RAPID-DETERMINATION OF POLYAROMATIC HYDROCARBONS AND POLYCHLORINATED-BIPHENYLS IN WATER USING SOLID-PHASE MICROEXTRACTION AND GCMS

Solid-phase microextraction (SPME) was investigated as a solvent-free alternative method for the extraction and analysis of nonpolar semivolatile analytes. Analytes were extracted into a polymeric phase immobilized onto a fused-silica fiber. The fiber was then inserted directly into the injector of a gas chromatograph, and the analytes were thermally desorbed. This new technique allows sampling directly from the source (lake, drinking fountain, etc.) and, therefore, eliminates the loss of analytes through adsorption onto container walls and saves transport costs. Using a 15-mum poly(dimethylsiloxane) or a Carbopack B coating and an ion trap mass spectrometer, detection limits-ranging from 1 to 20 pg/mL were obtained for naphthalene, anthracene, benz[a]anthracene, benz[a]pyrene, 2,2',5-trichlorbiphenyl, and 2,2',3,4,5'-pentachlorbiphenyl after only a 10-min sampling time. The detection limits obtained exceed the regulatory requirements of U.S. Environmental Protection Agency (U.S. EPA) method 525. Linearity extended from low picogram per milliliter to nanogram per milliliter levels for all of the compounds studied. The relative standard deviation was comparable with U.S. EPA method 525, ranging from 10% for the polyaromatic hydrocarbons (PAH) to 20% for the polychlorinated biphenyl (PCB). Initial experimental data demonstrate that SPME can be used to quantitatively determine nonpolar semivolatiles in clean aqueous matrices and as a screening tool for wastewaters.