Separation of closely eluting chloronaphthalene congeners by two-dimensional gas chromatography/quadrupole mass spectrometry: An advanced tool in the study and risk analysis of dioxin-like chloronaphthalenes

Two capillary columns of different polarity were applied in a two-dimensional gas chromatography system coupled to a quadrupole mass spectrometric detection (GC x GC/qMS) in order to separate and identify all of the possible 22 isomers of tetra-, 14 of penta- and 10 of hexachloronaphthalene that may occur in selected industrial chemicals. The two-dimensional GC x GC separation was achieved using Rt-β DEXcst and DB-WAX phases, and data imaging was done by 2D and 3D mapping. This combination allows for the analysis of all tetra- to hexachloronaphthalene congeners in a single instrumental run without any pre-separation or fractionation of the analytes. The novel methodology described here can assist in the accurate determination and expression of dioxin-like toxicity of tetrachloronaphthalenes to octachloronaphthalene that are usually present as mixtures at least in abiotic materials such as technical chloronaphthalene formulations (e.g. Halowax mixtures), and wastes containing Halowaxes and other CN formulations.