organic chemistry lab

Mass Spectrometry

Mass spectrometry (MS) is an analytical technique that ionizes chemical species and sorts the ions based on their mass-to-charge

ratio. What you observe is a graph of intensity vs mass-over-charges (m/z) values, where is the mass and z is the charge. What we

usually observe is [M+1]+ value where M is your molecular weight. So, a mass spec can give us the molecular weight of an unknown if

we are able to detect the molecular ion. Additonally, there are many other lower molecular weight ions than can be detected, those are

called fragments. Each molecule is characterized by a fragmentation pattern. The fragmenting ion (that is the molecular ion in most

cases) is called parent ion. The resulting lower weight ions are called daughter ions. The largest peak (in term of intensity) is called

base peak, and it might or might not be the molecular ion.