlled solid phase extraction can be used for straightforward sample preparation and significant sample preconcentration. It will also be shown that electrochemical detection in capillary electrophoresis can be performed without interferences from the capillary electrophoretic electric field. A novel potentiostatless electrochemical detection technique based on the utilisation of the capillary electrophoretic electric field will likewise be described.
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