Synthesis of Molecular Products in Pinene Secondary Organic Aerosol

Abstract The ozonolysis of α-pinene and β-pinene represent substantial global sources of atmospheric secondary organic aerosol (SOA), which plays a pivotal role in climate, air quality, and health. Liquid chromatography/negative electrospray ionization mass spectrometry [LC/(−)ESI-MS] is routinely employed to analyze the molecular composition of pinene SOA; however, the identities of detected molecular products remain largely unvalidated. In this work, we determine the structures of 12 of the most abundant monomeric and dimeric compounds measured using LC/(−)ESI-MS in SOA from α-pinene and β-pinene ozonolysis through independent synthesis of authentic standards, including the extensively studied pinyl-diaterpenyl ester (C17H26O8). This library of standards will enable unambiguous identification and quantification of key molecular markers for pinene SOA in both laboratory-derived and ambient SOA as well as elucidation of their formation and aging mechanisms.