Atomic absorption spectroscopy (AAS) is a spectroanalytical technique for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms.

In analytical chemistry the technique is used for determining the concentration of a particular element in a sample to be analysed. AAS can be used to determine over 70 different elements in solution or directly in solid samples.

Set up on an AAS instrument (fig 1)

 

 

 

 

In this technique, the sample is introduced to the instrument and atomised in either an acetylene flame or a graphite furnace. The absorption of light at a specified wavelength, which is characteristic of the element being quantified, is measured and is directly proportional to the concentration of the element in the sample.

 

Quantification (fig 2)

 

 

 

 

 

 

 

Atomic absorption is one of a number of techniques that can be used for the quantification of elements. The technique of choice will depend on analyte concentration, sample matrix, sample throughput and budget.

Compairson of atomic spectroscopy techniques (fig 3)