Elemental profiling of Malbec Wines for geographical origin using an Agilent 4200 MP-AES

Significance of Topic

Establishing the provenance of premium wines is critical for quality assurance, consumer confidence, and protection against fraud. Elemental fingerprinting leverages soil-derived mineral profiles to verify geographical origin, offering a scientifically robust approach to wine authentication.

Objectives and Study Overview

This study evaluates the feasibility of using Microwave Plasma–Atomic Emission Spectroscopy (MP-AES) combined with multivariate chemometrics to distinguish Malbec wines from Argentina and the United States. A total of 41 wines from controlled winemaking facilities were analyzed to determine whether six key elements (Sr, Rb, Ca, K, Na, Mg) provide sufficient discriminatory power.

Methodology and Instrumentation

The wines were diluted 1:50 in 5% HNO₃ and measured in triplicate. Calibration employed six-point matrix-matched standards (0–500 mg/L) in 5% HNO₃/0.2% ethanol. An Agilent 4200 MP-AES, fitted with a MicroMist nebulizer, baffled cyclonic chamber, and External Gas Control Module (EGCM), was used. A cesium ionization buffer (2 000 mg/L Cs in 1% HNO₃) was added online. Elemental emission wavelengths were optimized for interference-free detection. Data analysis in RStudio and Agilent’s Mass Profiler Professional included MANOVA, ANOVA, PCA, and PLS-DA.

Main Results and Discussion

Detection limits ranged from 0.0004 mg/L (Rb) to 0.0020 mg/L (K). All six elements showed significant variance (p ≤ 0.05) between regions. PCA revealed clear clustering by country, driven primarily by Na and Sr differences. PLS-DA achieved 95.1% overall classification accuracy (96.2% for Argentina, 93.3% for the US), with only two samples misclassified, highlighting the robustness of the MP-AES approach.

Benefits and Practical Applications

MP-AES offers a lower-cost, user-friendly alternative to ICP-MS for elemental profiling. When paired with chemometric modeling, it reliably distinguishes geographic origin of wines. The method can be implemented in quality control laboratories to authenticate high-value products and support regulatory compliance.

Future Trends and Opportunities

• Expand sample sets across vintages and terroirs to strengthen model generality.
• Integrate isotopic ratio analysis and trace organic markers for enhanced discrimination.
• Develop portable MP-AES platforms for in-field authentication.
• Apply advanced machine-learning algorithms to refine classification accuracy.

Conclusion

This work demonstrates that MP-AES, combined with multivariate analysis, delivers a cost-effective, accurate tool for wine origin verification. Six elements—Sr, Rb, Ca, K, Na, Mg—are sufficient to classify Malbec wines by country with high precision.

Instrument Used

Agilent 4200 Microwave Plasma–Atomic Emission Spectrometer with MicroMist nebulizer, baffled cyclonic spray chamber, External Gas Control Module, and cesium ionization buffer.

Reference

Nelson J, Hopfer H, Gilleland G, Cuthbertson D, Boulton R, Ebeler SE. Elemental profiling of Malbec wines made under controlled conditions by microwave plasma atomic emission spectroscopy. Am J Enol Vitic. Published ahead of print April 2015.