Imaging mass spectrometry for examining localization of polymeric composition in matrix‐assisted laser desorption/ionization samples

The localization of polymeric composition in samples prepared for matrix‐assisted laser desorption/ionization (MALDI) analysis has been investigated by imaging mass spectrometry. Various matrices and solvents were used for sample spot preparation of a polybutyleneglycol (PBG 1000). It was shown that in visibly homogeneous spots, prepared using the ‘dried droplet’ method, separation between matrix and polymer takes place. Moreover, using α‐cyano‐4‐hydroxycinnamic acid (CCA) as matrix and methanol as solvent molecular mass separation of the polymer homologues in the spots was detectable. In contrast to manually spotted samples, dry spray deposition results in homogeneous layers showing no separation effects. Copyright © 2009 John Wiley & Sons, Ltd.