Biosphere dynamics and chemical sensors

• Published in: Sensors and actuators. B, Chemical Vol. 24; no. 1; pp. 162 - 165
• Main Authors: Gutman, E.E., Perov, S.P., Timashev, S.F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.1995
• Subjects: Biosphere dynamics; Chemical sensors; Biosphere dynamics; Chemical sensors
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/0925-4005(95)85035-X

The modern trends of climate modifications and global changes in the biosphere are connected with ‘ozone’ and ‘greenhouse’ problems and with the possible influence on them of hydrogen and different hydrogen-containing particles (H 2O, CH 4, OH). The semiconductor metal oxide based sensors allow the measurement of concentrations and fluxes of practically all H-containing components of interest. The experimental peculiarities of obtaining and selectively detecting OH radicals and H atoms at low pressures and in the presence of other chemically active particles are discussed. The possibilities of the evaluation of a selective and highly sensitive polymer humidity sensor are considered. In addition, a methane semiconductor sensor is proposed. Its selectivity is based upon the spatial separation of the sensing element and the porous catalyst permeable for methane. A differential version of the methane sensor is proposed, containing two sensitive metal oxide layers active with respect to reducing gas detection, one of them being passive with respect to methane detection. The principles of flicker-noise spectroscopy are evaluated for the treatment of temporal sequence of the expected chemical-sensor signals under atmospheric conditions. Such an analysis gives the possibility of obtaining information both about the parameters of the non-stationary atmosphere fluxes and the relaxation processes in the sensor itself.