1.
Explain the technique used in Flame-AAS that will prevent loss of sensitivity of analyte through
ionization. (e) (3 marks)
Solution
In flame AAS ( Atomic Absorption Spectroscopy) the sample is ionised by heating by source of
flame and the atoms of the sample gets converted into gaseous ground state which absorbs
energy (light) of a particular wavelength from source of light and the amount of light absorbed
tells about the concentration of the metal in the sample .
A nebulizer is used to spray the gaseous atoms (vapour) of the metal .
The source of light (hollow cathode lamp ) is most specific one and made up of the same metal
which is to be analysed ang highly specific and thus maintain the sensitivity of the technique.