Micro-gas analysis system (mu)GAS comprising a microchannel scrubber and a micro-fluorescence detector for measurement of hydrogen sulfide

A micro-gas analysis system, (mu)GAS, is proposed here for the continuous and highly sensitive on-site measurement of atmospheric trace gases. The (mu)GAS presented here is comprised of a microchannel scrubber and a high-sensitivity small fluorescence detector. The key to the (mu)GAS is the fabrication of a good gas permeable membrane on a shallow channel to allow for the efficient accumulation of the analyte into the absorbing solution. The channel is formed by micromachining, and a gas permeable membrane of any desired thickness is formed by spin-coating on a fluorosilane-treated substrate. In this work, polydimethylsiloxane was used for both the channel block and the gas permeable membrane, and were easily tightly bonded. The microchannel structure ensures a high sensitivity, and the sensitivity is inversely proportional to the membrane thickness. The device, including the air supply function, is set in only 30-mm-cube. The performance of the (mu)GAS has been demonstrated as a H2S gas sensor. The (mu)GAS consumes only 1 ml of the reagent solution in 8 h of operation with a detection limit of 1 ppbv.