SELECTIVITY OF ELECTRON-DONOR-BONDED AND ELECTRON-ACCEPTOR-BONDED SILICA PACKING MATERIALS FOR HYDROPHOBIC ENVIRONMENTAL CONTAMINANTS IN POLAR AND NONPOLAR ELUENTS

Electron-acceptor-bonded stationary phases, 2-(nitrophenyl)ethylsilyl (NPE) and 3-(p-nitrophenoxy)propylsilyl (NPO), and electron-donor-bond ed phases, 3-(N-carbazolyl)propylsilyl (CZP), 2-(1-pyrenyl)ethylsilyl (PYE), and 5-coronenylpentylsilyl (COP), were prepared from silica par ticles and their selectivities were examined in both polar and non-pol ar solvents for specific isomers of polychlorodibenzo-p-dioxins (PCDDs ), hexachloronaphthalenes (HxCNs) and planar and non-planar polychloro biphenyl (PCB) congeners, Although no single stationary phase was able to separate all the isomer pairs that are coproduced during the synth esis of the PCDDs and HxCNs, pairs can be separated by selecting a sui table stationary phase and solvent. The separation of mixtures of PCDD isomers were found to be most successful with PYE and NPO phases, whi ch yielded the opposite elution orders for each isomer pair that is pr oduced as a mixture. Similar results were obtained for the HxCN isomer s that were separated on PYE and CZP phases. The COP phase provided ea sier separation of non-ortho-substituted and mono-ortho-substituted PC Bs from the other PCBs based on the planarity than PYE phase. (C) 1997 Elsevier Science B.V.