AEROSOL MATRIX-ASSISTED LASER-DESORPTION IONIZATION MASS-SPECTROMETRY.1. EFFECT OF SOLVENT ON ION SIGNAL

The effects of methanol, ethanol, propan-2-ol and acetonitrile on the aerosol matrix-assisted laser desorption/ionization (MALDI) ion signal of bradykinin, bovine insulin and myoglobin were examined. The effect of these solvents mixed with water was also studied. The aerosol MALD I ion signal for each analyte depends on the solvent, but the solvent dependence is different for the matrices 4-nitroaniline and alpha-cyan o-4-hydroxycinnamic acid. The data suggest that matrix-analyte-solvent interactions are an important consideration for the aerosol MALDI ion signal. It appears that the ion signal is the result of a competition between solvent polarity and volatility. The solvent polarity affects matrix-analyte interactions whereas solvent volatility affects the ae rosol drying process.