MULTICOMPONENT TRACE-GAS ANALYSIS BY 3 INTRACAVITY PHOTOACOUSTIC CELLS IN A CO LASER - OBSERVATION OF ANAEROBIC AND POSTANAEROBIC EMISSION OF ACETALDEHYDE AND ETHANOL IN CHERRY TOMATOES

Three serial photoacoustic cells are employed within the cavity of a l iquid-nitrogen-cooled CO laser to monitor on-line trace-gas concentrat ions. Multicomponent gas analysis is performed on sequential repetitiv e measurements of ethylene, acetaldehyde, CO2, ethanol, and H2O. To de monstrate the high sensitivity of the laser photoacoustic detector for the biologically interesting gases, acetaldehyde (0.1-parts per billi on in volume detection limit) and ethanol (10 parts per billion ir,vol ume), we follow the time-dependent release by cherry tomatoes during c hanging aerobic-anaerobic conditions. (C) 1998 Optical Society of Amer ica.