Multicomponent trace-gas analysis by three 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 liquid-nitrogen-cooled CO laser to monitor on-line trace-gas concentrations. Multicomponent gas analysis is performed on sequential repetitive measurements of ethylene, acetaldehyde, CO2, ethanol, and H2O. To demonstrate the high sensitivity of the laser photoacoustic detector for the biologically interesting gases, acetaldehyde (0.1-parts per billion in volume detection limit) and ethanol (10 parts per billion in volume), we follow the time-dependent release by cherry tomatoes during changing aerobic-anaerobic conditions.