Evaluation of pyridoindoles, pyridylindoles and pyridylpyridoindoles as matrices for ultraviolet matrix- assisted laser desorption/ionization time-of-flight mass spectrometry

In an effort to gain an understanding of the processes governing ultraviole t matrix-assisted laser desorption/ionization (UV-MALDI), direct comparison was made of the mass spectra of proteins, carbohydrates and synthetic poly mers (polyethylene glycol, polyester and polyamide) by using pyridylindoles , pyridoindoles and pyridylpyridoindoles as UV (337 nm)-MALDI-TOFMS matrice s in positive and negative ion mode. In order to study the combined effect of the indole N-H and the pyridine nitrogen of the MALDI matrix on the deso rption/ionization process in MALDI, compounds were selected that include ei ther or both of these functions in their structure. Within the compounds st udied only those that possess simultaneously both functions in a 1,4-relati on behave as very good matrices for proteins. These compounds also work as matrices for some carbohydrates and synthetic polymers used as analytes in the present study. Some of the compounds were also found to be useful for t he post-source decay (PSD) analysis of cyclodextrins in positive and negati ve ion mode. In several cases we also examined the matrix behavior of the c orresponding N-methylindole derivatives. Copyright (C) 2001 John Wiley & So ns, Ltd.