The molecular ion region in the mass spectrum of a large molecule, such as a protein, consists of a cluster of peaks differing by 1 Da. This pattern occurs because a molecule with many atoms has a high probability of containing one or several atoms of 13 C, 15N, 180, 2H and 34 S. The probability of finding a molecule with only 12C, 14N, 160, 'H and 32S may be so small that the nominal molecular ion is not observed. The electrospray mass spectrum of the rat protein interleukin-8 consists of a series of clusters of peaks arising from intact molecular ions with different charge. One cluster has peaks at m/z 1961.12, 1961.35, 1961.63, 1961.88, 1962.12 (tallest peak), 1962.36, 1962.60, 1962.87, 1963.10, 1963.34, 1963.59,1963.85, and 1964.09. These peaks correspond to isotopic ions differing by 1 Da. From the observed peak separation, find the charge of the ions in this cluster. Z=

The molecular ion region in the mass spectrum of a large molecule, such as a protein, consists of a cluster of peaks differing by 1 Da. This pattern occurs because a molecule with many atoms has a high probability of containing one or several atoms of 13 C, 15N, 180, 2H and 34 S. The probability of finding a molecule with only 12C, 14N, 160, 'H and 32S may be so small that the nominal molecular ion is not observed. The electrospray mass spectrum of the rat protein interleukin-8 consists of a series of clusters of peaks arising from intact molecular ions with different charge. One cluster has peaks at m/z 1961.12, 1961.35, 1961.63, 1961.88, 1962.12 (tallest peak), 1962.36, 1962.60, 1962.87, 1963.10, 1963.34, 1963.59,1963.85, and 1964.09. These peaks correspond to isotopic ions differing by 1 Da. From the observed peak separation, find the charge of the ions in this cluster. Z=

Chemistry & Chemical Reactivity

10th Edition

ISBN:9781337399074

Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Publisher:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Chapter2: Atoms Molecules And Ions

Section: Chapter Questions

Problem 100PS

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Bromine has two naturally occuring isotopes, Br-79 and Br-81, approximately 50% of each. Bromomethane will contain approximately 50% Br-79 and 50% Br-81. The mass spectrum peak for methane containing Br-79 will be referred to as the M+ (molecular ion) peak, and the peak for Br-81 will be called the M+2 peak, as Br-81 weighs two more amu than Br-79. What will be the locations of the two bromomethane peaks on the mass spectrum and what will be the approximate ratio of their heights?
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