GasBench II System: Tracking wine adulteration using oxygen isotope fingerprints

Importance of the Topic

Wine adulteration through the addition of non‐grape substances such as water, fruit juices or sweeteners undermines product authenticity, consumer trust and regulatory compliance. Reliable analytical approaches are essential for distinguishing genuine wines from fraudulent counterparts and ensuring accurate labeling in accordance with international and EU legislation.

Study Objectives and Overview

This application brief demonstrates the use of oxygen isotope fingerprinting to detect water adulteration in commercial wines. By measuring δ18O values of CO2 equilibrated with wine samples, the study aims to establish a robust method for identifying watering practices and verifying origin claims against an official EU wine isotopic database.

Methodology

• Wine samples (500 µL, undistilled) are placed in sealed vials and equilibrated with 100 µL CO2 gas for 24 h at 24 °C following the OIV‐MS‐AS2‐12 protocol.
• Automated multiple loop injections draw ten replicate gas sub‐samples to improve precision in a single analytical run.
• Micro gas chromatographic separation isolates CO2, which is then analyzed for oxygen isotope ratios by isotope ratio mass spectrometry (IRMS).

Instrumentation Used

• Thermo Scientific GasBench II System for automated gas equilibration and sampling.
• Thermo Scientific DELTA V IRMS for high‐precision δ18O measurements.
• Micro GC column integrated into the GasBench II for CO2 purification prior to IRMS analysis.

Main Results and Discussion

Sequential addition of water to a genuine red wine sample produced a clear linear decrease in δ18O values, as depicted in Figure 1. This trend confirms that even minor dilution alters the isotopic signature originally imparted by vine‐derived water. By comparing measured δ18O values to those in the EU‐wineDB, laboratories can conclusively detect and quantify water adulteration while preserving information on geographical origin patterns shaped by rainfall, altitude and coastal proximity.

Benefits and Practical Applications

• Conformance with the official OIV‐MS‐AS2‐12 method and EC No 606/2009 labeling regulations.
• High sample throughput and cost‐effective operation through full automation.
• Robust, reproducible isotopic fingerprinting for detecting watered‐down or mislabelled wines.
• Enhanced protection of producer reputation and consumer confidence.

Future Trends and Potential Applications

• Expansion of global isotopic databases covering diverse wine regions.
• Integration of multi‐isotope (H, C, N) profiling for comprehensive authentication.
• Coupling IRMS data with advanced chemometric and AI‐driven analysis.
• Development of portable or field‐deployable isotope analyzers for on‐site screening.

Conclusion

Oxygen isotope fingerprinting utilizing the GasBench II System and DELTA V IRMS offers a powerful, fully automated solution for detecting water adulteration in wine. The method delivers high‐precision δ18O data, enabling laboratories to verify authenticity, comply with regulatory standards and safeguard product integrity.

References

1. Carter J.F., Yates H.S.A., Tinggi U. Journal of Agricultural and Food Chemistry 63 (2015) 5771–5779.
2. Rodrigues C., Maia R., Miranda M., Ribeirinho M., Nogueira J.M.F., Aguas C.M. Journal of Food Composition and Analysis 22 (2009) 463–471.