Problem 10

It is not unusual to mix the molecular ion peak (M⁺) and that from the loss of hydrogen atom (M – 1). Such mistakes can be avoided considering the expected abundance of the M + 1 peak, normally due to¹³C isotope. In this case, from the mass spectrum we know that the m/z of the molecular ion is 98, and that this ion loses hydrogen and methyl radical easily since the peaks of the corresponding fragments (M-1 Æ m/z 97 and M-15 Æ m/z 83) are the ones with highest relative abundance.