MS Imaging – The SELECT SERIES™ MALDI and MRT

Importance of the Topic

Mass spectrometry imaging (MSI) without prior separation enables spatially resolved molecular profiling in biological tissues. However, spectral complexity and isobaric interferences can limit identification confidence. Ultra-high resolving power and mass accuracy are critical to distinguish overlapping signals and ensure reliable biomolecular localization.

Objectives and Study Overview

This study evaluates the performance of a novel MALDI source integrated with a quadrupole multi-reflecting time-of-flight (Q-MRT) analyzer. The goal is to achieve >200,000 FWHM resolving power and sub-ppb mass accuracy at high scan rates. Murine brain sections were imaged at 15 μm and 50 μm resolutions to demonstrate lipid mapping, isobaric separation, and acquisition speed.

Methodology and Instrumentation Used

• Sample Preparation: 2,5-dihydroxybenzoic acid matrix applied via automated HTX M5 sprayer
• Laser System: 2.5 kHz Nd:YAG solid-state laser delivering 15–50 μm pixel sizes
• Ion Transfer: StepWave™ XS hexapole and orthogonal ion guides with optional MS/MS quadrupole and XS collision cell for CID
• Mass Analyzer: Hybrid Q-MRT with 47 m folded flight path and gridless ion mirrors (46 reflections)
• Data Acquisition: MassLynx™ v4.2 and HDI v1.6 software, internal lockmass correction

Main Results and Discussion

High-quality lipid images were generated at 15 μm resolution in ~12 hours and at 50 μm in ~80 minutes, maintaining >200,000 resolving power and <350 ppb RMS mass error. A distinct lipid envelope between m/z 700–900 was resolved, and four isobaric signals within an 86 mDa window were separated. Fine isotopic structure (<9 mDa) of PC(36:1)+K demonstrated the analyzer’s exceptional specificity and potential to aid spectrum assignment.

Benefits and Practical Applications

• Improved molecular specificity and reduced spectral overlap in complex MSI datasets
• Rapid, high-resolution imaging at biologically relevant spatial scales
• Enhanced confidence in identifying isobaric and isotopic variants for biomarker discovery

Future Trends and Potential Applications

Future directions include multimodal imaging combining MALDI-MRT with complementary ionization techniques, in situ metabolomics, and AI-driven data analysis. The technology may extend to clinical tissue diagnostics, pharmacokinetic studies, and high-throughput drug distribution mapping.

Conclusion

The combination of the SELECT SERIES MALDI source and Q-MRT analyzer establishes a new benchmark for MSI, delivering ultra-high resolution, mass accuracy, and acquisition speed. This platform enables detailed spatial mapping of lipids and other biomolecules with unprecedented confidence.

References

No external references were provided in the source document.