MSUM 2017: Applying New GC-Orbitrap™ MS Functionalities to Extractables and Leachables and Metabolomics Analyses

Significance of the Topic

The identification of extractables, leachables and small-molecule metabolites is critical in pharmaceutical, environmental and food analysis. High-resolution accurate-mass GC-MS enables comprehensive screening, confident compound annotation and regulatory compliance for safety and quality control.

Objectives and Study Overview

This study presents new functionalities of the Thermo Scientific GC-Orbitrap™ mass spectrometry platform applied to unknown screening in extractables and leachables (E&L) workflows and metabolomics. Key enhancements include automated library searching with retention indexing, specialized high-resolution libraries and variable electron energy tuning to improve molecular ion detection.

Methodology

The work combines full-scan GC-Orbitrap MS acquisition with data deconvolution, formula confirmation and retention index scoring. Unknown peaks are detected by deconvolving total ion chromatograms, generating clean spectra, matching against HRAM libraries and verifying elemental compositions through high-resolution fragment (HRF) scoring.

Instrumentation Used

• Thermo Scientific™ TRACE™ 1310 GC System with modular injector and rapid heat cycling
• ExtractaBrite™ ion source with robust RF lens and vacuum-break removal
• Curved Linear Trap (C-trap), bent Flatapole, and Orbitrap mass analyzer
• Q Exactive™ GC and Exactive™ GC for MS and MS/MS workflows
• Thermo Scientific™ TraceFinder™ and Compound Discoverer™ software for automated deconvolution and CI detection

Key Results and Discussion

• Resolving power up to 120,000 and mass accuracy <1 ppm enable grouping of isobaric species and formula confirmation of library hits.
• Automated library search incorporating Kovats retention indexing improves discrimination between structurally similar compounds.
• New GC-Orbitrap metabolomics library of over 800 derivatized metabolites and contaminant library of 700+ compounds accelerate unknown identification.
• Variable electron energy (VeV) tuning enhances molecular ion signal in EI mode—S/N ratios increased by orders of magnitude at lower energies.
• Positive chemical ionization (PCI) provides complementary adducts for molecular weight confirmation of labile analytes.
• Case studies demonstrate correction of misassigned structures in E&L studies and elucidation of unknown oligomers with high-resolution fragmentation.

Benefits and Practical Applications

• Full-scan, high-resolution analysis supports quantitation equivalent to triple-quad methods without targeted MS/MS.
• Comprehensive screening of E&L compounds in packaging and device extracts improves safety assessments.
• Enhanced metabolite coverage and reliable annotation facilitates biomarker discovery in metabolomics.
• Streamlined workflows and automated identification reduce time-to-result for QA/QC and research laboratories.

Future Trends and Applications

With continued expansion of high-resolution spectral libraries and incorporation of AI-driven data processing, GC-Orbitrap MS will further advance untargeted analysis. Emerging directions include automated retention index calibration, real-time unknown identification, hybrid ionization strategies and integration with multi-omics platforms for deeper molecular insights.

Conclusion

The new GC-Orbitrap functionalities—retention indexing, high-resolution libraries and variable electron energy tuning—significantly improve confidence in unknown compound identification. This enables robust extractables & leachables screening and comprehensive metabolomic profiling, meeting stringent regulatory and research demands with high accuracy and efficiency.