Mass spectrometry

  • Atoms that have the same number of protons but different numbers of neutrons are known as isotopes.

  • Isotopes have different atomic masses.

  • The relative abundance of an isotope is the percentage of atoms with a specific atomic mass found in a naturally occurring sample of an element.

  • The average atomic mass of an element is a weighted average calculated by multiplying the relative abundances of the element's isotopes by their atomic masses and then summing the products.

  • The relative abundance of each isotope can be determined using mass spectrometry.

  • A mass spectrometer ionizes atoms and molecules with a high-energy electron beam and then deflects the ions through a magnetic field based on their mass-to-charge ratios m/z

  • The mass spectrum of a sample shows the relative abundances of the ions on the y-axis and their m/z ratios on the x-axis. If z = 1 for all ions, then the x-axis can instead be expressed in units of atomic mass (u).

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