CIS-PINIC ACID, A POSSIBLE PRECURSOR FOR ORGANIC AEROSOL FORMATION FROM OZONOLYSIS OF ALPHA-PINENE

A method for the analysis of carboxylic acids in aerosols was develope d, based on the collection of particles on Teflon filters (2.5 cm diam eter with a 0.4 mu m pore size), extraction with dichloromethane, and derivatization with BF3-methanol followed by analysis of the formed me thylesters by large-volume injection GC/MS. In aerosol samples from sm og chamber experiments with alpha-pinene and ozone, this method was ap plied and resulted in the identification for the first time of cis-pin ic acid. Yields were in the range of 1-3 % for 1000 pbbv alpha-pinene reacted with 750 pbbv ozone, and in in the range of 0.3-0.5% for 100 p bbv alpha-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 alpha-pinene. (C) 1998 Elsevier Science Ltd. All rights reserved.