PNNL

Abstract

The coupling of Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with electrospray ionization (ESI) has advanced the analysis of large byopolymers. In this work the combination of need for high throughput protein characterization (e.g. for rapid "proteome" analyses), high-performance capillary liquid chromatography (HPLC) with FTICR mass spectrometry and external ion accumulation has been shown to increase in both sensitivity and analysis duty cycle. Instrument versatility is further improved by ion pre-selection followed by ion accumulation in an external linear quadrupole ion trap. The interface was tested with a 3.5 tesla FTICR mass spectrometer and evaluated with a number of peptides and proteins whose molecular weights ranged from 500 Da to 66 kDa. A significant increase in the sensitivity, duty cycle and dynamic range over that of the previously used accumulated trapping was achieved, exhibiting a detection limit of ~10 zmol (~6000 molecules) for smaller proteins such as cytochrome c. Capillary LC external accumulation interface with FTICR was successfully applied for the study of the tryptic digest of mouse proteome.