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NMR Spectroscopy (Griffith)

  • Page ID
    296065
  • In-Class Exercise

    NMR – Larmor Frequency and Saturation:

    1. Calculate the Larmor frequency for the 1H nucleus in an NMR with a Bo = 4.69 Tesla.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    1. What is the ratio between 1H nuclei occupying the β versus α states in the 500 MHz Willamette NMR at 25 °C?

     

     

     

     

     

     

     

     

     

     

     

    Constants/Tables:

    Nucleus Magnetogyric Ratio, radian T-1 s-1 Isotopic Abundance, % Relative Sensitivitya Absorption Frequency, MHzb
    1H 2.6752 × 108  99.98 1.00  200.00
    13C 6.7283 × 107   1.11 0.016  50.30
    19F 2.5181 × 108 100.00 0.83  188.25
    31P 1.0841 × 108 100.00 0.066  81.05

    aAt constant field for equal number of nuclei.
    bAt a field strength of 4.69 T.
    © 2007 Thomson Higher Education

    From: Principles of Instrumental Analysis, 6th Edition, D.A. Skoog, F.J. Holler, S.R. Crouch, 2007, Thomson Brooks/Cole

     

    h = 6.626 × 10-34 J s

    k = 1.38 × 10-23 J K-1

    c = 2.997 × 108 m/s (in a vacuum)

    1T = 104 G = 1 kg s-2 A-1 = 1 V s m-2

     

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