Rapid method for determination of dioxin-like polychlorinated biphenyls and other congeners in marine sediments using sonic extraction and photodiode array detection

A rapid method has been developed to measure dioxin-like polychlorinated biphenyl (PCB) congeners as well as other selected PCBs in sediment. The analytes were extracted from sediment by sonication with dichloromethane, and the PCBs were separated from interfering compounds on a gravity-flow cleanup column packed with acidic, basic, and neutral silica gels eluted with 1:1 hexane:pentane (v/v). Subsequently, the dioxin-like PCB congeners were resolved from nonplanar PCBs and other chlorinated compounds by high-performance liquid chromatography (HPLC). Two important advantages of PDA over conventional UV detection are the ability to identify individual analytes by comparing their UV spectra with those of reference standards and the ability to establish the spectral homogeneity (purity) of the analytes by comparing spectra within a peak to the apex spectrum. The HPLC-PDA method was tested with reference and marine sediment samples. Concentrations of selected dioxin-like PCBs, selected nonplanar PCBs, and summed PCBs in sediments and National Institute of Standards and Technology standard reference materials determined by our rapid HPLC-PDA method were comparable with the levels in the same samples analyzed by alternative comprehensive methods (i.e., gas chromatography-electron capture detection or high-resolution gas chromatography-high-resolution mass spectrometry).