Deducing structures from mass spectra Flashcards
1
Q
when looking at the mass spectra of one compound, we first
A
draw the different structures that the compound could have
2
Q
for mass spectra of a compound with two different structures, the steps we take to deduce which compounds have produced which spectra are:
A
- draw the different structures for the compound (displayed formulae)
- draw in possible fragmentation lines on the structures between two carbon atoms
- calculate the m/z values that each ion produced during fragmentation would produce and match these up to the peaks on the mass spectra
- the mass spectra will have different peaks, so you can see which of the compound’s isomers has split to produce the unique peaks on the graph
3
Q
the m/z value of CH3+ is
A
15
4
Q
the m/z value for OH+ is
A
17
5
Q
the m/z value for CO+ is
A
28
6
Q
the m/z value for CH3CH2+ or CHO+ are
A
29
7
Q
the m/z value for CH2OH+ is
A
31
8
Q
the m/z value for for CH3CH2CH2+ OR CH3CHCH3+ OR CH3CO+ are
A
43
9
Q
the m/z value for COOH+ or CH3CHOH+ are
A
45
10
Q
the m/z value for C4H9+ are (this represents four different structures)
A
57
11
Q
in fragmentation, the two products are
A
an ion and a neutral species
