Elemental and isotopic analysis: solutions for food authenticity, quality and safety

Importance of the topic

Reliable elemental and isotopic analysis underpins food authenticity, quality and safety assessment. Regulatory agencies worldwide set stringent limits on toxic metals in baby foods and other products, while consumers demand transparent nutritional and origin information. Advanced analytical workflows help laboratories meet evolving requirements and ensure compliance.

Objectives and study overview

This work illustrates integrated solutions for comprehensive food analysis. Three complementary techniques are demonstrated:

• Triple quadrupole ICP-MS for multi-element quantification at trace levels
• FlashSmart elemental analyzer for carbon, hydrogen, nitrogen, sulfur and oxygen determination
• Isotope ratio mass spectrometry (IRMS) for origin and authenticity via bulk and compound-specific isotope fingerprints

Methodology and instrumentation

Triple quadrupole ICP-MS

• Thermo Scientific iCAP TQe TQ-ICP-MS with Q1, Q2 (O2) reaction cell and Q3
• Microwave digestion of baby food (HNO3/HCl), dilution (25× for wet, 125× for dry)
• Single-mode TQ-O2 mass shift method for all analytes
• Detection and quantification via mass shift (e.g. 75As→91AsO+, 78Se→96SeO+)

Elemental analyzer

• Thermo Scientific FlashSmart EA using dynamic flash combustion (modified Dumas)
• MAS Plus autosampler for solids, liquids and viscous samples
• Thermal conductivity detector for C, H, N, S and calculation of protein from nitrogen

Isotope ratio MS

• Thermo Scientific Qtegra-controlled EA IsoLink IRMS, GC IsoLink II IRMS, LC IsoLink IRMS and GasBench Plus IRMS
• Bulk and compound-specific isotope analysis to trace geographical origin, production methods and detect adulteration

Main results and discussion

ICP-MS performance

• Method LOQs in baby food below regulatory limits for As, Cd, Hg, Pb and other elements
• Interference removal validated with NIST CRMs (1515 apple leaves, 2383a baby food, BCR-063 milk powder)
• Stable QC recoveries over long runs and accurate mercury determination at near-LOQ levels confirmed by FNSQAP exercises

Elemental analysis

• Protein content of cereals, beans, dairy and meat determined with RSDs below 1 %
• Rapid throughput and precise N/protein quantification

Isotope analysis

• Carbon and nitrogen isotopes distinguish beef from C3/C4 diets and organic vs conventional crops
• Vanillin origin in foods traced by C and H isotope fingerprints
• Honey adulteration detected by EA- and LC-IRMS carbon isotope ratios
• Wine watering and geographic origin assessed via oxygen isotope ratios

Benefits and practical applications

These integrated workflows offer:

• High-sensitivity multi-element analysis with robust interference removal
• Single-mode operation to reduce method development time and increase throughput
• Comprehensive elemental composition (C, H, N, S, O) supporting nutritional labeling
• Isotopic fingerprinting for authenticity, provenance and anti-fraud screening
• Seamless software control and QA/QC with intelligent method assistants

Future trends and potential uses

Emerging directions include:

• Expansion of compound-specific isotope analysis in complex matrices
• Integration of transient signal techniques (LA-, sp-, GC-, LC-, IC-ICP-MS) for targeted applications
• AI-driven method development and data interpretation assistants
• Combined elemental and isotopic datasets for robust food forensics and supply chain transparency

Conclusion

The combination of triple quadrupole ICP-MS, dynamic flash elemental analysis and versatile IRMS provides a powerful toolbox for food authenticity, quality and safety. Laboratories can achieve regulatory compliance, streamline workflows and deliver reliable results across a wide range of food and beverage matrices.

References

• Williams N. Elemental and isotopic analysis: solutions for food authenticity, quality and safety. RAFA 2022.
• AOAC Official Method 998.12, Carbon isotope ratio method for honey adulteration.
• OIV-MS-AS2-12, Oxygen isotope analysis for wine authenticity.
• Codex Alimentarius CXS 234-1999, Recommended methods of analysis and sampling.
• CEN TC 460 WG6, Food Authenticity IRMS standards.
• Heaton K. et al. (2008) C and N isotope analysis for beef origin determination.