Sheathless capillary electrophoresis-mass spectrometry for anionic metabolic profiling

Area of Science:

• Analytical Chemistry
• Metabolomics
• Mass Spectrometry

Background:

• Capillary electrophoresis coupled online to mass spectrometry (CE-MS) is a powerful analytical technique.
• Existing CE-MS methods face challenges in sensitivity and efficiency for anionic metabolic profiling.
• Sheathless interface designs offer potential improvements in analyte transfer and detection.

Purpose of the Study:

• To evaluate the performance of a sheathless CE-MS system for anionic metabolic profiling.
• To assess analytical parameters including separation efficiency, repeatability, and limits of detection (LODs).
• To demonstrate the method's applicability to biological samples, such as glioblastoma cell line extracts.

Main Methods:

• Utilized a sheathless porous tip sprayer for online coupling of capillary electrophoresis (CE) to mass spectrometry (MS).
• Employed negative ion mode MS detection with 10% acetic acid (pH 2.2) as the background electrolyte (BGE).
• Analyzed a representative metabolite mixture and glioblastoma cell line extracts, evaluating parameters like plate numbers, migration time, peak area repeatability, and LODs.

Main Results:

• Achieved high separation efficiency with plate numbers ranging from 60,000 to 400,000.
• Demonstrated excellent repeatability for migration times (RSDs < 2%) and peak areas (RSDs < 11%).
• Obtained significantly improved LODs (10-200 nM, 0.4-4 fmol) – at least a tenfold increase compared to conventional CE-MS.

Conclusions:

• Developed a highly efficient and sensitive sheathless CE-MS method for anionic metabolic profiling.
• The method effectively separates and analyzes critical metabolites, including those poorly retained in reversed-phase LC.
• The developed methodology is versatile and can be adapted for cationic metabolic profiling by polarity switching.