Thermo Finnigan LLC

Helene L Cardasis

William M McGee

Ping F Yip

James L Stephenson, Jr

The present disclosure establishes new dissociation parameters that may be used to determine the collision energy (CE) needed to achieve a desired extent of dissociation for a given analyte precursor ion using collision cell type collision-induced dissociation. This selection is based solely on the analyte precursor ion's molecular weight, MW, and charge state, z. Metrics are proposed that may be used as a parameter for the 'extent of dissociation', and then predictive models are developed of the CEs required to achieve a range of values for each metric. Each model is a simple smooth function of only MW and z of the precursor ion. Coupled with a real-time spectral deconvolution (m/z to mass) algorithm, methods in accordance with the invention enable control over the extent of dissociation through automated, real-time selection of collision energy in a precursor-dependent manner.

Automated determination of mass spectrometer collision energy

Applications of ion-ion reaction chemistry are disclosed in which proton transfer reactions (PTR) combined with higher-collision-energy dissociation (HCD) are used to (1) simplify complex mixture analysis of samples introduced into a mass spectrometer, and (2) improve resolution and sensitivity for the analysis of large proteins in excess of 50 kDa by removing charge, reducing the collisional cross section, and, in several cases, enhancing the sequence coverage obtained.

Growing community of inventors

Mountain View, CA, United States of America

Helene L Cardasis