Determination of volatile and semivolatile mutagens in air using solid absorbents and supercritical fluid extraction

Volatile toxicants may be present in emissions from mobile and stationary sources as well as in ambient air. Methods for collecting and concentrating volatiles from air samples have been developed. Solid-phase adsorbents were compared in their trapping efficiencies for dichloromethane (DCM), ethylene dibromide (EDB), 4-nitroblphenyl (4-NB), 2-nitrofluorene (2-NF), and fluoranthene (FI). Charcoal and Carbosieve were the most efficient media for retaining DCM, while XAD-4 was the best adsorbent for EDB and the aromatic compounds. Extraction of direct spikes of compounds from adsorbents using supercritical carbon dioxide resulted in greater than 90% recovery of EDB and 60-92% recovery of the aromatics. Integration of trapping and desorption methods with the Salmonella microsuspension bioassay was demonstrated with EDB and 4-NB recoveries from air; chemical analysis and bioassay gave comparable results (within 10%).