Controlling matrix suppression for matrix-assisted laser desorption/ionization analysis of small molecules

The need for high-throughput methodologies providing both qualitative and quantitative information has grown substantially in the pharmaceutical laboratory in recent years. Currently, tandem mass spectrometry (MS/MS) using quadrupole technology offers analysis in the minutes time scale. The use of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) offers the advantage of speed and automation and enables analysis in the seconds time scale with accurate mass capabilities that are not typically found in quadrupole MS/MS. However, one of the limitations of MALDI for the analysis of small molecules is the abundance of interfering matrix peaks in the low molecular weight region of the mass spectrum. Described herein is an evaluation of a pre-prepared MALDI target plate that has been coated with a thin layer of alpha-cyano-4-hydroxycinnamic acid (CHCA) and nitrocellulose. This modified plate has been shown to suppress or eliminate CHCA matrix signals without any significant loss of analyte sensitivity when compared with analysis of the same sample using an unmodified target plate. Copyright (C) 2004 John Wiley Sons, Ltd.