AASinstrument

AAS instrument, short for atomic absorption spectrometry instrument, is an analytical device used to determine the concentration of elements by measuring the absorption of light by free atoms in the gaseous state. Each element has characteristic wavelengths at which it absorbs light, enabling selective quantification when a sample is atomized and illuminated.

A typical AAS setup includes a light source, an atomization system, a wavelength-selective monochromator, and a detector with associated electronics. The light source is usually a hollow-cathode lamp specific to the element of interest, though sometimes a continuum source is used. The atomizer converts the sample into free atoms, most commonly a flame or a graphite furnace. The monochromator isolates the element’s absorption line, and the detector records the transmitted light, which is related to concentration by Beer-Lambert law. The instrument is calibrated with standards, and often employs an internal standard or the method of standard additions to cope with matrix effects.

Variants of AAS include flame atomic absorption spectroscopy (FAAS), graphite furnace atomic absorption spectroscopy (GFAAS or ETAAS), hydride-generation AAS (HG-AAS) for elements like arsenic and antimony, and cold-vapor AAS (CVAAS) for mercury. Each mode offers different sensitivity and sample throughput, with graphite furnace providing higher sensitivity for trace analyses and flame methods offering simplicity and speed.

Common applications span environmental analysis (water and soil contaminants), clinical chemistry (trace metals in biological samples), food and beverage testing (pigments, minerals), and geology/mining. Interferences can arise from spectral overlap and matrix effects, requiring careful calibration, background correction, and sometimes alternative sample preparation.

Overall, AAS instruments are valued for their robustness, relatively low cost, and suitability for routine, element-specific quantification across diverse fields.