Atomic absorption spectroscopy is a quantitative analysis technique where atoms in the ground state absorb light of a specific wavelength that is then detected. A light source emitting the desired wavelength is used, and the sample is aspirated into a flame to evaporate the solvent and leave behind neutral ground state atoms. The amount of light absorbed corresponds to the concentration of the element being analyzed. It is commonly used to analyze trace metal elements in samples from industries like healthcare, food, petroleum, pharmaceuticals, and mining.

1. Atomic Absorption Spectroscopy (AAS)
Definition:
Atomic absorption spectroscopy is a type of quantitative analysis where a
specific wave length of light is absorbed by atoms in the ground state
then detected or recorded. The more the number of the atoms, the more is
the intensity of absorption and vice-verse.
Principle:
A special light source (e.g. lamp) of known wavelength is used. A sample
solution is aspirated over a burner into a proper flame aligned with the
light beam. This leads to evaporation of solvent and leave neutral atoms
in ground state. Atoms in the ground state are capable of absorbing light
with energy corresponding to the energy difference between two of their
energy levels. The un-absorbed light is recorded over a detector. This
value can be used to determine the concentration of a given element (or
atoms) within the sample.
This can also be called as metal analysis spectrometer as it mainly used
for metal analysis.
Parts of the AAS:
1) Sample container: This is a beaker like container of sample which
is placed below the burner preferably. A capillary tube drains the
sample to the tip of burner.
2) The burner: Here sample rises to the tip of burner where it is
burned with flame produced by the fuel and oxidant combination.
The sample after evaporation leaves a fine residue of neutral atoms.
3) Fuel and oxidant: This is a very important part of entire process to
be remembered. If the heat produced is not sufficient then the
sample doesn’t form neutral atoms. If the heat of burner is more,
the sample molecules may ionize instead of forming atoms. So
both are undesirable for experimentation. Hence a proper
combination of fuels and oxidant are to be used to produce
recommended temperatures. Commonly used fuels are propane,
Hydrogen and acetylene and oxidants are mostly air or oxygen.

2. 4) Hallow cathode lamp: It is designed to emit light with wavelength
spectrum suitable for a particular element. If the element to be
analyzed is magnesium, the cathode lamp made of magnesium is
used and so for all the other metal elements analyzed like Na, Ca,
K, Zn etc.
5) Amplifier and data recorder.
6) Detector: The used can be a simple photo multiplier tube or photo
cell. The current or potential recorded for the sample absorption is
recorded in computer software and then analyzed.
Applications of atomic absorption spectroscopy:
1) For quantitative analysis of metal elements in any sample.
2) It is especially useful to analyze trace metal elements in plasma and
other body fluids.
3) To determine metal elements in food industry.
4) To estimate Lead in petroleum products.
5) In pharmaceuticals: minute quantities of a catalyst used in the
process (usually a metal) are sometimes present in the final
product and can be determined.
6) In mining: the amount of metals such as gold in rocks can be
determined.