cis-pinic acid, a possible precursor for organic aerosol formation from ozonolysis of α-pinene

A method for the analysis of carboxylic acids in aerosols was developed, based on the collection of particles on Teflon filters (2.5 cm diameter with a 0.4 μm pore size), extraction with dichloromethane, and derivatization with BF 3-methanol followed by analysis of the formed methylesters by large-volume injection GC/MS. In aerosol samples from smog chamber experiments with α-pinene and ozone, this method was applied and resulted in the identification for the first time of cis-pinic acid. Yields were in the range of 1-3% for 1000 pbbv α-pinene reacted with 750 pbbv ozone, and in in the range of 0.3-0.5% for 100 pbbv α-pinene reacted with 75 pbbv ozone. Being a dicarboxylic acid this product is estimated to possess an extremely low vapour pressure and may thus be an important element in gas-to-particle conversion of α-pinene.