Chemical profiling of whiskies using Orbitrap GC-MS

Importance of the Topic

An accurate chemical profile of whisky ensures product authenticity, quality control and supports flavor characterization, crucial for producers and consumers alike.

Objectives and Study Overview

This proof of concept study evaluated a hybrid orbitrap GC-MS platform for untargeted chemical profiling of nine whisky samples from different origins. The goal was to detect compositional differences and propose compound identities for unique features observed across samples.

Methodology

Whisky samples were diluted with distilled water and extracted with ethyl acetate. Organic layers were dried over sodium sulfate, evaporated under nitrogen and reconstituted prior to GC injection. Each sample, including a pooled mixture, underwent four replicate injections in randomized order. Data were acquired in full scan mode across m/z 50–600.

Instrumentation

• Thermo Scientific TRACE 1310 gas chromatograph with splitless injector
• TraceGOLD TG-5SILMS column (30 m × 0.25 mm × 0.25 μm)
• TriPlus RSH autosampler
• Thermo Scientific Q Exactive GC hybrid quadrupole–orbitrap mass spectrometer
• Thermo Scientific TraceFinder and Sieve 2.2 software suites

Results and Discussion

High‐resolution full scan acquisition (60 000 FWHM) delivered sub-ppm mass accuracy, enabling detection of over 4 800 components. Principal component analysis separated bourbon and single malt whiskies and highlighted distinctive markers. Trans-β-ionone at 13.6 min was confidently identified by spectral matching and accurate mass filtering. Unknown features without library matches were assigned elemental formulas using exact mass and PCI data.

Benefits and Practical Applications

• Comprehensive untargeted profiling of complex spirit matrices
• High confidence in compound identification via sub-ppm mass accuracy
• Rapid, robust data processing through integrated chemometrics
• Applications in quality assurance, authenticity verification and product development

Future Trends and Applications

Scaling the sample set and building extensive spectral libraries will improve classification models. Coupling orbitrap GC-MS with machine learning could enable automated, real-time quality control. The approach may also extend to other beverages and food products for broader authenticity and safety screening.

Conclusion

The Q Exactive GC orbitrap platform demonstrates exceptional performance for detailed, untargeted chemical profiling of whisky, combining reliable chromatography, fast full scan acquisition and accurate mass measurement essential for in-depth compositional analysis.