Targeted MS Imaging Solution with DESI XS and XEVO TQ Absolute

Importance of the Topic

Targeted mass spectrometry imaging provides spatially resolved molecular data with enhanced sensitivity and selectivity, crucial for visualizing low-abundance biomarkers, drug distribution, and metabolites directly from surfaces. It streamlines workflows in pharmaceutical research, pathology, and environmental analysis while reducing resource consumption and increasing confidence in molecular detection.

Objectives and Study Overview

This document presents a targeted MS imaging solution combining the DESI XS ion source with the Xevo TQ Absolute tandem quadrupole mass spectrometer. The goal is to access previously undetectable molecular targets, accelerate large-scale imaging studies, simplify quantification, and improve sustainability in laboratory operations.

Methods and Instrumentation

A targeted multiple reaction monitoring (MRM) approach was implemented directly on tissue sections using DESI XS for soft ionization and Xevo TQ Absolute for high-sensitivity detection. Data acquisition was supported by High Definition Imaging (HDI 1.7) software and a suite of MSI MicroApps, including Segmentation Browser, Analyte Browser, and Real-Time Viewer. Quantitative workflows employed the MSI Quantify MicroApp to extract region-of-interest intensities, apply normalization, and generate calibration curves.

Main Results and Discussion

The targeted system exhibited at least fivefold greater sensitivity compared to high-resolution MS imaging, enabling visualization of low-level lipids in mouse brain and comprehensive mapping of the drug gefitinib and 16 metabolites in mouse liver over multiple time points. The integration of HDI and MicroApps facilitated efficient data segmentation, spectral annotation, and troubleshooting. Quantification workflows demonstrated linear dynamic range and accurate calibration of MSI data, highlighting the method's robustness and reliability.

Benefits and Practical Applications

The described targeted MS imaging approach offers:

• Enhanced detection limits for known biomarkers, APIs, and metabolites
• High-throughput analysis of large sample cohorts with reproducible results
• Simplified data management through reduced file sizes and focused MRM datasets
• Seamless integration into multimodal imaging pipelines
• Reduced operational costs and environmental impact with lower power, gas consumption, and heat output

Future Trends and Applications

Advances in ion mobility integration, full-spectrum DESI and MALDI combinations, and expanded software capabilities are expected to further enhance molecular specificity and throughput. Emerging applications include spatial omics in precision medicine, real-time intraoperative diagnostics, environmental surface analysis, and quality control in industrial settings.

Conclusion

The combination of DESI XS and Xevo TQ Absolute establishes a powerful targeted MS imaging platform that delivers unprecedented sensitivity, selectivity, and efficiency. This workflow enables reliable spatial quantification and rapid data interpretation, unlocking new possibilities in research and applied sciences.

Reference

• No formal literature references were cited in the original document.