Molekyljonen
Molekyljonen, also known as the molecular ion, is the ion produced from a molecule by removal of one electron, yielding a radical cation with the formula M+•. In mass spectrometry, it represents the intact molecule in its ionized form, and its m/z value corresponds to the molecule’s molecular mass in electron ionization conditions.
In electron ionization (EI), a molecule M is exposed to high-energy electrons, producing M+• and a free
Observation and interpretation
In a mass spectrum, the molecular ion peak, if present, appears at m/z equal to the molecule’s
Not all compounds form a stable molecular ion; some exhibit rapid fragmentation, making M+• weak or unobservable.
Benzene (C6H6) yields M+• at m/z 78; toluene (C7H8) at m/z 92; methane (CH4) at m/z 16.