A Taste of the Other Side

Importance of the Topic

The accurate detection and quantification of residues and contaminants in food, environmental, and pharmaceutical samples is critical for ensuring safety, regulatory compliance, and consumer confidence. High-resolution accurate-mass (HRAM) gas chromatography–mass spectrometry (GC-MS) using orbitrap technology offers unprecedented selectivity and sensitivity, enabling comprehensive targeted quantification and untargeted screening in a single analytical run.

Objectives and Overview

This article presents insights from Dr Richard Fussell, an analytical chemist with extensive experience in government research and a recent role at Thermo Fisher Scientific. The discussion focuses on the rationale behind the development of the Q Exactive GC Orbitrap system and the factors influencing its adoption in food safety and environmental laboratories.

Methodology and Instrumentation

Moving beyond traditional GC single-quadrupole and triple-quadrupole systems, the Q Exactive GC integrates a high-resolution orbitrap mass analyzer with full-scan acquisition. Key features include:

• Mass resolution exceeding 60 000 (FWHM) for clear separation of isobaric interferences
• Sub-ppm mass accuracy for confident compound identification
• Simultaneous targeted quantification and broad non-target screening workflows

Main Results and Discussion

Early laboratory experiences with custom-built LC systems and single-quadrupole GC-MS highlighted the limitations in selectivity and sensitivity for complex matrices. The advent of GC-triple quadrupole improved quantification for pesticide residues, but full-scan coverage remained constrained. Preliminary evaluations of the Q Exactive GC demonstrated near-unbelievable performance, with robust quantification and comprehensive spectral libraries, paving the way for routine HRAM GC-MS applications.

Benefits and Practical Applications

The orbitrap-based GC-MS approach delivers multiple advantages:

• Enhanced signal-to-noise for trace-level contaminants
• Unified workflows reducing sample preparation and analysis time
• Capability to monitor pesticides, mycotoxins, environmental pollutants, and food authenticity markers concurrently
• Improved confidence in identification through exact mass measurement and isotopic pattern analysis

Future Trends and Applications

Emerging directions include:

• Integration of multi-class analyte screening (e.g., pharmaceuticals, endocrine disruptors) within a single run
• Full-scan workflows for real-time quality control of raw materials and food authenticity verification
• Widening adoption as instrument costs decrease and software advances automate data processing
• Development of shared spectral libraries and informatics platforms to support open-access screening

Conclusion

The transition from conventional GC-MS to orbitrap-based high-resolution systems marks a transformative step in analytical chemistry. By combining sensitivity, selectivity, and comprehensive acquisition, the Q Exactive GC expands the capabilities of laboratories in food safety, environmental monitoring, and beyond, fostering new collaborative opportunities between researchers and instrument developers.