Poster presentation from the American Society for Mass Spectrometry 2026 annual conference.
Microchip CE-MS has demonstrated impressive performance for the analysis of polar metabolites. The most successful method uses glass microfluidic devices coated with a neutral polymer surface chemistry to suppress electroosmotic flow (ZipChip, Repligen Corp). Fast and highly efficient separations can be achieved, but only molecules that carry a positive charge at pH 2.3 can be analyzed due to the reliance on electrophoretic migration to move analytes. Here we demonstrate the ability to improve the coverage of this method by using pressure-driven flow (PDF) to push neutral and weakly charged analytes through the separation channel. Crucially the method does not degrade the separation of the more highly mobile analytes, and it can be run without modification to commercially available systems.