Interpreting fragmentation patterns in a mass spectrum.

https://www.youtube.com/watch?v=T34mkIRwQgg

What happens in mass spectrometer

Beam of electrons fired at the sample, causes the sample to lose an electron ,forming a positive ion

This is called the molecular ion (this moves down mass spectrometer, gives spectrum like this)

What does m/z ratio tell us

The ratio between mass and charge of molecular ion

There is one prominent peak on far right of spectrum called M+ peak, tells us relative mass of molecule.

Pentane has molecular mass of 72 , this is shown by molecular ion peak

What happens during fragmentation

A bond breaks, and we form an ion + radical.

Only ion detected by mass spectromter, in this case it would b the butyl ion

How is m/z ratio worked out

by adding the relative atomic masses of atoms in fragments.

Identify fragments forming the peaks shown for propan-1-ol

Forms the molecular ion peak with an m/z ratio of 60