Supporting exposomics research with the Orbitrap Exploris GC 240 mass spectrometer

Significance of the Topic

Exposomics examines the totality of environmental exposures over a lifetime and their biological responses. By moving beyond targeted compound lists, exposomics seeks to identify non-genetic factors driving disease. Comprehensive detection of chemicals in complex matrices is critical for understanding mechanisms of toxicity and guiding prevention strategies.

Objectives and Study Overview

This case study describes how the Orbitrap Exploris GC 240 mass spectrometer and associated software workflows enable high-resolution, non-targeted exposome analysis. Researchers at Emory University aim to scale detection from hundreds to tens of thousands of exposures per sample, supporting discovery of unknown contaminants and their links to health outcomes.

Methodology and Instrumentation

The workflow uses high-resolution accurate mass (HRAM) full-scan GC-MS on the Orbitrap Exploris GC 240 system, achieving resolving power up to 240,000 (m/z 200) and mass accuracy below 1 ppm. Sample types include soil, air, water, food, and biological fluids. Data processing employs Thermo Scientific Compound Discoverer software for peak detection, statistical analysis, and unknown identification. Compound annotation integrates the Orbitrap GC-MS HRAM Contaminants Library (>1,200 EI spectra) together with NIST nominal mass libraries for spectral matching and retention index confirmation.

Main Results and Discussion

Using the high-resolution GC-MS platform, the team expanded screening capacity from hundreds to approximately 100,000 chemical signals per sample. HRAM data allowed sensitive detection of low-level exposures and reliable differentiation in complex matrices. Retrospective data mining further enabled identification of compounds not targeted during acquisition, enhancing discovery potential.

Benefits and Practical Applications

• Simultaneous targeted quantitation and non-targeted screening in a single run.
• High sensitivity and selectivity for diverse chemical classes.
• Robust library matching and structural elucidation of unknowns.
• Retrospective analysis capability for emerging contaminants.

Future Trends and Potential Applications

Advances may include integration of ion mobility separation for additional selectivity, expansion of spectral libraries for novel compounds, and application of machine learning for automated annotation. High-throughput exposome profiling could inform precision medicine, epidemiological studies, and regulatory monitoring.

Conclusion

The Orbitrap Exploris GC 240 combined with Compound Discoverer software delivers a powerful platform for exposomics, enabling extensive non-targeted screening, accurate identification, and comprehensive exposure assessment. This approach advances our ability to link complex environmental mixtures to health outcomes.

Reference

1. Fuentes, M. et al. Operationalizing the Exposome Using Passive Silicone Samplers. Current Pollution Reports, 2002, 8, 1–29.
2. Thermo Fisher Scientific. Mass Resolving Power of 240,000: For Confident Compound Identification. Technical Note 10730, 2021.