Mass spectrometry

• The mass spectrometer detects the mass-to-charge ratio m/z of the molecular ion, which gives the molecular mass of the compound.
• The molecular iron peak M+ is the clear peak at the highest m/z value on the right-hand side of the mass spectrum.
• There's also usually a small peak one unit after the M+ peak. This is the M+ 1 peak. This peak exists because 1.1% of carbon is present as the carbon-13 isotope.
• Some molecular ions break down into small pieces known as fragments in a process called fragmentation. This is what causes the other peaks in the mass spectrum. The simplest fragmentation breaks the molecular ion into two species- a positively charged fragment Ion and a radical. Any positive ions formed will be detected by the mass spectrometer but the uncharged radicals are not detected.