Elemental Sulfur as a Versatile Low-Mass-Range Calibration Standard for Laser Desorption Ionization Mass Spectrometry

Facile generation of series of singly charged radical anions (S-n(-center dot); n = 1-15) and cations (S-n(+center dot); n = 2-11) by direct laser ionization renders elemental sulfur an excellent material for the low-mass-region calibration of time of flight (TOF) mass spectrometers. Upon irradiation by a 337-nm UV laser, elemental sulfur undergoes facile ionization without the need of an additional laser-absorbing matrix. An intense and evenly spaced set of peaks is obtained in both modes. (J Am Soc Mass Spectrom 2010, 21, 112-116) (C) 2010 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry