Graphite Furnace Atomic Absorption Spectrometry

Abstract

AbstractGraphite furnace atomic absorption spectrometry (GFAAS) is also known as electrothermal atomization atomic absorption spectrometry (ETAAS). It is an atomic spectroscopic technique in which a small sample is placed inside a graphite tube that is then resistively heated to accomplish sample desolvation (for liquid samples), ashing or charring (to decompose the sample and volatilize some of the matrix), and finally atomization. Typically, the light from a line source characteristic of the element being determined is passed longitudinally through the tube and the absorbance resulting from the presence of free analyte atoms in the gas phase is measured. A continuum source and high‐resolution spectrometer can accomplish a similar objective. The absorbance signal is transient in character, lasting approximately 1–5 s, and the area under this transient peak is generally used in the construction of a calibration curve. Modern instrumentation provides high levels of automation with capabilities of background correction as well as routine methods of sample analysis, for example quality assurance/quality control (QA/QC), standard additions, matrix modification, etc. Since the technique was first introduced in 1969, a lot of progress has been made in understanding the processes occurring within the graphite tube atomizer that ultimately produces the absorbance signal. An understanding of the free atoms formation process has facilitated the application of the technique to the analysis of a variety of complex samples.Graphite furnace (also known as an electrothermal atomizer or ETA) atomic absorption is generally considered an ultratrace and microtrace analytical technique with limits of detection (LODs) in the low picogram range, precision of a few percent (relative standard deviation), and a dynamic range of about three orders of magnitude. In addition to its excellent sensitivity, it is unique in its ability to handle microsamples including aqueous solutions, viscous liquids, slurries, and even solids. In general, there is considerable literature detailing methods and procedures for the determination of a variety of analytes in complex matrices that can be used by the analyst to apply the approach to new, complex analytical needs. When used correctly, this analytical tool can provide precise, accurate analysis for a wide range of sample types.