REVERSE-PHASE LIQUID-CHROMATOGRAPHY ELECTROSPRAY-IONIZATION FOURIER-TRANSFORM MASS-SPECTROMETRY IN THE ANALYSIS OF PEPTIDES

Electrospray ionization (ESI) in combination with Fourier-transform mass spectrometry (FTMS) gives both highly accurate mass analysis of peptides with external calibration and high resolution for charge-state determination of an ion from the naturally occurring isotopic peaks. Liquid chromatographic (LC) separation of peptides is important for the analysis of complex mixtures. High-resolution, high accuracy measurement of the molecular ions of the mix of peptides has been achieved with LC/ESI-FTMS. Examples are given to show both the reproducibility of mass accuracy over replicate analyses and to show the utility of broadband analysis of a gradient separation of peptides. The high mass accuracy and resolution of FTMS was uncompromised for the direct analysis of chromatography peaks.