Micro gas analysis system for measurement of atmospheric hydrogen sulfide and sulfur dioxide

Abstract

A honeycomb structure microchannel scrubber was developed to achieve efficient and stable gas collection. A thin porous membrane was pasted on a microchannel by the adhesive force of a fresh polydimethylsiloxane surface. The microchannel scrubber achieved much more efficient gas collection than conventional impingers and diffusion scrubbers. Two sets of the microchannel scrubbers and detectors were integrated in a 10 cm × 9 cm plastic board to create a micro gas analysis system (μGAS) for simultaneous measurements of H₂S and SO₂. The whole system including a battery was incorporated in a carrying case 34 cm W × 16 cm D × 17 cm H for use in the field. Liquid flows at 30 µl min⁻¹ were obtained by bimetal micropumps. The estimated detection limits were 0.1 ppbv for H₂S and 1 ppbv for SO₂. The system was demonstrated for real atmospheric gas analysis, and the results agreed well with data concurrently obtained by ion chromatography coupled with a cylindrical diffusion scrubber. The system we developed allowed automated continuous analyses in the field and achieved a much higher time resolution compared to those by ion chromatographic analysis.