Atomic Absorption Spectrometry (AAS)
Description of method
Atomic absorption spectrometry is the measurement of an absorption of optical radiation by atoms in the gaseous state.
In atomic absorption, the radiation of an element-specific spectral light source is passed through the sample dissociated into atoms, and the attenuation of the radiation caused by the absorbing atoms is measured. The decisive feature is that the radiation of the light source is modulated at a particular frequency and the amplifier connected behind the receiver is tuned to the same modulation frequency. AAS is thus in a position to unambiguously differentiate between the element-specific radiation of the element of interest and unspecific radiation from the sample matrix. The methods most widely used, flame and graphite furnace technique, are applied at ZEA-3.
Features of AAS
- The method is particularly suited for single-element determinations, but also to a certain extent for multi-element analysis.
- The measuring time for aqueous solutions (without calibration, evaluation and sample preparation) is about 10 seconds (flame) and 10 minutes (graphite furnace) per sample and element.
- The determination limits in aqueous solutions range from 5 µg/ml (Ti) to 0.5 ng/ml (Cd; Ag) depending on the element. In most cases, they are in the range of 10 ng/ml.
Sample-oriented digestion methods such as microwave, fusion, and acid digestion are employed.
Examples of materials
Wipe samples / seawater / groundwater / urine