1. Compound is first vaporized and converted into ions, which are then separated and detected.
Electron Impact (EI) Mass Spectrometry 1

2. The Mass Spectrum
It is a graph of the relative abundance of each positively charged fragment plotted against its m/z value. Results may also be presented in tabular form. 2

3. 3

4. 4

5. 5

6. 6

7. 7

8. Example 1:
Determine the molecular formula for a compound that gives the following mass spectral data:
m/z
intensity 86
100.0
(M+) 87
5.6 88
0.4 8

9. Example 2:
Determine the molecular formula for a compound that gives the following mass spectral data:
m/z
intensity 43
79.0 44
100.0
(base) 72
73.0
(M+) 73
3.3 74
0.2 9

10. Fragmentation Patterns of Hydrocarbons16

11. 17

12. Fragmentation Patterns of Alkyl and Aryl Halides18

13. 19