ISOMER-SPECIFIC DETERMINATION OF 79 POLYCHLORINATED DIPHENYL ETHERS (PCDE) IN COD-LIVER OILS, CHLOROPHENOLS AND IN A FLY ASH

The occurrence of polychlorinated diphenyl ethers (PCDEs) has been inv estigated in two different cod liver oils produced in 1985 and 1993, r espectively, from North-Atlantic fish. These samples mirror the distri bution of PCDEs among other persistent organochlorine compounds in the marine environment. To elucidate the input of PCDEs in the environmen t, five possible sources of PCDEs have been analyzed, namely two wood preserving formulations containing approximately 10% pentachlorophenol , two technical chlorophenol products, and one fly ash from a municipa l waste incinerator. The determination has been based on 106 available PCDE congeners. During sample preparation a 2-(1-pyrenyl)ethyldimethy lsilylated silica column has been used in the normal phase mode to sep arate the PCDEs from possible PCDF interferences. The PCDEs have been quantified by high resolution gas chromatography/mass spectrometry on a SE 54 capillary column using electron ionization and selected ion mo nitoring. The total amount of PCDEs in 2,3,4,6-tetrachlorophenol have been determined to be 213 mg/kg. The lowest concentrations of PCDEs ha ve been found in the more recently produced cod liver oil (sum PCDEs: 49 mu g/kg) and in the fly ash sample (sum PCDEs: 93 mu g/kg), respect ively. The isomer-specific analysis has been employed to characterize the relationship between possible sources and the PCDEs found in the e nvironment. PCDEs, like PCBs, can be indicator molecules for the globa l pollution of the environment.