Selectivity enhancement of metal oxide gas sensors using a micromachined gas chromatographic column

For this reason, a highly selective hybrid microsystem based on a gas chromatographic-like (GC) approach is proposed. In this miniaturized gas chromatographic system a solid state gas sensor is used as detector, together with a Silicon micromachined packed GC column, a zero grade air unit, a commercial minipump and a minivalve. With this prototype, Benzene, Toluene and m-Xylene eluted in synthetic or real indoor air were reliably detected and measured at concentrations as low as 5 ppb. The use of chromatographic units together with solid state gas sensors both integrated in silicon allows to develop low-cost, handheld portable devices having exceptional selectivity and reproducibility. Possible applications which could benefit of these performances include security control, air quality monitoring as well as food quality control.