COMPARISON OF 2 CLEANUP METHODOLOGIES FOR THE GAS-CHROMATOGRAPHIC MASS-SPECTROMETRIC DETERMINATION OF LOW NANOGRAM GRAM LEVELS OF POLYNUCLEAR AROMATIC-HYDROCARBONS IN SEAFOOD

The March 1989 oil spill in Alaska prompted the Food and Drug Administ ration (FDA) to conduct a thorough investigation of clean-up methodolo gies aimed at determining low ng/g (ppb) levels of polynuclear aromati c hydrocarbons (PAHs) in seafood. The clean-ups from a modified FDA me thod and a National Marine Fisheries Service (NMFS) method were evalua ted on the basis of the determination of 18 PAHs at levels ranging fro m 1 to 5 ppb by gas chromatography/mass spectrometry. In the modified FDA method, seafood extracts were purified by a liquid-liquid partitio n followed by a three-step elution through silica, alumina, and C18 so lid-phase extraction cartridges. In the NMFS method, seafood extracts were purified by column chromatography through a deactivated silica ge l/alumina column and a gel permeation high performance liquid chromato graphy column. Both methods quantitated 18 PAHs at levels ranging from 1 to 5 ppb. With the exception of naphthalene, average recoveries bas ed on internal deuterated standards ranged from 73 to 144% for the mod ified FDA method and 63 to 106% for the NMFS method.