Question

Why would atomic absorption spectroscopy be less sensitive to low source temperature, assuming efficient atomization?

Answer 1

In atomic absorption spectroscopy ,the analyte is converted to free gaseous atoms or atomized using thermal energy/heat .The atoms absorb surplus energy and the valence electron is excited to higher energy levels which is measured as the absorbance of the analyte atoms.

Higher the temperature ,higher is the atomization given by Boltzmann's distribution-

N1/NoE1/KT where E1 =energy difference between excited energy level (to which electron is excited) and ground energy level=energy absorbed by the atom

k=boltzmann's constant

T=temperature

N1=number of atoms excited

No=number of atoms in ground state

The fraction of atom in excited state (population) rises sharply by even 10K increase in temperature

So either flame atomization or electrothermal atomization method is implemented to get the desired temperature range for converting the solid/liquid analyte to volatilize the analyte ,and convert it into ionic species,molecules or free atoms.

Also ,absorbance is proportional to

It is less sensitive to low temperature source hence.