M. Nagele et Mw. Sigrist, Mobile laser spectrometer with novel resonant multipass photoacoustic cellfor trace-gas sensing, APP PHYS B, 70(6), 2000, pp. 895-901
The development and application of a mobile laser-photoacoustic spectromete
r for in situ multicomponent monitoring of trace gases in different environ
ments is reported. Sub-ppbV (< 10(-9) per volume)-concentrations can be mea
sured with a novel resonant multipass photoacoustic cell. The cell is desig
ned for flow mode operation in order to reduce adsorption effects. For ethe
ne (C2H4) buffered in synthetic air a minimum detection limit of 70 ppt V (
70 x 10(-12) per volume) is achieved corresponding to a minimum measurable
absorption coefficient alpha(min) = 2 x 10(-9) cm(-1) for a signal-to-noise
ratio of 3. The multicomponent capability of the system is demonstrated wi
th continuous sequential measurements of ethene, methanol, ethanol, CO2, an
d H2O of air from a fruit storage chamber.