Thermo Scientific Q Exactive UHMR Hybrid Quadrupole-Orbitrap mass spectrometer - PRODUCT SPECIFICATIONS

Importance of the Topic

Native mass spectrometry and top-down proteomics require instruments capable of analyzing intact proteins and large non-covalent assemblies with high resolution, mass accuracy, and sensitivity. These capabilities are essential for structural biology, detailed protein characterization, and quality control of biotherapeutics. The Q Exactive UHMR hybrid Quadrupole-Orbitrap addresses this need by extending the accessible mass range and enhancing performance in the ultra-high mass regime.

Objectives and Study Overview

This document presents the design features and performance metrics of the Q Exactive UHMR system. It aims to highlight key technology innovations, quantify improvements in mass range, resolution, and sensitivity, and demonstrate the instrument’s utility for native MS and native top-down analyses of proteins and complexes.

Methodology and Instrumentation Used

The instrument integrates multiple advanced components to achieve ultra-high mass performance:

• In-source trapping in the injection flatapole region for improved desolvation, ion cloud focusing, and controlled fragmentation.
• Low frequency RF ion guides and segmented HyperQuad mass filter (Advanced Quadrupole Technology) to enhance ion transmission and precursor isolation up to m/z 25,000.
• Active Beam Guide (AABG) and RF lens to maximize sensitivity and robustness by focusing ions into tight beams.
• Thermo Scientific Ion Max API source with H-ESI II probe, dual desolvation zones, and sweep gas for noise reduction and stable spray at flow rates from <1 μL/min to 1 mL/min.
• Nitrogen-filled combo C-Trap and HCD collision cell for efficient fragment ion extraction and trapping, enabling high-quality MS/MS and pseudo-MS3 workflows.
• Orbitrap mass analyzer with a 5 kV central electrode, low-noise preamplifier, and adjustable voltage ramp for enhanced transmission of high mass ions.
• A differentially pumped vacuum system with tunable pressure control, multiple turbomolecular pumps, and a final vacuum of <1×10^-9 mbar to maintain optimal ion packet integrity.
• Software suite including Xcalibur and Exactive Series Method Editor for instrument control, real-time data acquisition, calibration, and high-resolution data processing.

Key Results and Discussion

Performance testing under defined conditions (e.g., CsI clusters) yielded:

• Resolution of up to 200,000 (FWHM) at m/z 400.
• Mass range extending from m/z 350 to 80,000.
• Quadrupole isolation capability up to m/z 25,000 for SIM, MS/MS, and pseudo-MS3 experiments.
• Scan rates of 12 Hz at a resolution setting of 12,500 (m/z 400).
• Mass accuracy below 1 ppm RMS (internal calibration) and below 3 ppm RMS (external calibration).
• Dynamic range greater than 5,000:1.

These results demonstrate significant gains in sensitivity and resolution for analyzing megadalton assemblies, with efficient ion transmission and accurate mass measurement enabling detailed structural insights.

Benefits and Practical Applications of the Method

The Q Exactive UHMR provides:

• Unrivaled sensitivity and resolution for native MS and native top-down workflows.
• Ability to characterize large protein complexes and non-covalent assemblies, facilitating structural biology research.
• Robust performance for biotherapeutic analysis, including quality assessment of highly engineered proteins.
• Flexibility to perform MS/MS and pseudo-MS3 experiments with high mass precursors for deeper sequence coverage.

Future Trends and Opportunities

Ongoing developments may include:

• Further extension of the mass range beyond m/z 80,000 for even larger assemblies.
• Integration with ultra-high-performance liquid chromatography and nanospray techniques for seamless workflows.
• Improved throughput through faster scan speeds and real-time data processing using AI-driven algorithms.
• Enhanced automation and data-dependent acquisition strategies for complex mixture analysis.
• Application to emerging fields such as native glycoproteomics and hybrid structural approaches combining MS with cryo-EM or SAXS.

Conclusion

The Q Exactive UHMR hybrid Quadrupole-Orbitrap mass spectrometer represents a significant advancement in the analysis of high-mass biomolecules. By combining innovative ion optics, advanced quadrupole isolation, and high-resolution Orbitrap detection, it offers researchers unparalleled capabilities for native MS, top-down proteomics, and structural characterization of large protein assemblies.

References

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