Reference%20Materials

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Reference Materials

• McLafferty Turacek, Interpretation of Mass
  Spectra, 4th Ed. (University Science Books)
• NIST http//webbook.nist.gov/chemistry (online
  spectra)
• University of Sheffield http//www.shef.ac.uk/c
  hem/chemputer (Isotope envelope calculator)

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A generic mass spectrometer
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Magnetic Mass Filtration
m/z 4.82 x 10-5 B2r2/V m Ion mass z Ion
charge B Magnetic field strength (Gauss) r
Radius of ion path (cm) V Ion accelerating
voltage (volts)
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A typical spectrum
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Isotopic Abundances for Important Elements
C 12C 100 13C 1.1 14C lt0.1
N 14N 100 15N 0.37
H 1H 100 2H 0.015 3H lt0.001
Cl 35Cl 100 37Cl 32.5
Br 79Br 100 81Br 98
O 16O 100 17O 0.04
18O 0.20
Si 28Si 100 29Si 5.1 30Si
3.4
S 32S 100 33S 0.8 34S
4.4
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Classification of elements
A A1
A2 H C
O F (19F) N
Si P (31P)
S I (127I)
Cl
Br
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Contribution to (M1) vs. Number of Carbons
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Halogen Patterns
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Example 1
12,42 13,17 14,17 15,1 26,168 27,999 28,17
29,1
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Example 2
12,5 13,9 14,21 15,466 16,6 46,14 47,25
48,11 79,63 80,16 81,63 82,16 91,68 92,40
93,209 94,999 95,149 96,942 97,11
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Calculating unsaturations
(R D) x ½ y ½ z 1 for CxHyNzOn
Cl, Br, F H S O P N Si C
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Diethyl Ether
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Triethylamine
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Decane
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2,7-Dimethyloctane
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Hexylbenzene
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Generation of the m/z 91 peak
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Ephedrine
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Methamphetamine
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Phentermine
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THC (Tetrahydrocannabinol)
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MDMA (Ecstasy)