1. Mass Spectrometry  Determine the Molecular Mass of organic compounds.  Determine the Molecular Formula of organic compounds.  Sometime identified the functional groups in organic compounds. The main use of Mass in organic chemistry is: 1

2. Mass Spectrometer Sample Inlet system Ionization Chamber Mass Analyzer Detector 2

3. There are three kinds each of which we will consider each of these separately: Mass Spectrum  Molecular ion  Fragments  Natural abundance of isotopes 3

4. Molecular ion Separate the Ions according to their Mass-to-Charge ratios (m/e) 4

5. Cyclohexane 5

6. n-Octane 6

7. 2-Methylpentane 7

8. Isotopic Abundance 81 Br 8

9. Mass Spectrum with Bromine 9

10. Mass Spectrum with Chlorine 10

11. طيف الكتلة للمركبات العضوية الشائعة Hydrocarbons m/e = 43 m/e = 29 m/e = 43 m/e = 57 11

12. Mass Spectra of Alkanes 12

13. Mass Spectra of Alkanes More stable carbocations will be more abundant. 13

14. Cycloalkane m/e = 42 14

15. m/e = 56 m/e = 69 m/e = 41 Cycloalkane 15

16. Alkene allylic cleavage m/e = 41 16

17. Cycloalkene m/e = 54 17

18. Alkyne β- cleavage m/e = 39 18

19. Aromatic Hydrocarbons 19

20. Aldehydes and Ketones Aldehyde α - cleavage 20

21. Ketone α - cleavage 21

22. McLafferty rearrangment 22

23. Carboxylic acids and Deriv. 23

24. Amines β - cleavage 24

25. Alcohols β - cleavage 25

26. Phenol 26