AAS (Atomic Absorption Spectroscopy)

AAS (Atomic Absorption Spectroscopy) is an elemental analysis technique that measures the concentration of specific metal elements by detecting the amount of light absorbed by free ground-state atoms in a vapour phase. The fundamental principle is based on the Beer-Lambert law: atoms of a given element absorb light at characteristic wavelengths specific to their electronic transitions. A hollow cathode lamp — a separate lamp for each element — emits a narrow emission line at precisely the wavelength absorbed by the target element. The more atoms present in the light path, the greater the absorption, allowing quantitative determination of element concentration.

AAS is a well-established, single-element technique used for the determination of heavy metals in food, water, and environmental samples. While multi-element techniques like ICP-OES have largely supplanted AAS for high-throughput laboratory analysis, AAS remains valuable for dedicated single-element determination where its robustness, lower instrument cost, and well-validated methods offer practical advantages. At Ovalab’s laboratory, AAS techniques are applied for targeted heavy metal determinations in specific matrices where validated AAS methods are referenced by regulatory standards.

Two major AAS configurations are used in food analysis: Flame AAS (FAAS), where the sample solution is aspirated into an air-acetylene or nitrous oxide-acetylene flame (2,100–2,700°C) — providing fast analysis (10–20 samples/hour) with detection limits in the mg/L range; and Graphite Furnace AAS (GFAAS/ETAAS), where a small volume of sample (5–50 µL) is injected into a graphite tube heated in programmed stages to atomize the sample — achieving detection limits 100–1000x lower than FAAS (µg/L to ng/L range) for elements like lead, cadmium, and arsenic.