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Shift in Frequency NMR

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  1. Feb 21, 2015 #1
    1. The problem statement, all variables and given/known data
    In an NMR spectrum a CH2 group has a peak centred at 9.81 ppm. What is the shift in Larmor frequency of the protons from that of an unshielded proton if the spectrometer magnetic field is 9.4 T? The magnetogyric ratio of an unshielded proton is γH = 26.75 × 107 rad s-1T-1

    2. The attempt at a solution
    So 26.75 × 107 rad s-1T-1 x 9.4 T = 2.51 x 109 rad s-1
    x 0.159155 = 4.00 x 109 Hz
    /106 = 400 MHz

    Then I don't really know what to do
    Chemical shift = v(sample)-v(reference)/v(reference)
    9.81ppm = 106 x (v(sample)- 4 x 10-9/4 x 10-9)
    3924 = 106 x (v(sample) x 10-6 - 400)
    4324 MHz for the sample frequency which I'm sure is wrong.
     
  2. jcsd
  3. Feb 24, 2015 #2

    Astronuc

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    Staff: Mentor

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