Mobile laser photoacoustic spectrometer for multicomponent trace-gas monitoring based on CO/sub 2/- and quantum-cascade lasers as pump sources

Abstract

Summary form only given. The development and application of a mobile laser-photoacoustic spectrometer for in-situ multicomponent monitoring of trace gases in different environments is reported. Sub-ppbV (<10/sup -9/ per volume)-concentrations can be measured with a novel resonant multipass photoacoustic cell. For ethene (C/sub 2/H/sub 4/) buffered in synthetic air a minimum detection limit of 70 pptV (70/spl times/10/sup -12/ per volume) is achieved with a line-tunable CO/sub 2/-laser as pump source corresponding to a minimum measurable absorption coefficient /spl alpha//sub min/=2/spl times/10/sup -9/ cm/sup -1/ for a signal-to-noise ratio of 3. The multicomponent capability of the system is demonstrated with continuous sequential measurements of gases such as ethene, methanol, and ethanol of air from a fruit storage chamber.