Chemistry AS EL CI 6.5
- Created by: A.B.
- Created on: 23-10-13 18:13
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- EL The Mass Spectrometer CI 6.5
- 1. Sample Inlet
- Gases or liquids injected but solids are heated to vaporise them.
- 2. Ionisation Area
- A heated filament produces high energy electrons. These electrons bombard any atoms or molecules in the sample and knock the electrons out.
- Cations are formed.
- A heated filament produces high energy electrons. These electrons bombard any atoms or molecules in the sample and knock the electrons out.
- 3. Acceleration area
- Electric field is used to accelerate any ions so that they all have the same kinetic energy.
- 4. Drift Region
- Vacuum here so ions do not collide with air molecules, which could change the direction of their flight path.
- kinetic energy = mass x velocity
- Heavier ions move through more slowly than light ions.
- kinetic energy = mass x velocity
- Vacuum here so ions do not collide with air molecules, which could change the direction of their flight path.
- 5. Ion Detector
- Light ions reach the detector before heavier ones.
- A computer system converts the information into a mass spectrum.
- The Mass Spectrometer and Isotopes
- The mass spectrometer and molecules
- The ion with the greatest mass corresponds to the molecular mass of the sample compound.
- Called molecular ion.
- Corresponds to the parent isotope minus an electron.
- The most intense peak is called the base peak.
- Many peaks because fragments are formed in the ionisation chamber.
- The molecular ion breaks down into fragments
- The ion with the greatest mass corresponds to the molecular mass of the sample compound.
- 1. Sample Inlet
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