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3. A gaseous sample compound is injected into the mass spectrometer.

4. It is bombarded by high energy electrons from an electron gun.

5. A molecular ion is produced. It contains an unpaired electron so it is also a free radical.

7. If a covalent bond in the molecular ion breaks, fragmentation happens.

8. Fragmentation produces an ion and a free radical.

9. Only the ion is attracted to the charged plates in the mass spectrometer and detected subsequently.

10. End of section one, return to menu by clicking "Reset".

11. This is the displayed formula of propanone, CH 3 COCH 3. What might happen to propanone in the mass spectrometer?

12. A molecular ion could form. This will be detected by the mass spectrometer and produce a peak in the mass spectrum.

13. What is the mass/charge ratio, m/z, of the molecular ion?

18. The relative formula mass, M r, is 58.

19. The charge on the ion is +1, so the m/z ratio is 58÷1=58.

20. The molecular ion will produce a peak in the mass spectrum here.

21. A covalent bond in the molecular ion may break causing fragmentation.

22. Fragmentation could produce the carbocation, CH 3 +. This will give a peak in the mass spectrum.

23. The free radical, COCH 3.,will not give a peak in the mass spectrum.

24. What is the mass/charge ratio, m/z, of the CH 3 + ion?

27. The relative formula mass, M r, is 15.

28. The charge on the ion is +1, so the m/z ratio is 15÷1=15.

29. The CH 3 + ion will produce a peak in the mass spectrum here.

30. Fragmentation could also produce a methyl radical, CH 3. This will not give a peak in the mass spectrum.

32. The COCH 3 + ion will give a peak in the mass spectrum.

33. What is the mass/charge ratio, m/z, of the COCH 3 + ion?

38. The relative formula mass, M r, is 43.

39. The charge on the ion is +1, so the m/z ratio is 43÷1=43.

40. The COCH 3 + ion is the most stable fragment and forms the base peak.

41. These are the major peaks in the mass spectrum of propanone. There will be others from further fragmentation.

42. End of section two, return to menu by clicking "Reset".

43. This table summarises some common fragments lost because of fragmentation or seen in mass spectra.

44. End of section three, return to menu by clicking "Reset".