Reference Materials McLafferty & Turacek, “Interpretation of Mass Spectra”, 4 th Ed. (University...
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Transcript of Reference Materials McLafferty & Turacek, “Interpretation of Mass Spectra”, 4 th Ed. (University...
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/~chem/chemputer (Isotope envelope calculator)
A generic mass spectrometer
Magnetic Mass Filtration
m/z = 4.82 x 10-5 B2r2/V
m Ion massz Ion chargeB Magnetic field strength (Gauss)r Radius of ion path (cm)V Ion accelerating voltage (volts)
A typical spectrum
Isotopic Abundances for Important Elements
H: 1H 100 2H 0.015 3H <0.001
C: 12C 100 13C 1.1 14C <0.1
N: 14N 100 15N 0.37
O: 16O 100 17O 0.04 18O 0.20
Cl 35Cl 100 37Cl 32.5
Br: 79Br 100 81Br 98
Si: 28Si 100 29Si 5.1 30Si 3.4
S: 32S 100 33S 0.8 34S 4.4
Classification of elements
A A+1 A+2
H C OF (19F) N SiP (31P) SI (127I) Cl
Br
Contribution to (M+1) vs. Number of Carbons
Halogen Patterns
Example 1
12,42 13,17 14,17 15,1 26,16827,999 28,17 29,1
Example 2 12,5 13,9 14,21 15,466 16,646,14 47,25 48,11 79,63 80,1681,63 82,16 91,68 92,40 93,20994,999 95,149 96,942 97,11
Calculating unsaturations
(R + D) = x – ½ y + ½ z + 1for CxHyNzOn
Cl, Br, F =HS = OP = NSi = C
Diethyl Ether
Triethylamine
Decane
2,7-Dimethyloctane
Hexylbenzene
Generation of the m/z = 91 peak
Ephedrine
Methamphetamine
Phentermine
THC (Tetrahydrocannabinol)
MDMA (Ecstasy)