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Chemistry · Glossary

What is Mass spectrometry?

Also known as: mass-to-charge ratio · mass spectrum · base peak

Definition 32.1 University Chemistry — Year 2 · Chapter 32 — Mass Spectrometry and Atomic Spectroscopy

Mass spectrometry turns the molecules of a sample into gaseous ions, separates the ions according to their mass-to-charge ratio m/zm/z (the mass in unified atomic mass units divided by the number of charges) and counts them. The mass spectrum plots the abundance of the ions against m/zm/z, usually as relative intensities; its most intense peak, set to 100, is the base peak.

A time-of-flight analyser (schematic). Ions accelerated through the same potential difference U leave with the same kinetic energy; in the drift tube the lighter ones travel faster and reach the detector first.
A time-of-flight analyser (schematic). Ions accelerated through the same potential difference UU leave with the same kinetic energy; in the drift tube the lighter ones travel faster and reach the detector first.
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