Chemical Instrumentation

Graphite Furnace Atomic Absorption Spectrometry

  • Graphite Furnace is based on the same principles as Flame Atomic Absorption Spectrometry. 
  • The main difference is in the atomization of the sample.
  • Instead of the Flame, the Graphite Furnace uses an electrothermal atomizer which is a small graphite tube.
  • Graphite Furnace is a more sensitive technique for the determination of metals. Flame AAS can analyse samples in the ppm range but the Graphite Furnace can analyse concentrations in the ppb range.

Graphite Furnace

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Basic Layout of a Graphite Furnace Instrument
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Graphite Tube

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  • The Graphite tube is where the atomization takes place.
  • A few microlitres of sample is injected into the tube.
  • The temperature of the tube increases over a matter of seconds and can reach up to 3000oC depending on the element being analysed.
  • The atomization of the sample takes place in milliseconds.
  • The absorption of the atomic vapor is then measured in the tube immediately above the heated surface.

Uses of Graphite Furnace Atomic Absorption

  • The Graphite Furnace is used for the same tests as the Flame Atomic Absorption Spectrometer. 
  • The Graphite Furnace is more sensitive than the Flame AAS so it can be used for trace metal analysis in the ppb range.
  • For some metals which can cause poisoning in relatively small quantities it is vital to test in the ppb range for their presence in food and water.