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Matrix‐free infrared soft laser desorption/ionization
Author(s) -
Rousell David J.,
Dutta Sucharita M.,
Little Mark W.,
Murray Kermit K.
Publication year - 2004
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.706
Subject(s) - soft laser desorption , matrix assisted laser desorption electrospray ionization , chemistry , atmospheric pressure laser ionization , desorption , mass spectrometry , ionization , analytical chemistry (journal) , laser , far infrared laser , reflectron , matrix assisted laser desorption/ionization , silicon , ambient ionization , ion source , desorption electrospray ionization , photoionization , chemical ionization , optics , time of flight mass spectrometry , ion , chromatography , adsorption , organic chemistry , physics
Infrared soft laser desorption/ionization was performed using a 2.94 µm Er : YAG laser and a commercial reflectron time‐of‐flight mass spectrometer. The instrument was modified so that a 337 nm nitrogen laser could be used concurrently with the IR laser to interrogate samples. Matrix‐assisted laser desorption/ionization (MALDI), laser desorption/ionization and desorption/ionization on silicon with UV and IR lasers were compared. Various target materials were tested for IR soft desorption ionization, including stainless steel, aluminum, copper, silicon, porous silicon and polyethylene. Silicon surfaces gave the best performance in terms of signal level and low‐mass interference. The internal energy resultant of the desorption/ionization was assessed using the easily fragmented vitamin B 12 molecule. IR ionization produced more analyte fragmentation than UV‐MALDI analysis. Fragmentation from matrix‐free IR desorption from silicon was comparable to that from IR‐MALDI. The results are interpreted as soft laser desorption and ionization resulting from the absorption of the IR laser energy by the analyte and associated solvent molecules. Copyright © 2004 John Wiley & Sons, Ltd.