Profiling the elemental composition of whisky using inductively coupled plasma mass spectrometry (ICP-MS)

Significance of the Topic

Elemental profiling by ICP-MS offers a highly sensitive method to verify whisky origin and detect adulteration through characteristic trace and ultra-trace element patterns.

Objectives and Study Overview

This application note demonstrates a comprehensive elemental analysis of ten whisky and brandy samples to assess differences linked to geological origin and production processes.

Methodology and Instrumentation

• Instrument: Thermo Scientific iCAP MSX ICP-MS with iSC-65 autosampler.
• Sample preparation: Fourfold dilution of samples in 1% HNO₃ and 10% ethanol to reduce alcohol content and match the calibration matrix.
• Internal standards: Rh and Ir at 5 µg/L for drift correction.
• Calibration: Matrix-matched standards covering 0.1–500 µg/L for major elements and 0.01–1 µg/L for lanthanides.
• Measurement mode: Sensitivity mode with Intellilens, helium KED for polyatomic interference removal, and survey scans for unexpected analyte screening.

Main Results and Discussion

The method achieved excellent linearity (R²>0.998) and low method detection limits (up to 2.8 µg/L after dilution). QC recoveries ranged from 80% to 120%. Major elements (Na, K, Mg, Ca) were found at µg/L to mg/L levels, limiting their discriminatory power. Transition metals exhibited significant variability (e.g., Cu from 10.7 to 1641 µg/L; anomalously high V and Cr in specific samples), reflecting processing or equipment effects. Lanthanide distributions varied strongly, indicating soil influence on raw materials. Arsenic levels separated samples into high (≈12 µg/L) and low (≈0.5 µg/L) groups, suggesting regional or storage-material factors.

Benefits and Practical Applications

• Authentication of whisky origin and detection of mislabeling.
• Quality control and monitoring of production consistency.
• Fingerprinting of processing steps via trace metal signatures.
• Complementary use alongside volatile compound analysis for comprehensive screening.

Future Trends and Potential Applications

Applying multivariate and chemometric analyses can enhance sample discrimination. Expanding element panels, incorporating isotopic ratio measurements, and extending the approach to other spirits will broaden applicability. Advances in high-throughput and portable ICP-MS systems may enable on-site screening at production facilities.

Conclusion

This study confirms that ICP-MS with minimal sample preparation reliably profiles whisky elemental composition, providing a robust tool for origin verification and quality assurance in the spirits industry.

References

• Application Note 3094: Whisky profiling using non-target analysis with headspace Arrow solid phase microextraction with high resolution accurate mass spectrometry; Thermo Fisher Scientific.