In Situ Gas Generation for Micro Gas Analysis System

This manuscript describes an easy, simple and small system for gas generation. The aim of this work was to establish gas generation for on-site checking or on-site calibration of a micro gas analysis system, microGAS. The new technology, microGAS, achieves real-time measurement of trace level gases in the field. To make the measurement more reliable and convenient, a small gas generation system has been developed. Source reagent solution and generator solution are made to flow by micropumps, mixed in a miniature coil, and then introduced into a microchannel gas desorber. The gas desorber is comprised of a honeycomb-shaped microchannel covered with a thin porous polytetrafluoroethylene membrane. A good generation factor is obtained due to the wide vaporization area and thin solution layer of the microchannel desorber. Generation of H(2)S, SO(2), CH(3)SH and NH(3) gases were examined. Concentrations of the gases are easily controlled by the source reagent concentration and the solution flow rates. At 100 microL min(-1) flow rates for both the source and generator solutions, 30 ppbv to 2 ppmv concentrations are formed with a gas flow rate of 200 mL min(-1). The gas concentration is proportional to the source concentration. The gas generation can be performed only when needed. The gas generation system is combined with microGAS for on-site calibration.