Application of microcalorimeter energy measurement to biopolymer mass spectrometry

We have performed electrospray ionization mass spectrometry using a magneti c-sector mass spectrometer of proteins, detecting the ions with a normal-in sulator-superconductor microcalorimeter detector. We emphasize the measurem ent of ion-impact energy as a way to obtain extra information that is unava ilable in normal mass spectrometry, Energy measurements are used to discrim inate against erroneous ion-strikes, to resolve ambiguities that cannot be resolved by normal mass spectrometry, and to illustrate some of the perform ance limits of the current detector design.