High-resolution gas chromatography retention data as basis for the estimation of KOW values using PCB congeners as secondary standards

We estimated K-OW values that are usually derived by liquid chromatography solely from gas chromatographic (GC) data by selective correlation with PCB congeners as secondary standards. The GC method was established and validated with literature-known values obtained with other methods. Twenty-seven chlorinated diphenyl ethers (PCDE), 19 chlorinated naphthalenes (PCN), 4,4'-DDE, and three brominated diphenyl ethers (PBDE) were used for method validation. The advantages of our method are that only amounts in the nanogram range or less are needed, complex mixtures can be analyzed, K-OW values of isomers can be determined, and even the exact structure of compounds does not have to be known. The quality of the K-OW values obtained by the GC method mainly depends on the accuracy of the data of the compounds used as standards for the correlation. These data should be based on reliable experimental methods. Our semi-experimental approach in approximating physicochemical data relevant to the environmental distribution-vapor pressure of subcooled liquid and log K-OW-can be extended to further classes of compounds because normalized GC retention data are easily available. We exemplified our approach with a bioaccumulating naturally occurring hepta chlorinated 1-methyl-1',2-bipyrrole, which is highly abundant in fish from the South Atlantic among others.