Spatial information analysis using a desktop size MALDI Digital Ion Trap Mass Spectrometer based on MS imaging information

Importance of the Topic

Mass spectrometry imaging (MSI) provides spatially resolved molecular information directly from biological tissues, enabling advances in pathology research, drug discovery, and clinical diagnostics. Developing a compact, user-friendly MSI instrument suitable for deployment in clinical and field environments can democratize access to this powerful tool and accelerate translational applications.

Objectives and Study Overview

This study demonstrates the feasibility of combining high-resolution MSI on a benchtop MALDI imaging system (iMScope QT) with targeted MS/MS and MS³ analyses on a desktop MALDImini-1 digital ion trap mass spectrometer. The goal was to show that spatial molecular distributions obtained by MSI can guide selective tandem MS experiments on a small-footprint instrument to confirm analyte identities in tissue samples.

Methodology and Instrumentation

Frozen mouse brain sections (10 μm) were coated with 9-aminoacridine matrix (1.0 μm) on ITO slides using an iMLayer device.

• Imaging (iMScope QT): Positive-ion mode, m/z 680–900, 10 μm laser spot, 50 shots per pixel, 500×260 points, 30 μm pitch; images generated by IMAGEREVEAL software.
• Targeted MSn (MALDImini-1): m/z 650–5000, scanning speed 4000 Da/s, MS/MS and MS³ analyses at user-selected tissue coordinates identified from MSI maps.

Main Results and Discussion

MSI of the whole brain highlighted differential distributions of phospholipid species. For example, m/z 826 (PC(36:1)+K) was enriched in the cerebellar medulla and corpus callosum, whereas m/z 734 (PC(32:0)+H) and m/z 772 (PC(33:0)+K) showed lower relative abundance. Based on these maps, specific pixels were targeted on the MALDImini-1 to acquire MS/MS and MS³ spectra. Characteristic neutral losses (–59 Da, –183 Da) and potassium adduct eliminations confirmed lipid assignments, demonstrating reliable on-tissue structural identification.

Benefits and Practical Applications

• Portability: MALDImini-1’s compact size allows installation near clinical or research sites.
• Targeted Analysis: Leveraging high-resolution MSI to guide MSn reduces overall measurement time by focusing on regions of interest.
• Structural Confirmation: MS/MS and MS³ enable definitive molecular identification directly in tissue.

Future Trends and Potential Uses

Integration of desktop ion trap systems with high-resolution MSI can support point-of-care molecular pathology and intraoperative tissue analysis. Advances in throughput, automated region selection, and multiplexed workflows are expected to broaden applications in pharmacokinetics, biomarker validation, and personalized medicine.

Conclusion

This work demonstrates that a desktop-sized MALDI digital ion trap mass spectrometer, when guided by prior MSI data, can perform spatially targeted MS/MS and MS³ on tissue sections. Combining high-speed imaging with compact MSn instrumentation offers a practical approach for on-site molecular analysis and structural confirmation.

Reference

No formal literature list was provided in the source material.