Isolation of single molecules from complex GCxGC chromatograms

We developed a novel approach capable of isolating and recollecting nearly any molecule from complex GCxGC chromatograms. This was achieved by modifying a GCxGC-Q-TOF system with a Deans switch, a passive splitter, and careful adjustments of flows and capillary dimensions. The setup was evaluated with more than a hundred standard chemicals covering a wide range of volatility (boiling points: 56 – 343 ⁰C) and polarity (log P: -0.2 – 9.4). We found that recovery from tube to tube can become highly efficient if a custom-made adapter is attached directly on the FID port (average recovery rate of 76 ± 7%). Furthermore, we could achieve an isolation down to a minimum distance of 50 ms between baseline separated eluting peaks. In addition, the setup was designed for easy adaptation by repurposing existing instrument control software to define the isolation windows for the compounds of interest (first and second column retention time windows). We expect this novel development to allow several new applications, e.g., the isolation or selective enrichment of molecules in food and flavour analysis; the investigation of suspect chemicals (incl. unknowns) for effect directed analysis (e.g., bioassays), and the isolation of chemicals for further chemical analysis.