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What does the horizontal axis of a mass spectrum show?

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Figure 1: An electron bombardment ion source in cross section. An electron beam is drawn from the filament and accelerated across the region in which the ions are formed and toward the electron trap. An electric field produced by the repeller forces the ion beam from the source through the exit slit. — mass spectrometry Figure 1: *An electron bombardment ion source in cross section.* An electron beam is drawn from the filament and accelerated across the region in which the ions are formed and toward the electron trap. An electric field produced by the repeller forces the ion beam from the source through the exit slit.

In a mass spectrum, the horizontal axis represents the mass-to-charge ratio, commonly denoted as m/z.12

This axis displays the mass of the ionic fragments relative to their charge. In many cases, particularly when fragments bear a single positive charge (z = 1), the horizontal axis effectively shows the masses of the fragments directly. The vertical axis of the plot represents the intensity or relative abundance of these ionic fragments.12