The application of thermal desorption GC/MS with simultaneous olfactory evaluation for the characterization and quantification of odor compounds from a dairy

Few analytical methods exist that combine chemical and sensory analysis of odorous compounds in whole air. Volatile organic compounds were collected by sampling air downwind from a small dairy through sorbent-tubes of Tenax TA and Carboxen 569. Samples were analyzed by thermal desorption into a cryotrap and subsequent as:chromatographic separation, followed by simultaneous olfactometry and mass spectrometry. Because compounds are concentrated during sampling, sensory analysis encountered compounds at a concentration 40 times that in air, making this a useful method for identifying trace compounds participating in odor. Twenty odorous and nonodorous compounds were identified and quantified, including straight-chain and aromatic. hydrocarbons, chlorinated compounds, alcohols, ketones, aldeydes, and organic acids, at air concentrations of 0.55=320.20 mug/m(3). Compound peaks were characterized by odors ranging from offensive I to pleasant, demonstrating the integrative nature-of olfaction. This method could be useful in studying many kinds of odors in air.