Isomer-Specific Determination of Polychlorinated Naphthalenes in Landfill Leachates by Gas Chromatography/High-Resolution Mass Spectrometry

摘要

As environmental contamination resulting from the release of polychlorinated naphthalenes (PCNs) from landfills is of concern, methods are required to quantify PCNs in landfill leachates. In this study, an isomer-specific analytical method for the determination of PCNs in leachate samples was developed using gas chromatography/high-resolution mass spectrometry. The leachate samples were flocculated and the flocks were extracted using Dean–Stark Soxhlet extraction. The sample extracts were cleaned up automatically using SPD-600GC equipped with a multilayer silica gel column (silica gel/Hsub2/subSOsub4/sub silica gel/AgNOsub3/sub silica gel) and a carbon-dispersed silica gel column. The method achieved PCN recovery rates of 81%–105% with instrument detection limits between 0.05 and 0.1 pg and method detection limits (MDLs) between 0.4 and 4 pg/L for the leachate extracts. The concentrations of PCNs in the leachate samples ranged from less than the MDL to 490 pg/L. The detected PCNs mainly consisted of low-chlorinated components, and the contents of PCNs were reduced following a water treatment process. This analytical method, which is among the most comprehensive isomer-specific methods available for PCNs at present, is based on existing techniques for the quantification of polychlorinated dioxins and furans and thus can be readily adopted by other laboratories.