High Resolution Accurate Mass GC-MS based on Orbitrap Technology - A new chapter in GC-MS

Significance of High-Resolution Accurate Mass GC-MS Based on Orbitrap Technology

High-resolution accurate mass (HRAM) GC–MS transforms routine and advanced analyses by combining gas chromatography separation with Orbitrap mass spectrometry precision.
It offers exceptional selectivity, sub-ppm mass accuracy and extended linear dynamic range, addressing complex matrices in fields such as food safety, environmental monitoring, metabolomics and pharmaceutical quality control.

Study Objectives and Overview

This webinar introduced the Thermo Scientific Orbitrap GC–MS family, highlighting:

• The Q Exactive GC system with 120 000 resolving power at m/z 200 and MS/MS capability
• The Exactive GC system offering 60 000 resolving power for routine analyses
• Main workflows for targeted quantitation, targeted screening and non-targeted screening
• Key application areas and representative case studies

Methodology and Instrumentation

The analytical platform consists of a modular TRACE 1310 GC with fast cycle times and ExtractaBrite ion source technology featuring a patented RF lens and vacuum-free column changeover.
Mass analysis is performed in an Orbitrap mass analyzer delivering:

• Resolving power up to 120 000 (FWHM at m/z 200)
• Mass accuracy better than 1 ppm
• Dynamic range exceeding six orders of magnitude
• Fast acquisition rates suitable for narrow GC peaks (e.g., ~17 scans per 2.4 s peak at 60 000 RP)

Main Results and Discussion

Key performance highlights include:

• Sub-ppt sensitivity and triple-quad–grade quantitation in full-scan mode
• Scan-to-scan mass accuracy < 1 ppm across broad concentration ranges without frequent calibration
• Excellent spectral fidelity enabling confident identification via isotopic patterns and fragment ions
• High-resolution deconvolution supporting non-targeted workflows with NIST library matching and high-resolution filtering

Applications demonstrated:

• Pesticide quantitation in baby food: linearity (R2 > 0.99), IDLs < 2 ng/g for 91 % of 132 compounds, area RSD ~ 6 %
• Screening of iodinated disinfection by-products in tap water via accurate mass filter (m/z 126.90392)
• Non-targeted metabolomics for post-mortem biomarkers in rat muscle combining multivariate analysis and structural interpretation
• Drugs of abuse detection in urine by full-scan screening with library matching
• Leachable impurity identification from polymeric O-rings with sub-ppm accuracy and interference removal

Benefits and Practical Applications

Orbitrap GC–MS systems deliver:

• Unmatched selectivity for complex matrices
• Comprehensive profiling in both targeted and untargeted modes
• Reduced method development time through automated tuning, calibration (< 1 min) and vacuum-free source or column changes
• Single-platform capability for quantitative, qualitative and structural elucidation studies

Future Trends and Potential Uses

Advancements may include:

• Expanded spectral libraries and machine-learning integration for accelerated compound identification
• Enhanced coupling with ion mobility or multidimensional chromatography
• Real-time screening applications in environmental and clinical monitoring
• Deeper integration with informatics platforms for automated data processing and regulatory compliance

Conclusion

Thermo Scientific Q Exactive and Exactive GC systems establish a new standard in GC–MS by merging high-resolution Orbitrap analyzers with robust GC design.
They provide routine-ready HRAM performance that rivals triple-quadrupole sensitivity, with comprehensive workflows for targeted quantitation and discovery-based screening across diverse analytical fields.

Reference

• Webinar: "High Resolution Accurate Mass GC-MS based on Orbitrap Technology", Thermo Fisher Scientific, 25 November 2016
• Mol H. and Tienstra M., RIKILT – data supporting scan-to-scan mass accuracy performance