This study demonstrates the use of headspace sorptive extraction coupled with GC×GC–TOF MS/SCD to provide comprehensive information on wine aroma and odour taints on a single, fullyautomated, cryogen-free platform. We also show the added value of Tandem Ionisation® for confident identification of aroma-active species that can be challenging to identify by conventional 70 eV electron ionisation alone.
Aroma profiles, such as those for wine, contain a wide variety of components at a range of concentrations. Detection and identification of key compounds with low odour thresholds and compounds responsible for off-odours is a challenging prospect.
Sampling the headspace of wine using high-capacity sorptive extraction can help to tackle this issue, by increasing sample loadings through use of a larger volume of PDMS stationary phase (65 µL compared to ~0.5 µL for SPME). Used in conjunction with secondary refocusing, this approach offers excellent sensitivity, as well as the ability to re-collect a portion of the sample for repeat analysis in a fully automated workflow using the Centri® platform from Markes International.
Despite these advances, the aroma profiles of wine still present challenges to analysts because of their complexity, with important compounds (such as trace-level sulfur species that cause undesirable odour taints) frequently masked by higher-loading components. Fortunately, comprehensive two-dimensional gas chromatography (GC×GC) coupled with time-of-flight mass spectrometry (TOF MS) can help to tackle this problem, with the enhanced separation capacity of GC×GC complementing the ability of TOF MS to provide confident identification of targets and non-targets.