Mass spectrometry

Isotopes and mass spectrometry

Isotopes

Atoms that have the same number of protons but different numbers of neutrons.

Atomic mass

The mass of an atom, which can differ among isotopes.

Relative abundance

The percentage of atoms with a specific atomic mass in a naturally occurring sample of an element.

Average atomic mass

A weighted average of an element's isotopes, calculated using the relative abundances and atomic masses.

Mass spectrometry

A technique used to determine the relative abundance of each isotope by analyzing the mass-to-charge ratios of ions.

Mass spectrometer

An instrument that ionizes atoms and molecules to measure their mass-to-charge ratios.

Mass spectrum

A graphical representation showing relative abundances of ions on the y-axis and their m/z ratios on the x-axis.

m/z ratios

Mass-to-charge ratios used in mass spectrometry to categorize ions.

Atomic mass units (u)

Units used to express the x-axis in mass spectrum when z = 1 for all ions.