Ultraviolet laser induced hydrogen transfer reaction: study of the first step of MALDI in-source decay mass spectrometry.
The early mechanisms of matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) are described herein. MALDI-ISD is initiated by the hydrogen transfer from excited matrix molecules to the carbonyl oxygen of the peptide backbone, which is followed by a radical-induced cleavage, producing the c'/z• fragment pair. As expected, the use of 2,5-DHB or 1,5-DAN was efficient to induce MALDI-ISD, and the strongest intensity of MALDI-ISD fragments was observed when laser shots were performed on matrix crystals. In contrast, the hydrogen radical transfer reaction was suppressed by using ionic liquid and amorphous structure of 2,5-DHB and 1,5-DAN mixture as a matrix. Our results suggest that the hydrogen transfer occurs on the matrix crystal during the dissipation of the laser energy and before desorption, following ISD fragments formed in the MALDI plume.
Chemistry Department and GIGA-R, Mass Spectrometry Laboratory, University of Liege, Belgium. dasakawa@yokohama-cu.ac.jp
Daiki
D
Asakawa
David
D
Calligaris
Nicolas
N
Smargiasso
Edwin
E
De Pauw
D015081:2-Naphthylamine / Q000031:analogs & derivatives / Q000737:chemistry; D002116:Calcitonin / Q000737:chemistry; D005841:Gentisates / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014466:Ultraviolet Rays
D005841:Gentisates; D010455:Peptides; C510889:1,5-diaminonaphthalene; D006859:Hydrogen; D002116:Calcitonin; D015081:2-Naphthylamine; C010925:2,5-dihydroxybenzoic acid