Improved Metabolite Structural Elucidation as a Result of Enhanced Resolution and Mass Accuracy Provided by the Select Series MRT

Importance of the Topic

Discovery metabolomic studies rely on precise and accurate mass spectrometric data to identify novel biomarkers in health and disease research. Enhanced mass resolution and accuracy are essential for confident structural elucidation and reliable biological interpretation.

Study Objectives and Overview

This application note evaluates the performance improvements afforded by the SELECT SERIES™ MRT mass spectrometer when analyzing human plasma samples. Key goals include assessing mass resolution, mass accuracy, scan speed, and applicability to biomarker discovery workflows.

Methodology and Instrumentation

• Sample Preparation: Lipid and polar metabolite extraction from plasma samples of mild and severe COVID-19 patients using a methyl-tert-butyl ether (MTBE) protocol. A pooled QC sample was injected periodically to monitor data quality.
• Liquid Chromatography: HILIC separation on an ACQUITY I-Class system with optimized gradient and column parameters.
• Mass Spectrometry: SELECT SERIES MRT operated in continuum MSe mode in both positive and negative ESI. Extended flight path (50 m) with gridless mirror reflectrons; collision energy ramp 20–40 eV; scan time 0.1 min; acquisition rate up to 20 spectra/sec; mass range 50–2400 m/z; ESI capillary 2.0 kV; source 120 °C; desolvation 500 °C; gas flows 50 L/hr cone, 800 L/hr desolvation.

Main Results and Discussion

• Mass Accuracy: Sub-ppm performance (21–134 ppb) across selected endogenous metabolites, enhancing elemental composition assignments.
• Mass Resolution: Up to 224,770 FWHM enabled resolution of co-eluting lipids (e.g., PC 34:2 vs. PC 34:1) and their isotopic peaks, unachievable with conventional ToF systems.
• Scan Speed: Acquisition of >25 data points across narrow UPLC peaks (<10 s) supports accurate peak integration for quantitative as well as qualitative analyses.

Benefits and Practical Applications

The SELECT SERIES MRT offers stable, high mass accuracy and resolution at rapid acquisition rates, facilitating reliable biomarker discovery, structural elucidation, and potential quantitation in clinical and industrial metabolomic workflows.

Future Trends and Applications

Emerging directions include integrating cyclic ToF architectures into routine metabolomics, coupling with ion mobility separation, expanding lipidomics coverage, and leveraging data-independent acquisition strategies for comprehensive molecular profiling and personalized medicine applications.

Conclusion

The SELECT SERIES MRT instrument demonstrates exceptional ppb-level mass accuracy, ultra-high resolution, and fast scan rates. These combined attributes enable confident metabolite identification, structural elucidation, and quantitative capabilities in high-throughput LC-MS metabolomics.

Reference

1. Matyash V., Liebisch G., Kurzchalia T.V., Schevchenko A., Schwudke D. Lipid Extraction by Methyl-Tert-Butyl Ether for High-Throughput Lipidomics. Journal of Lipid Research. 49(5):1137–1146.
2. Fahy E., Subramaniam S., Murphy R., Nishijima M., Raetz C., Shimizu T., Spener F., Van Meer G., Wakelam M., Dennis E. Update of the Lipid Maps® Comprehensive Classification System for Lipids. Journal of Lipid Research. 50:S9–S14 (2009).