[sanado]

Hey guys, i just got a quick question to how AAS works. Was just wondering:

Why must atoms be in their ground-state when a sample is to be analyzed?

Ive had a good look across the internet and i still cant find anywhere that gives me a straightforwards answer.

[Alpha-Omega]

AAS iis based on using the ground-state atom population to absorb radiation, as opposed to using the excited-state population to emit radiation.  In AA, the excitation is selective.  Atoms in the ground state optimize sensitivity.

Strange..I just answered this and it seems to have disappeared!!!!!  Glad I kept a copy of the original e-mail notification!!!

[sanado]

So does this mean that an atom in its excited state wont as readily absorb the light that the lamp emits?

[Alpha-Omega]

Per the reference I sent you:

"The light produced by the hollow-cathode lamp is emitted from excited atoms of the same element which is to be determined. Therefore the radiant energy corresponds directly to the wavelength which is absorbable by the atomized sample.

This method provides both sensitivity and selectivity since other elements in the sample will not generally absorb the chosen wavelength and thus, will not interfere with the measurement. To reduce background interference, the wavelength of interest is isolated by a monochromator placed between the sample and the detector."