Classical methods of flavor and fragrance analysis employ a range of techniques for the isolation, concentration and identification of aroma compounds. More recently, interest has grown in the understanding of how aroma compounds interact with and are released from simple and complex foods and cosmetic matrices. It is from these bases that aroma compounds are released in the mouth, for foods, or on the skin or hair for fragrances. Release of volatile components by definition is a kinetic process and has the dimensions of concentration and time.
Flavors and fragrances therefore fit significantly into this temporal environment. How, then, do we manage and monitor the concentration/time dynamics of these complex mixtures of small aroma molecules in the ppbv-ppmv in the gas phase in multifunctional matrices and in timescales from parts of a second to minutes and hours? Additionally, can we measure these fl avor dynamics during the complicated eating process? Classical methods of aroma analysis are limited since they normally require a separation step, usually by gas chromatography, that interrupts the dynamic monitoring process.
The development of chemical ionization techniques, such as proton transfer reaction/mass spectrometry (PTR-MS), has made the continual monitoring of fast formation and release of volatile organic compounds possible.1