MoniQA 2017: Chemical Profiling of Whiskies Using Orbitrap GC-MS

Importance of the Topic

Comprehensive chemical profiling of whisky is critical for ensuring product authenticity, monitoring production parameters and maintaining brand integrity. Detailed compositional analysis supports quality control, fraud detection and the characterization of regional or barrel aging effects in this high-value spirit.

Objectives and Study Overview

This proof-of-concept investigation aimed to apply an untargeted chemometric workflow using the Thermo Scientific Q Exactive GC Orbitrap GC-MS/MS system. The goals were to detect and identify volatile and semi-volatile components in whiskies of different origins and to highlight compositional differences through statistical analysis.

Methodology

Sample Preparation and Data Acquisition:

• 1 µL splitless injection of whisky into TRACE 1310 GC.
• Separation on a TraceGOLD TG-5SILMS column (30 m × 0.25 mm, 0.25 µm film).
• TriPlus RSH autosampler for reproducible introduction.
• Full-scan acquisition (50–600 m/z) at 60,000 FWHM resolution using the Q Exactive GC system with internal lock mass.

Used Instrumentation

• Thermo Scientific TRACE 1310 gas chromatograph.
• TraceGOLD TG-5SILMS capillary column.
• Thermo Scientific TriPlus RSH autosampler.
• Thermo Scientific Q Exactive GC Orbitrap mass spectrometer.
• Thermo Scientific TraceFinder and SIEVE 2.2 software for data processing and chemometric analysis.

Main Results and Discussion

Principal Component Analysis revealed distinct clustering of bourbon (sample 2295) and single malt (sample 2265) compared with other whiskies. A targeted review of 4,841 detected components pinpointed markers unique or elevated in sample 2295. For example:

• A feature at 13.6 min (m/z 177.1274) was confidently identified as trans-β-ionone via EI spectral matching and accurate mass filtering.
• A peak at 18.0 min showed no library match; combined EI/PCI spectra and sub-ppm mass accuracy enabled assignment of the elemental formula C12H16O5 and tentative identification as 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid, supported by mass fragmentation modeling.

Contributions and Practical Applications

The workflow demonstrated:

• High-resolution Orbitrap analysis for sub-ppm mass accuracy, facilitating confident compound identification even at low concentration.
• Robust chromatography and rapid data acquisition enabling comprehensive profiling of complex spirit matrices.
• Software-driven differential analysis (TraceFinder, SIEVE) to isolate characteristic features, supporting authentication, QA/QC and research into aging or production variables.

Future Trends and Potential Applications

Expanding this approach to larger whisky cohorts will refine marker panels for origin and age discrimination. Integration with targeted quantification methods could enable routine quality monitoring. The platform’s versatility makes it suitable for other beverage matrices, flavoromics studies and high-throughput screening in food safety and authentication contexts.

Conclusion

The Thermo Scientific Q Exactive GC Orbitrap GC-MS/MS combined with chemometric software provides a powerful, untargeted workflow for whisky profiling. The approach yields high confidence in component detection and identification, enabling differentiation of products by origin and production parameters.

References

• Roberts D, Hajslova J, Stupák M, Pulkrabova J, Cole J, Silcock P. Chemical Profiling of Whiskies Using Orbitrap GC-MS. Thermo Fisher Scientific; 2016.