DETERMINATION OF PESTICIDES AND POLYCHLORINATED-BIPHENYLS IN WATER - A LOW-SOLVENT METHOD

A tow-solvent method was developed to replace EPA Method 608 for the determination of chlorinated pesticides and polychlorinated biphenyls in water and wastewater. The sample is first passed through large, octadecylsilica, liquid-solid extraction disks; the disks and the particles filtered from the water are then extracted with supercritical carbon dioxide to elute the analytes into a small vial of hexane. Using this method, solvent consumption was reduced by over 90%, and recoveries of at least 80% were obtained for most of the analytes. The extracts were analyzed by gas chromatographic electron-capture mass spectrometry (GC/ECMS), which is particularly sensitive and selective for the quantitation of chlorinated analytes. GC/ECMS also provides unambiguous analyte identification in a single gas chromatographic analysis.