Development of a novel micropreconcentrator for micro gas chromatography

A novel micropreconcentrator using a simple one-photomask micromachined process is presented. Instead of using E-beam evaporation to deposit metal wires for heaters of micropreconcentrators, a chemical reaction using microfluidic laminar flow patterning was utilized to deposit metal wires as microheater for micropreconcentrators. Metal deposition using this laminar flow patterning technique provides higher deposition rate and easier microfabrication compared to conventional micromachined technologies. In addition to this laminar flow patterning for microheaters, a unique integrated adsorbent forming technique was developed. The aqueous carbohydrate, serving as adsorbents, was filled into the micropreconcentrator and carbonized at a high temperature. The micropreconcentrator can be heated up to 300°C rapidly by applying a constant electrical power of ∼1 W and a heating rate of 10°C/s. Four volatile organic compounds, acetone, benzene, toluene and xylene, were collected through our novel micropreconcentrators and separated by a 17m long gas chromatography column successfully. The peak width at half height (PWHH) of these four compounds were quite narrow (<1.17s) and the minimum PWHH of 0.72s was obtained using acetone.