High-performance liquid chromatographic determination of azaarenes and their metabolites in groundwater affected by creosote wood preservatives.

Polynuclear azaheterocyclic compounds (azaarenes) are nitrogen-containing analogs of polycyclic aromatic hydrocarbons (PAHs). The nitrogen atom in the ring system causes these compounds to be slightly polar and considerably more water soluble than related PAHs. A method using a solid-surface sorption technique to extract and concentrate azaarenes and their principle metabolites present in groundwater that contains creosote waste is described. Analyte isolation and concentration is accomplished by solid-phase extraction on n-octadecyl cartridges followed by instrumental determination involving high-performance liquid chromatography. Separations and detection are achieved using flexible-walled, wide-bore columns with ultraviolet and fluorescence photometric detectors connected in series. Fluorescence detection alone is insufficient because the fluorescence response produced by two-ring azaarenes is limited. Short wavelength (229 nm) absorbance detection provides improved sensitivity for these compounds and peak rationing for more definitive identification. In this study, oxygen-containing metabolites of quinoline, isoquinoline, and acridine are detected in groundwater from hazardous waste sites in Pensacola, Florida and St. Louis Park, Minnesota. Concentrations ranging from mg/L to ng/L are measured. The dependence of measured octanol-water partition coefficients on pH is discussed in the context of the isolation chemistry. As a direct bacterial degradation product of acridine with a relatively long environmental persistence, 9-acridinone may serve as a biogenic marker signaling creosote contamination of groundwater.