Database of free solution mobilities for 276 metabolites

Area of Science:

• Analytical Chemistry
• Metabolomics
• Biochemistry

Background:

• Existing metabolite databases lack electrophoretic mobility data.
• This data gap results in unidentified compounds, annotated as
• features
• in electrophoretic-based metabolomics studies.

Purpose of the Study:

• To generate electrophoretic mobility values for common metabolites.
• To improve metabolite identification in capillary electrophoresis (CE) studies.

Main Methods:

• Analyzed 460 metabolites using capillary zone electrophoresis (CZE) coupled with electrospray mass spectrometry (ESI-MS).
• Employed a sequential injection method with six compounds per run.
• Utilized an uncoated fused silica capillary at 20°C with a formic acid and methanol background electrolyte, coupled to an ion trap MS via a nanospray interface.

Main Results:

• Generated mobility values for 276 metabolites (60% success rate) with high precision (average standard deviation of 0.01 × 10⁻⁸ m²V⁻¹s⁻¹).
• Demonstrated effective separation of cationic, anionic, and neutral compounds.
• Identified neutral compounds as the primary group with detection issues, likely due to capillary adsorption or poor ionization.

Conclusions:

• Successfully generated a valuable dataset of electrophoretic mobility values for common metabolites.
• This dataset will significantly enhance the identification of unknown features in CE-based metabolomics.
• Highlights challenges in detecting neutral metabolites, suggesting areas for future methodological improvements.