Graphite Furnace Atomizer

This atomizer is a non-flame atomizer in which an electrically heated closed graphite tube has transparent end windows. The tube generates a cloud of atoms which is exposed to the light from the hollow cathode lamp. This tube encloses in a circular metal jacket.

 The higher the atom density and longer the residence time in the tube the lower will be the detection limit. Residence time is the time spent by the analyte in the optical path. This time is less than 1 second thus it is more sensitive.

Construction:

It consists of a metal chamber with two separate jackets having water flowing continuously in it. This absorbs the excess heat present in the furnace.

The graphite cylinder is present in the middle of the metallic chamber. A small hole is present in the graphite cylinder for the introduction of the sample.

An inert gas is filled (Ar) is filled inside the chamber.

Working:

The sample is introduced in the graphite chamber by use of a micropipette.

Light from the hollow cathode lamp passes through the window at each end of the furnace.

Inert gas Argon is passing through the graphite furnace which prevents the oxidation of graphite.

Heating

The heating process is divided into further three steps:

Desolvation: In the first step, about 100^oC heat is provided to evaporate the solvent.

Ashing: In the second step, about 800^oC temperature is provided to vaporize the organic compound present in the sample.

Atomization: In the third step, (heating to between 2,000-3,000^oC) atomizes the sample. It occurs over a few milliseconds to seconds.

Advantages and Disadvantages of Graphite Furnace Atomizer

Advantages	Disadvantages
Small quantity of sample	The sample may not completely atomize.
Sensitivity is enhanced.	Professional operators can operate.
No sample preparations are needed.	It is an expensive technique.
Low spectral interference.	High matrix interference.