Mass resolution Several definitions of mass resolution(R) R- capability of a mass spectrometer to differentiate between masses If M=1000 and M=l, then R =1000 △M AM- mass difference between two adjacent peaks that are just resolved M-nominal mass of the first peak or mean mass of two peak Resolution is also defined as the full width at half maximum(FWHm) of a peak 28.0313 HN+ 280187 △M=0.0126 28.0061 M+△M CO+ 27.9949 28.0313+28.0187 R 2220 0.0126 Time M/ amuM/z