Multiplexed dual second-dimension column comprehensive two-dimensional gas chromatography (GC × 2GC) using thermal modulation and contra-directional second-dimension columns

• A comprehensive two-dimensional GC approach with contra-directional dual second-dimension columns is introduced.
• Dual second-dimension columns are multiplexed using a novel thermal modulation regime.
• The approach uses one injector, three columns and one detector.
• Three sets of retention data are collected providing abundant qualitative information.

A multiplexed dual-secondary column comprehensive two-dimensional gas chromatography approach (GC × 2GC) designed for complex sample analysis is introduced. The approach splits the first-dimension column effluent into two second-dimension columns with different stationary phases, and recombines the two streams into one detector post-separation. The approach produces two single two-dimensional chromatograms for each injection. Careful manipulation of thermal modulator timing parameters combined with a novel contra-directional modulation regime facilitates this approach. A selection of 34 laboratory reference compounds containing n-alkanes, alcohols, aromatic hydrocarbons, ketones, esters and halogenated hydrocarbons were analysed to demonstrate the approach. The dual two-dimensional chromatogram from this single detector system provides complementary information due to the unique selectivity of the three separation columns. The results of this proof-of-principle investigation provide significant impetus for further development of GC × 2GC–MS methodology.

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