Follow your nose - Traveling the world of odorants in new cars.

Volatile organic compounds of the vehicle interior are well investigated, but only limited information is available on the odorants of the passenger cabin. To close this gap, we aimed at specifically elucidating the odor, as a general proof of principle, of two new cars with different seat upholstery in a controlled environment using a targeted odorant analysis. In a first step, odor profiles were evaluated by a descriptive sensory analysis. Then, potent odorants of the passenger cabins were characterized by gas chromatography-olfactometry and ranked according to their odor potency via odor extract dilution analysis. Using this approach, 41 potent odorants were detected, and 39 odorants were successfully identified by two-dimensional gas chromatography-mass spectrometry/olfactometry. In a third step, important odorants of the vehicle interior were quantified by means of internal standard addition. The most dominant odorants could be assigned to several specific substance classes comprising esters, saturated and unsaturated aldehydes, unsaturated ketones, rose ketones, phenolic and benzene derivatives, and pyrazines, occurring in a concentration range between 0.05 and 219 ng/L in air. Of these potent odorants, the aldehydes 2-butylhept-2-enal, 2-propyloct-2-enal, and (Z)-2-butyloct-2-enal are reported here for the first time as odorants in the environment of a passenger cabin.