A novel interface for on-line coupling of liquid capillary chromatography with matrix-assisted laser desorption/ionization detection

A novel interface has been developed which should allow the direct on-line coupling of liquid capillary chromatography with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry detection. The interface employs continuous analyte/matrix co-crystallization onto a porous frit installed at a capillary end which is used as the target for MALDI. After separation, the analyte effluent is premixed with the MALDI matrix solution and introduced into the interface. The analyte/matrix mixture is co-crystallized onto the frit surface in the vacuum environment of the mass spectrometer. Continuous matrix/analyte crystallization and interface regeneration is accomplished by a combination of solvent flushing and laser ablation. The memory effect is negligible over a dynamic range of ca. 200. Several applications, including analysis of small peptides and combination with gel permeation chromatography (GPC), have indicated that the on-line MALDI interface does not sacrifice chromatographic or mass spectral resolution, and have demonstrated the possibility of a reliable LC-MALDI system. Copyright 1999 John Wiley & Sons, Ltd.