Atomic Absorption Spectroscopy (AAS)

I HATE THIS!

AAS and UV similarity

based on absorption of light at specific wavelengths

AAS and UV difference

AAS deals with elemental atoms while UV deals with molecules

electron orbitals

orbitals have diff energies

the closer the orbital is the the center the lower energy it has

electron excitation

when electron gains energy, it moves from inner to outer shell

how is electron excitation carried out

using light energy

absorption spectroscopy for AAS

• each wavelength corresponds to one element atom

• abs depends on atom conc.

another name for AAS

line spectra as abs wavelength is very sharp

desolvation

complete separation of analyte from solvent

volatilization

conversion of analyte molecules into atoms

desolvation and volatization happens cuz?

extreme heat

sources of error

atoms coexisting with molecules and ions

components of AAS

• sample nebulizer

• heat source/atomizer

• light source

• monochromator

• detector/recorder

sample nebulizer

converts sample into aerosol

heat source/ atomizer

converts analyte molecule into individual atoms

light source

provides energy for electron excitation

monochromator

isolates/detects desired wavelength

detector/recorder

measures the absorbed light intensity

components squence

solution goes through nebulization, turns into aerosol molecules, goes through heating, turns into aerosol atoms, light source is provided for electron excitation, thn monochromator isolates desired wavelength, then detector/recorder measures the light intensity thn finally to the signal processor readout.