Atomic Absorption Spectroscopy: Lab

In atomic absorption measurements, solid samples are dissolved in a suitable solvent to form a clear solution before atomization.

Insoluble samples are digested with hot mineral acids, either on a hot plate or through microwave heating.

Other methods to obtain clear solutions include oxidizing the sample with liquid reagents, combusting it in closed containers, or fusing it with reagents at high temperatures.

Using low-molecular-weight organic solvents improves nebulizer efficiency and absorbance levels, while extraction from aqueous solutions into water-immiscible solvents reduces matrix interferences.

Calibration curves using multiple standard solutions bracketing the analyte concentration are necessary to determine the linear absorbance–concentration relationship within that concentration range.

The standard-addition method, where one sample portion is spiked with a standard solution, is used to identify and minimize matrix interferences.

Typical detection limits in AAS vary depending on the atomization technique: between 1 and 20 ng/mL for flame atomization, and ranging from 2 to 10 pg/mL for electrothermal atomization.