Mass Spectroscopy Flashcards
The energy of the electrons is
1600 kcal (70 eV)
The tallest peak in the mass spectrum is called the
base peak
Structure of MS
Inlet system
ion source
mass analyzer
detector
signal processor
Readout
The two main forms of MS are
electrospray
MALDI
Bromine (m+2) peak will be
50/50
Nitrogen will have
an odd number for MW (if odd # N)
an even number for MW (if even # N)
If the (m+2) peak is 1/3 as large as the M+ peak then you have
Cl
Loss of methyl equals
M+ - 15
Loss of ethyl
M+ - 29
Loss of propyl
M+ - 43
Loss of butyl
M+ - 57
Aromatics have a peak at
77
What is Raman spectroscopy?
small fraction of radiation scattered by certain molecules
What is Stokes?
emission energy is less than excitation energy
What is Anti-Stokes?
emission energy is more than excitation energy
The instrumentation for Raman
laser source
sample
wavelength selector
radiation transducer
data system
Symmetric stretching is
Raman inactive
Antisymmetric stretching is
Raman active
To be Raman active there must be
a change in polarizability
