Every year, we are listening to the news of ever increasing pollution levels. It creates havoc in different ways, somewhere it is form of smog(Delhi) while in other places it is in form of soil erosion, loud noise, etc. We also get continuous reports of how Pollution Control Department is trying to curb these pollution levels by imposing fines on industries, coming up with new bills to be passed in legislation, etc. On a scientific level,there, lies a method to treat the issues of contamination.

This is Atomic Absorption Spectrometry which is quite a important method nowadays as researchers use it to detect heavy metals in water, soil and air.

AAS Method is basically a technique used for the determination of single elements in the chemical compounds using the absorption of optical radiation(light) by free atoms in the gaseous state.

The principle of the technique involves using atomic absorption spectrum of a sample in order to assess the concentration of specific analyte in it. And moreover, to establish the relation between measured absorbance value and the analyte concentration, it relies on Beer Lambert’s Law.

AAS detects elements from samples through application of characteristic wavelengths of electromagnetic radiation from a light source.

So, basically what happens in this technique?

First of all, a sample to be analyzed is taken and converted to liquid (most commonly used) or gaseous form. The solution is drawn in through a small tube present in the front of the device and taken to nebulizer where the solution is broken up into a fine mist(similar to an aerosol spray). The fine mist is carried to the atomizer, such as flame, by a carrier gas. When the sample reaches the flame, the intense heat evaporates the sample and leaves a fine dry residue which are the atoms in the ground state. These ground state atoms are excited with the electromagnetic radiation of specific wavelength. Once excited, they absorb the radiation given to them. The amount of absorbance value is measured and it indicates the absorbance for a particular element.

The electromagnetic radiation comes from a hollow cathode lamp which has argon or neon gas inside. And the flame is typically Acetylene gas or Nitrous oxide gas.

Atomization using flame are also called as FAAS (Flame Atomic Absorption Spectrometry)

The AAS method is extremely used in detection of heavy metals, for analyzing soil and plants for mineral necessary for growth. It is also applied , in forensic for substance identification, in food industry, for quality assurance and testing for contamination, in pharmaceutical, for detecting impurities in drugs.

So, this method is quite useful and will be in the near future. When our environment has become hazardous, methods like AAS become important all the more. It is also necessary to come up with new scientific methods to combat the harm on our nature.