MASS SPECTROSCOPY

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MASS SPECTROSCOPY
R W Grime Ripon Grammar School
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(No Transcript)
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butane CH3CH2CH2CH3
C4H10 ? C4H10. e m/z 58
C4H10. ? CH3CH2CH2 .CH3
m/z 43
C4H10. ? CH3CH2 .CH2CH3 m/z 29
CH3CH2CH2

• Peak with greatest m/z value MOLECULAR ION
• Other peaks due to molecular ion breaking into
  fragments

CH3CH2
C4H10.
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butanone CH3CH2COCH3
Mr 72
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methyl butanoate CH3CH2CH2COOCH3
Mr 102
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bromomethane CH3Br
79Br81Br 11
CH381Br.
CH379Br.
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chloroethane CH3CH2Cl
35Cl37Cl 31
CH3CH235Cl.
CH3CH237Cl.
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• HIGH RESOLUTION MASS SPECTROSCOPY

• Molecular ion formed M ? M. e
• m/z value for M. gives the Mr.
• High resolution measures m/z to enough accuracy
  to find the molecular formula.
• High resolution Mr gives molecular formula.

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• HIGH RESOLUTION MASS SPECTROSCOPY

e.g. The following compounds all have Mr 60 at
low resolution but at high resolution their Mrs
are different if they have a different molecular
formula. CH3COOH 60.02112 molecular formula
C2H4O2 NH2CONH2 60.03235 molecular formula
CH4N2O CH3CH2CH2OH 60.05751 molecular formula
C3H8O CH3CH(OH)CH3 60.05751 molecular formula
C3H8O