Workflow for differential analysis of whisky using an Orbitrap Exploris GC 240 mass spectrometer

Importance of the topic

Whisky profiling is critical to protect the industry from counterfeiting and quality degradation while ensuring authenticity, as it is a high-value product with complex aging processes that yield unique sensory and chemical characteristics.

Aims and study overview

This application note presents a streamlined workflow for differential analysis of Scotch whiskies and a brandy control using headspace SPME Arrow extraction, Orbitrap Exploris GC 240 high-resolution accurate mass detection, and Compound Discoverer software for untargeted profiling and statistical comparison.

Used methodology and instrumentation

Sample preparation involved diluting 100 µL of whisky to 4 % ethanol, blanks, and pooled QC. Automated headspace extraction was performed on a TriPlus RSH SMART autosampler using a DVB/C-WR/PDMS SPME Arrow fiber at 40 °C for 10 min. Chromatography used a TRACE 1610 GC with a TraceGOLD TG-624SilMS column (30 m × 0.25 mm × 1.4 µm) under a 40 °C to 270 °C ramp (10 °C/min). The Orbitrap Exploris GC 240 acquired full-scan EI (40–600 m/z) and PCI (50–600 m/z) data at 120 000 resolution. Data were processed in Chromeleon CDS 7.3.2 and Compound Discoverer 3.3, leveraging NIST 2023 and Flavour and Fragrance HRAM libraries.

Main results and discussion

PCA of replicate injections separated the five Scotch whiskies and brandy control, reflecting differences in age and production. Volcano plots identified marker compounds, including elevated long-chain ethyl esters (ethyl butanoate, hexanoate, octanoate, dodecanoate) in older whiskies, and higher 2/3-methyl-1-butanol and furfural in malt whiskies. Identification was confirmed by high library match scores (SI > 700, HRF > 90 %) and PCI molecular ion adduct patterns.

Benefits and practical applications

This integrated approach offers minimal sample preparation, rapid non-target full-scan HRAM analysis, automated deconvolution, and robust statistical tools within a single software platform, facilitating quality control, fraud detection, and product authentication in the whisky industry.

Future trends and potential applications

Advances may include expanded spectral libraries, machine learning for pattern recognition, real-time production monitoring, integration with orthogonal techniques (e.g., LC-MS, IMS), and portable HRAM instruments to further enhance authentication workflows across beverage and food sectors.

Conclusion

The SPME Arrow–Orbitrap Exploris GC 240–Compound Discoverer workflow delivers comprehensive, high-confidence differential profiling of whisky samples, enabling reliable marker compound identification and supporting industry needs for authenticity verification and quality assurance.

References

1. Warner NA, Riccardino G, Roberts D, Kutscher D. Workflow for differential analysis of whisky using an Orbitrap Exploris GC 240 mass spectrometer. Thermo Fisher Scientific Application Note 003374, 2024.
2. Thermo Fisher Scientific. Non-targeted analysis of whisky using SPME Arrow and Orbitrap Exploris GC 240 mass spectrometer, Application Note 003094, 2024.
3. Thermo Fisher Scientific. Differential analysis of soil using the Orbitrap Exploris GC 240 mass spectrometer and Compound Discoverer software, Application Note 001605, 2023.
4. Thermo Fisher Scientific. Improved identification of extractable and leachable substances with the Orbitrap Exploris GC 240 MS, Application Note 002733, 2024.
5. Thermo Fisher Scientific. Untargeted screening and identification of substances in plastic food contact materials using an Orbitrap Exploris GC 240 mass spectrometer, Application Note 001607, 2022.