[shafaifer]

Four spectrums (four isomers) of a thiol are given. I have to explain the mechanisms of fragmentation. For the peaks: 75, 61, 57 and 47 I have answered alpha-cleavage. The 56-peak I say M-34: Loss of hydrogen sulfide by alpha-cleavage. What could cause the peak at 90?

With my most sincere regards,

Yours student, Shafaifer.

[discodermolide]

Surely the peak at m/e = 90 is the molecular ion, M⁺?