What are the differences between atomic absorption spectroscopy and flame photometry?

Question

What are the differences between atomic absorption spectroscopy and flame photometry?

Answer 1

flame photometry is a type of atomic EMISSION spectroscopy.  The sample is excited (raised to a high temperature), causing the emission of light.  the wavelength of the emitted light is a function of the energy of the excited electrons, so each element has a characteristic set of wavelengths.  usually a single wavelength is detected and the intensity of the emission is used to calculate concentration.

Atomic adsorption works in the reverse way.  A light of a standard wavelength (a wavelength characteristic of the target element) is passed through a flame containing the unknown substance, and the concentration of the target element is determined by the reduction in the energy of this light as it passes through the flame.  the light is adsorbed by the electrons in the target element, kicking them into a higher orbit or completely out of the atom, depending on the energy involved.

basically, one method involves the emission of the energy as an excited electron kicks back down to a lower state, and the other involves the adsorption of energy as an electron is kicked up an energy state.  Same basic principle-change in electron energy relates to light of a specified wavelength and the change in the amount of that light can be measured and converted to a concentration.  

Answer 2

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