KCS

A newly installed 12 Tesla FTMS in KRISS is equipped with ECD capabilities useful for top-down analysis of large proteins. In particular, the ECD functions are realized using a hot dispenser cathode instead of conventional EI (electron impact) filaments. In general, this cathode generates a large flux of thermal electrons on the hot surfaces that are necessary for ECD fragmentations. For the use of this cathode for ECD MS, the following precautions have been expressed: the introduction of the dispenser cathode with a large surface area nearby the ICR cell may heat up the molecular ions through blackbody radiations. Here, we seek to provide a clear answer using a molecular thermometer of ubiquitin 7+ ions as well as phosphopeptides.