Microfluidic system for the integration and cyclic operation of gas sensors

This article describes a microfluidic system for the detection of gases. Di fferent flow channels, each to be controlled by a microvalve, lead to chamb ers where thin film gas sensors have been integrated. This system is intend ed for alleviating the problems of microstructured thin film gas sensors su ch as cross-sensitivity, slow saturation of the sensor signal and baseline drift. With the microfluidic system presented, these problems may be overco me by a cyclic operation of the gas sensors with each cycle leading through subsequent processes of purging, calibration and measurement. All system c omponents were fabricated using silicon micromachining technologies includi ng the gas sensors integrated into the system. Preliminary measurements on such microchamber gas sensors are presented. (C) 1999 Elsevier Science S.A. All rights reserved.