Dual-column high-performance liquid chromatographic cleanup procedure for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans in fish tissue.

A high-performance liquid chromatographic cleanup procedure employing normal-phase alumina and carbon--silica separations was developed for isolating polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) from other polychlorinated pollutants present in fish tissue. The method utilizes a column-switching step where the dioxins and furans are trace enriched onto a carbon-silica column as they are eluted from the alumina column. Interfering components such as polychlorinated biphenyls and chlorinated diphenyl ethers elute through the carbon--silica column. The PCDDs and PCDFs are subsequently recovered by backflushing the carbon--silica column using toluene.