Preparation of β-caryophyllene oxidation products and their determination in ambient aerosol samples

Oxidation of beta-caryophyllene with ozone followed by reduction was carried out in dichloromethane. Reaction led to the formation of beta-caryophyllene aldehyde (11%, purity 90.8%) and beta-nocaryophyllone aldehyde (79%, purity 99%). Compounds were purified and separated by liquid-liquid extraction and flash chromatography. Identifications were achieved by electron-impact and electrospray ionization mass spectrometry, and precise structures were confirmed by one and two-dimensional nuclear magnetic resonance spectroscopy. The prepared compounds were used in the analysis of ambient aerosol samples collected during spring 2003 at Hyytiala, Finland. beta-Nocaryophyllone aldehyde was positively identified and quantified in ambient aerosol samples for the first time. The amount of quantified beta-nocaryophyllone aldehyde of aerosol origin was 17.4 +/- 1.0 ng m(-3) of sampled air. Comparison with previous findings led to the conclusion that oxidation products of beta-caryophyllene participate in biogenic aerosol formation over boreal forest during late spring.