BRAINCAKEHigh Resolution Mass Spectrometry
In a mass spectrum, the peak with the highest m/z value (ignoring small isotope peaks) is usually the molecular ion peak, M+. Its m/z value gives the relative molecular mass, Mr, of the compound.
A low resolution mass spectrometer measures m/z to the nearest whole number. This is not enough to identify a molecule, because many different molecular formulae share the same whole-number Mr. For example, C3H8, CO2 and C2H4O all have Mr = 44.
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More in Organic Analysis
- Identifying Functional Groups
- Test Tube Tests for Organic Compounds
- Precise Relative Molecular Mass
- Infrared Spectroscopy
- Bond Vibrations and IR Absorption
- The Fingerprint Region
- Interpreting IR Spectra
- Infrared Radiation and the Greenhouse Effect
All 9 lessons in Organic Analysis · All AQA AS-level Chemistry topics