Enhancing Hydroxyl Metabolite Analysis through In Situ Derivatization-Enabled Desorption Electrospray Ionization-Mass...

Area of Science:

• Analytical Chemistry
• Metabolomics
• Mass Spectrometry Imaging

Background:

• Hydroxyl metabolites are crucial but difficult to detect in metabolomics due to ionization challenges.
• Previous work introduced BBII for enhanced hydroxyl metabolite sensitivity in LC-MS.

Purpose of the Study:

• To develop a novel method for in situ hydroxyl metabolite detection using BBII derivatization integrated with DESI.
• To enhance sensitivity and enable spatial visualization of hydroxyl metabolites in biological samples.

Main Methods:

• Incorporating BBII directly into the DESI spray solvent for instantaneous derivatization.
• Applying the BBII-DESI method to hydroxyl metabolite reference standards and mouse brain tissue sections for MSI.
• Utilizing the unique boron isotopic pattern of BBII for metabolite identification.

Main Results:

• Achieved 1.8- to 17.2-fold signal increases for hydroxyl metabolite standards.
• Made previously undetectable metabolites like glucose and estradiol readily observable.
• Successfully visualized spatial distributions of glucose and cholesterol in mouse brain tissue using MSI.

Conclusions:

• BBII-DESI significantly enhances hydroxyl metabolite detection and spatial visualization.
• The method unveils the "dark metabolome" of hydroxyl compounds, providing new metabolic insights.
• This approach advances ambient ionization techniques for minimal-preparation, high-throughput biological analysis and biomarker discovery.