Fully integrated thermal conductivity sensor for gas chromatography without dead volume

A complete detector based on the anemometer principle and sensing the thermal conductivity of gases for application in gas chromatography (GC) will be introduced. The micromachined die contains a reference and a measurement channel. The channels consist of integrated capillary connectors, a measurement chamber, hot-wire elements and elements for thermostatting the bulk. The sensor has been designed to be connected to 100 mu m separation columns and due to novel attachment of the tubing, it has virtually no dead volume. Each measurement chamber has a volume of about 14 nl. The sensing elements are fabricated as gold resistors ant! suspended in the middle of the gas channel. A sturdy and easy-to-handle packaging has been developed. The sensor has been successfully tested in a commercial GC set-up and consumes an approximate power of 0.5 W. (C) 1997 Elsevier Science S.A.