Mass Spectrometry (MS)

Mass Spectrometry (MS)

1. Bombarded molecules with high energy particles

   • Usually electrons
   • Molecule converted into charger ions
   • Causes bonds to break as they have shared electrons, they create ions
     • Which is an atom which has lost an electron
       • Left with positively charged ion.

2. Positively charged ions include:

   • Molecular ion
     • Parent molecule minus an electron
   • Fragment ions
     • Charged fragments of original molecule.
   • Broken bonds loose electrons from fragment

3. Provides a signature for that drug we are creating.

4. When bonds are broken, it breaks into two fragments

   • As each bond that could be broken only gets broken at one point for each interaction
   • Different size fragments will deflect at different amounts of light.

5. Measure mass to change ratio

6. Magnetic filed and detect and direct those charged fragments onto the detector

7. Positive ions

   • Separated by deflection in electromagnetic field
     • Controlled by power of electromagnets
   • Deflection according to mass/ charged ratio (m/z)
   • Typically single (ie +1) charge
   • Greater deflection with lower mass

8. Mass detector

   • Magnetic filed altered
   • Directs ions onto detector.
   • Response related to ion abundance
     • Spectra: Mass/ charge ratio (m/Z) on X axis
     • Response on Y axis

9. Fragments

   • Have different masses
     • Different atoms
   • Different M/Z ratio

10. Identification

    • Some fragments more likely to occur
    • Combinations of fragments
      • Computers can identify present molecule
    • Identify original molecule

11. Mass Spectrum- furthest to right is 'parent molecule' no bonds broken

    • Analyse unknown compound with mass Spectrometry method
    • To determine what it is. Cn also do it mathematically.

12. Parent compound

    • Bombarded with high energy particles
      • usually electrons
    • Breaks up molecule
      • Smaller daughter fragments
      • Fragment masses build structure of original molecule

13. Mass of fragment

    • RAM of atoms

14. Fragmentation

    • Molecular ion
      • 1 electron lost from
      • Almost identical mass to parent RMM
    • Parent molecule
      • Fragments in various places
      • Indicate shape of parent molecule

15. No tables of data for comparison

16. Peaks in spectra

    • Fragments of original molecule
    • m/z relates to mass of fragment

17. Fragment determination

    • Computers commonly used
      • Manual verification is essesntail
    • RAM of elements
    • Combination of atoms