Graphite furnace atomic absorption spectroscopy (GFAAS) is a type of spectrometry that uses a graphite-coated furnace to vaporize the sample. Briefly, the technique is based on the fact that free atoms will absorb light at frequencies or wavelengths characteristic of the element of interest (hence the name atomic absorption spectrometry). Within certain limits, the amount of light absorbed can be linearly correlated to the concentration of analyte present. Free atoms of most elements can be produced from samples by the application of high temperatures. In GFAAS, samples are deposited in small graphite or pyrolytic carbon coated graphite tube, which can then be heated to vaporize and atomize the analyte.

Compare between drying and ashing steps in the graphite tube