Custom GC×GC configuration for the selective isolation or removal of compounds from complex samples

Abstract

We developed a novel approach to selectively isolate or remove nearly any compound from complex mixtures of volatile organic compounds. This was achieved by customizing a GC×GC system with a Deans switch, a passive splitter, and a custom-made adapter for sample recollection. The new setup was evaluated with 106 standard chemicals covering a wide range of volatility (boiling points: 56 – 343 ⁰C) and polarity (log P: 0.2 – 9.4). The method was used to remove two notorious malodorous compounds from spoiled wine samples. We found that the recovery can be maximized if a custom-made adapter is attached directly on the flame ionization detector port (average recovery rate of 76 ± 7 % for the standards). Eventually, we could selectively isolate or remove chemicals with peaks separated by a minimum distance of 50 ms for the second column throughout the whole chromatographic run. The developed system is expected to mainly be used in the field of flavor and fragrance analysis (i.e., selection of flavors and odorants of interest or removal of off-flavor or malodorous compounds). At present, we can reasonably collect about 100 ng of each single compound and are currently working on sample enrichment to improve our method to isolate sufficient amounts for further chemical analysis (e.g. high sensitivity nuclear magnetic resonance or chemical ionization tandem mass spectrometry).