Applying high resolution GC-Orbitrap mass spectrometry for the quantitative analysis of environmental contaminants in food

Significance of the topic

Environmental laboratories require highly sensitive, selective, and efficient analytical methods to meet growing demands for quantifying trace levels of pesticides, PCBs, PAHs, and BFRs in diverse food matrices. High-resolution GC-Orbitrap mass spectrometry addresses challenges related to throughput, method flexibility, and retrospective data analysis.

Objectives and study overview

This study assesses the performance of a benchtop Orbitrap Exploris GC-MS for quantifying environmental contaminants in food and compares it to a conventional triple quadrupole GC-MS/MS. Key objectives include evaluating sensitivity, linearity, limits of detection and quantitation, and accuracy in proficiency tests using real and spiked samples.

Methodology and instrumentation used

Sample preparation involved accelerated solvent extraction or Soxhlet extraction with 13C-labeled or deuterated internal standards, followed by cleanup using Florisil™, silica SPE, or sulfuric acid silica. Chromatographic separation was achieved on a TRACE™ 1610 GC with a TraceGOLD™ TG-5SilMS column. An Orbitrap Exploris GC operated in full-scan mode at 60,000 resolution (m/z 50–600) provided high-accuracy mass measurements, while a TSQ™ 9610 triple quadrupole GC-MS/MS served as a reference. Data acquisition and processing used Chromeleon™ CDS.

Main results and discussion

• Linearity: Calibration was linear across 0.1–2000 pg/µL with R2 values ≥0.995 for most analytes and ≥0.999 for PCBs and OCPs.
• Sensitivity: OCPs and PCBs achieved LOQs below 0.1 pg/µL; BFRs had LOQs <1 pg/µL; PAHs showed precision better than 10% at 1 pg/µL.
• Proficiency testing: Both HRAM and triple quadrupole systems delivered z-scores within ±2, confirming accuracy in fish and olive oil samples.
• Comparison: The Orbitrap Exploris GC-MS matched the triple quadrupole’s quantitative performance while enabling full-scan acquisition and retrospective screening.

Benefits and practical applications

The method simplifies setup with untargeted full-scan acquisition, allowing the simultaneous screening of multiple compound classes and post-acquisition data mining. High mass accuracy improves selectivity in complex matrices, streamlining QA/QC and environmental monitoring workflows.

Future trends and potential applications

Anticipated developments include wider adoption of HRAM GC-MS for multi-class contaminant screening, integration with AI-driven data analysis, enhanced automation, and expanded use in regulatory compliance, food safety, and environmental surveillance.

Conclusion

The Orbitrap Exploris GC-MS offers robust sensitivity, excellent linearity, and quantitation performance comparable to triple quadrupole systems, combined with the versatility of full-scan acquisition and retrospective analysis, making it a valuable tool for trace contaminant analysis in food.

Used Instrumentation

• Thermo Scientific TriPlus RSH autosampler
• Thermo Scientific TRACE 1610 GC with TraceGOLD TG-5SilMS 30 m × 0.25 mm × 0.25 µm column
• Orbitrap Exploris GC-MS (60,000 resolution, m/z 50–600 full scan)
• TSQ 9610 triple quadrupole GC-MS/MS
• Chromeleon™ Chromatography Data System (CDS)
• Accelerated solvent extraction (ASE) and Soxhlet extraction equipment