APPLICATION OF LIQUID MATRIX-ASSISTED LASER DESORPTION IONIZATION 4-SECTOR TANDEM MASS-SPECTROMETRY FOR THE ANALYSIS OF SPIDER TOXIN ACYLPOLYAMINES/

We have applied a recently proposed liquid matrix-assisted laser desor ption/ionization (LMALDI) method on a 4-sector tandem mass spectromete r equipped with an array detector at MS-2. Although the ionizing laser beam is pulsed, the use of a liquid matrix can prolong the analyte io n current over 20 min without moving the laser irradiation spot and pr ovide an ion current that is stable enough to acquire both mass spectr a and collision-induced dissociation (CID) spectra. Product ions, whic h originate from chemical background overlapping the precursor ions, w ere not observed in the MALDI-CID spectra of acylpolyamines (below m/z 1000) unlike the case with FAB spectra. These LMALDI-CID spectra are shown to provide detailed structural information of equivalent or high er equality compared with spectra obtained by using LAP-high energy CI D conditions on a 4-sector tandem mass spectrometer. The advantages of the LMALDI-CID method compared with FAB-CID is discussed, together wi th the structure determination of new glutaminergic nerve blocker acyl polyamines obtained from Nephila madagascariencis spider venom. (C) 19 97 by John Wiley & Sons, Ltd.