How is mass-to-charge ratio (m/z) determined?

In mass spectrometry, the mass-to-charge ratio (m/z) tells how heavy an ion is compared to its electric charge.

Here’s how it is found, step by step:

1. Ionization:
   The sample is turned into charged particles (ions).
   • If it loses one electron → charge = +1
   • If it loses two electrons → charge = +2
2. Acceleration:
   The ions are pushed by an electric field so they move fast.
3. Separation:
   The ions pass through a magnetic or electric field.
   • Light ions bend more.
   • Heavy ions bend less.
4. Detection:
   The detector measures where or when each ion arrives.
5. Calculation:
   The mass spectrometer calculates m/z = mass ÷ charge.
   • Example: A 100 Da ion with +1 charge → m/z = 100
   • Same ion with +2 charge → m/z = 50

The instrument then shows a graph (mass spectrum) with peaks for different m/z values.