Precision mass measurement of biomoleculesWhat kind of information can FT-ICR mass spectrometry provide?
Precision mass measurement of biomolecules
Example 1 - Determination of molecular weight of horse myoglobin
(B.E. Winger, S.A. Hofstadler, J.E. Bruce, H.R. Udseth, and R.D. Smith, J. Am. Soc. Mass Spectrom., 1993, 4, 566-577)
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Figure a represents a FT-ICR spectrum of horse myglobin using electrospray as the ionization source. Ion fragments with charge states between 10+ and 15+ are visible. Figure b shows an expansion of the mass scale of several of the charge states showing resolution of the isotopic envelope. The average mass resolution (m/D m) obtained for the 13+ charge state was 58,000. This high mass resolution allows to determine the actual charge state from the spacing of peaks in the isotopic envelope of each ion. From the theoretical isotope distribution for horse myglobin, the most abundant ion contains 11 13C isotopic contributions. Using this ion from each isotopic distribution, the authors calculated the molecula weight for horse myglobin to be 16,950.84 ± 0.04, whereas the theoretical molecular weight for the isotope ion containing 11 13C isotopes is 16,951.02. This corresponds to an error in mass measurement of 10ppm.
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Example 2
Ultra-high mass resolving power
MS-MS capability
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