Benefits of 2.94 mu m infrared matrix-assisted laser desorption/ionizationfor analysis of labile molecules by Fourier transform mass spectrometry

A 2.94 mu m Er:YAG laser was used together with a commercial Fourier transf orm mass spectrometer to study labile biomolecules, The combination has sho wn superior performance over conventional 337 nm ultraviolet matrix-assiste d laser desorption/ionization (UV-MALDI) Fourier transform mass spectrometr y (FTMS), especially for the analysis of peptides with post-translational m odifications, With succinic acid as a matrix, the sensitivity of the single -shot analysis was increased by an order of magnitude to the law femtomole level, with significantly less fragmentation observed, Intact molecular ion s of a range of O-glycosylated and sulfated peptides were detected, Urea wa s found to induce even less fragmentation, although at the expense of the t otal ion yield. Molecular ions of a noncovalent complex (vancomycin + diace tyl-L-Lys-D-Ala-D-Ala) have been observed for the first time in MALDI-FTMS. 2.94 mu m infrared (IR) MALDI also produced abundant molecular ions of a r ange of nonbiological samples, including C-60 and C-70 fullerenes as web as dimetal coordination complexes, Copyright (C) 2000 John Whey & Sons, Ltd.