Graphite furnace atomic absorption spectrometry (GFAAS) is also known as electrothermal atomic absorption spectrometry (ETAAS). GFAAS is an established technology for quantifying elements at trace and ultra-trace levels (down to low μg/L) while using only small sample volumes (usually less than 100 μL).

In GFAAS, a known amount of sample solution is injected into a graphite- or pyrolytic carbon-coated graphite tube, which can then be heated to vaporize and atomize the analyte. The atoms absorb ultraviolet or visible light of an element specific wavelength and make transitions to higher electronic energy levels. The amount of absorption is a measure for the concentration of the element of interest in the sample solution. Concentrations can be derived after calibrating the instrument with standards of known concentration.