Abstract

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^-9 per volume)-concentrations can be measured with a novel resonant multipass photoacoustic cell [1]. For ethene (C₂H₄) buffered in synthetic air a minimum detection limit of 70 pptV (70×10^-12 per volume) is achieved with a line-tunable CO₂-laser as pump source corresponding to a minimum measurable absorption coefficient α_min = 2×10^-9cm^-1 for a signalto-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 as shown in Fig. 1.

© 2000 IEEE