Illustrated Glossary of Organic Chemistry - Mass spectrum

Illustrated Glossary of Organic Chemistry

Mass spectrum: A plot of ion relative abundance (on the y-axis) versus m/z (on the x-axis).

Mass Spectrum of Methane (CH₄)


	m/z

m/z	Relative abundance (%)	Assignment
18	< 0.5	M+2	Molecular ion
17	1.1	M+1	Molecular ion
16	100.0	M	Molecular ion; base peak
15	85.0	M - H	Fragment
14	9.2	M - 2H	Fragment
13	3.0	M - 3H	Fragment
12	1.0	M - 4H	Fragment

Related terms: Mass spectrometer, mass spectrometry, electron impact ionization, EI, chemical ionization, CI, MALDI, gas chromatography-mass spectrometry, GC-MS, exact mass, nominal mass, high-resolution mass spectrometry
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