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

Basic Layout of a Graphite Furnace Instrument

Graphite Tube

  • 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.