Experimental methods in chemical engineering: Atomic absorption spectrometry— <scp>AAS</scp>

Abstract Elements absorb electromagnetic radiation (light) of a specific wavelength in proportion to the number of atoms in its path. As the atoms absorb this light energy, electrons rise from the ground state to an excited state. In atomic absorption spectrometry (AAS), high temperatures produce clouds of atoms from the sample (atomization) and polychromatic radiation passes through it. Monochromators isolate specific emission lines that enter the spectrophotometer. Flames atomize fine sprays produced by nebulizers in flame AAS (FAAS) (2000 K for air/acetylene and 3000 K for /acetylene). In graphite furnace AAS (GF‐AAS), samples are dried then atomize at 1800 to 3000 K. AAS remains a reliable, affordable, and robust technique for detecting trace metals, metalloids (e.g., As, Sb) and even non‐metals, such as P and Se, securing its place alongside modern plasma techniques that have multi‐element capability. Advances in electronics and instrumentation have made AAS faster, more precise, and easier to operate. High‐resolution continuous source AAS (HR‐CS AAS) improves accuracy and handles background correction better. Unlike XRF, AAS is a destructive technique to quantify elemental concentration; however, its ability to deliver high sensitivity and selectivity continues to make it indispensable for analytical chemistry. Coupling AAS with pre‐concentration and extraction strategies enhances sensitivity to detect trace metals even in complex matrices. A bibliometric analysis clusters AAS research into categories centred on: (1) waste water, catalysis, and nanoparticles, (2) FAAS and transition metals (Cr, Co, Ni), (3) microbial applications and Cu, Fe, Ag, Zn, and (4) soil, pollution, and metals (Pb, Cd, Hg).