atomabsorptions

Atom absorption refers to the process by which free atoms absorb electromagnetic radiation at specific wavelengths corresponding to electronic transitions within the atoms. When photons match the energy difference between electronic levels, atoms absorb energy and electrons are promoted to higher levels, producing characteristic absorption lines in a spectrum. The observed absorbance depends on the number of absorbing atoms along the light path, the path length, and the probability of the transition; this relationship is commonly described by the Beer–Lambert law, A = εlc, where ε is the molar absorptivity and l is the path length.

Atomic absorption spectroscopy (AAS) is the analytical technique that exploits this phenomenon to quantify elements in a sample. In AAS, light from a element-specific source passes through a sample containing free atoms in the ground state. The reduction in transmitted light at the element’s characteristic wavelengths is measured and related to concentration. AAS is valued for its specificity and sensitivity, particularly for trace metal analysis.

Common implementations include flame atomic absorption spectroscopy (FAAS), which atomizes the sample in a flame, and graphite furnace atomic absorption spectroscopy (GFAAS), which uses a miniature electrothermal atomizer for higher sensitivity. Other variants include hydride generation AAS for certain elements and background-corrected methods to mitigate spectral and chemical interferences.

Applications of atom absorption span environmental monitoring, clinical analysis, food and drink safety, and industrial testing. Limitations include matrix effects, interferences from other species, and the need for careful calibration and atomization optimization to achieve accurate results. Atomic absorption is frequently contrasted with atomic emission spectroscopy, where elements are quantified by emitted rather than absorbed light.