Problem 6.3

a) How can you calculate the number of rings plus double bonds (r+d) based on a molecular formula?

b) Apply the r+d algorithm to the compounds below.

Molecular composition

C3H8

C6H12O2

C6H11NO

C32H25N3O2S

C8H20N2

C7H9N

C3H6BrN

C9H11ClN4O2

C17H32Cl2

r+d = …

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c) Collect criteria for the recognition of molecular ions from EI mass spectra.

d) Some neutral losses occurring from molecular ions are very frequent and can be reliably assigned to certain structural features. Try to assign the following neutral losses:

Neutral loss [u]

1

15

17

18

28

29

31

35

45

Reasonable formula …

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