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How can mass spectrometry identify isotopes and determine their relative abundances?

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Mass spectrometry identifies isotopes and determines their relative abundances by sorting gaseous ions based on their mass-to-charge ratios.12

The process involves several key steps:
* Ionization: A sample is vaporized and converted into a beam of charged ions.13
* Separation: The ion beam passes through a magnetic field or electric field, which deflects the ions. Because isotopes of the same element have nearly identical chemical properties but different masses, they are separated into distinct beams based on these mass differences.23
* Detection: The separated beams are collected, often using a Faraday cup, where the resulting electrical current is measured.3

Because the current is proportional to the number of ions, the relative abundance of each isotope can be determined by comparing the intensities of these beams. Researchers may also use an isotopically enriched "spike" to calibrate measurements and calculate precise concentrations through isotope dilution.234