Application of microcalorimeter energy measurement to biopolymer mass spectrometry

We have performed electrospray ionization mass spectrometry using a magnetic-sector mass spectrometer of proteins, detecting the ions with a normal-insulator-superconductor microcalorimeter detector. We emphasize the measurement of ion-impact energy as a way to obtain extra information that is unavailable in normal mass spectrometry. Energy measurements are used to discriminate against erroneous ion-strikes, to resolve ambiguities that cannot be resolved by normal mass spectrometry, and to illustrate some of the performance limits of the current detector design.