MERCAPTOBENZOTHIAZOLES - A NEW CLASS OF MATRICES FOR LASER-DESORPTIONIONIZATION MASS-SPECTROMETRY

We report 2-mercaptobenzothiazole (MET) and its analogs as a class of new matrices for matrix-assisted laser desorption mass spectrometry (M ALDI-MS) at 337 nm. MBT has been used successfully for the desorption of proteins up to 100,000 u. A comparison with sinapinic acid and alph a-cyano-4-hydroxycinnamic acid indicates that MBT provides the same le vel of sensitivity and resolution, but offers the advantage of higher tolerance to sample contaminants such as ionic detergents. 5-Chloro-2- mercaptobenzothiazole (CMBT), an analog of MET, has been found not onl y effective for the analysis of peptides, low-mass proteins, and glyco lipids, but also superior to conventional matrices for the analysis of muropeptides and at least some oligosaccharides. CMBT also exhibits e xcellent experimental reproducibility of MALDI-MS results owing to the homogeneous crystallization of the analyte/matrix mixture over the en tire sample surface area. Finally, all five mercaptobenzothiazoles stu died in this work are shown to be well suited for synthetic polymer an alysis. (C) 1997 American Society for Mass Spectrometry