Differentiation of Fresh and Oxidized Wine Samples with HS-SPME, GC-TOFMS, and GC×GC-TOFMS

Significance of the topic

This study addresses the critical need to monitor wine oxidation, a major factor affecting aroma, flavor, and product quality in the beverage industry. Accurate volatile profiling enables quality control, storage optimization, and process improvement.

Objectives and study overview

The primary goal was to differentiate fresh and intentionally oxidized wine samples using headspace solid-phase micro-extraction (HS-SPME) coupled with gas chromatography–time-of-flight mass spectrometry (GC-TOFMS) and comprehensive two-dimensional GC×GC-TOFMS. The study aimed to identify oxidation markers that are otherwise hidden in conventional analyses.

Methodology and Used Instrumentation

Samples were prepared by adding salt to 10 mL wine, incubating at 65 °C, and extracting volatiles with a 2 cm DVB/CAR/PDMS fiber. Two analytical configurations were applied:

• GC-TOFMS: Agilent 7890 GC with MPS2 autosampler, Rxi-5ms column, LECO Pegasus HT, 33–500 m/z at 15 spectra/s.
• GC×GC-TOFMS: Same primary GC, Rxi-17 Sil MS secondary column, LECO Pegasus 4D, 200 spectra/s, 2 s modulation, dual-oven temperature offset.

Results and Discussion

Initial total ion chromatograms for fresh and oxidized samples appeared similar. Advanced data processing revealed key differences:

• A sulfur compound was ninefold higher in fresh wine, despite being masked in the TIC.
• Sulfur dioxide, used as an antioxidant, measured three times higher in fresh samples.
• Benzaldehyde levels doubled in the oxidized wine, indicating oxidation pathways.
• GC×GC improved signal-to-noise via thermal focusing and resolved coelutions, identifying 2-methylthio-ethanol and other volatiles undetected in one-dimensional analysis.

Benefits and Practical Applications

The combination of HS-SPME with GC-TOFMS and GC×GC-TOFMS provides a non-targeted, high-resolution approach for volatile profiling in complex matrices. This workflow supports enology quality assurance, shelf-life evaluation, and investigative research in food and beverage industries.

Future Trends and Potential Applications

Emerging developments may include faster modulation devices, enhanced deconvolution algorithms, and integration with machine-learning tools for automated pattern recognition. These advances could enable real-time oxidation monitoring and broader applications in environmental and pharmaceutical analyses.

Conclusion

Advanced chromatography and mass spectrometry, coupled with sophisticated data deconvolution, successfully differentiated fresh and oxidized wine. Two-dimensional GC×GC-TOFMS notably increased detection of subtle oxidation markers, offering deeper insights into aroma chemistry.

References

No specific literature references were provided in the source document.