Selectable one-dimensional or two-dimensional gas chromatography–mass spectrometry with simultaneous olfactometry or element-specific detection

A novel selectable one-dimensional (1D) or two-dimensional (2D) gas chromatography–mass spectrometry (selectable 1D/2D GC–MS) system with selective detection was developed by using capillary flow technology and low thermal mass GC (LTM-GC). The main advantages of this system are the simple and fast selection of 1D GC–MS or 2D GC–MS operation without any instrumental set-up change (e.g. 2D GC–MS can be run just after 1D GC–MS run), and simultaneous mass spectrometric and olfactometry or element-specific detection for both 1D and 2D separation to assure selection of a heart-cut region and correct identification of compounds of interest. The feasibility and benefit of the proposed system with selective detection, e.g. olfactometry, nitrogen phosphorus detection (NPD), and pulsed flame photometric detection (PFPD), was demonstrated with an identification of trace amounts of aroma components in beverages (beer and coffee). Using stir bar sorptive extraction (SBSE) and selectable 1D/2D GC–Olfactometry/MS on a beer sample, β-damascenone could be determined at 1.9 ng mL−1 (RSD 3.1%, n = 6) as a potent aroma compound. In a coffee sample, two odor active compounds were clearly resolved from a 4.2 s heart-cut and were assigned probable identifications as 4,5-dimethyl thiazole and dimethyl trisulfide based on a NIST library search, dual linear retention indices (dual LRI) and elemental information obtained by SBSE in combination with selectable 1D/2D GC–NPD/PFPD/MS.