Mass Spectrometry (Different Analysers) Flashcards
Learn HR-MS, Quadrupole-MS, ToF-MS, RToF-MS, ToF Pros/Cons
Mass Analysers (HR-MS)
High resolution mass spectrometer. Double/Triple focusing with additional sectors and enables the accurate measurement of masses and allows determination of molecular formulae
Mass Analysers (Quadrupoles)
Ions of different mass sequentially scanned through analyser (filter) by varying RF potentials of rods
Mass Analysers (ToF-MS)
All ions accelerated to same energy, high velocities for lighter ions. Pulse of ions pass through drift tube where light ions traverse more rapidly.
Flight time is recorded
Mass Analysers (RToF-MS)
Reflectron uses rings/grids to act as a mirror. Mirror compensates for the spread in KE of ions as they enter the drift tube.
Improves resolution of instrument.
Mass Analysers (ToF Advantages)
- Multiplex Advantage (all ion masses recorded per pulse)
- Mechanically Simple
- Easily miniaturised
- Pulsed operation (suits pulsed sources such as lasers)
Disadvantage:
- Needs ion storage/traps to hold ions