A novel method for characterizing polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic compounds (PACs) in the environment

Mary Elizabeth Lee
California State University, Los Angeles

Nonpolar polycyclic aromatic hydrocarbons (PAHs) react with sunlight to produce polycyclic aromatic compounds (PACs) which are readily transported through aqueous media including watersheds, plants, and animals. These compounds are of significant concern due to their ubiquity, environmental persistence, and toxicities. Previous detection methods used for identifying trace levels of PAHs and PACs have been limited by their sensitivity and selectivity. Here we present a new technique, APCI/MS/MS, which provides unparalleled selectivity and outstanding sensitivity for both PAH and PAC compounds. We discuss results of a photolysis study of the PAH benzo[a]pyrene (B[a]P) on silica, which was conducted in order to quantify B[a]P degradation and B[a]P-photoproduct formation as functions of irradiance time using HPLC/PDA and APCI-MS/MS independently. Both detection techniques identified B[a]P and its photoproduct in irradiated samples, indicating that each is capable of monitoring the photo-oxidative activity of B[a]P. The combination of these techniques will provide an even greater tool toward understanding the chemical transformations and transportation of PAHs and PACs in the environment.