Suppose the controller on a GFAAS is defective and the furnace is running cold. What effect will this likely have on the number of photons absorbed in the measurements?

Suppose the controller on a GFAAS is defective and the furnace is running cold. What effect will this likely have on the number of photons absorbed in the measurements?

• A. It will decrease the number of photons absorbed
• B. It will increase the number of photons absorbed
• C. It will have little effect
• D. It is not a relevant question because AAS relies on emission of light from electronically excited atoms

Answer: (A)

In graphite furnace atomic absorption spectroscopy, the signal comes from photons that are absorbed by analyte atoms in the ground state as they pass through the atomized sample. If the furnace is running cold, atomization is inefficient, so far fewer atoms are present in the vapor phase to absorb the lamp’s photons. With fewer absorbers in the light path, fewer photons are absorbed, and the absorption signal decreases accordingly. The idea that AAS relies on emission from excited atoms is not correct; emission-based techniques measure light that atoms emit, not the absorption of light by ground-state atoms in AAS.

In graphite furnace atomic absorption spectroscopy, the signal comes from photons that are absorbed by analyte atoms in the ground state as they pass through the atomized sample. If the furnace is running cold, atomization is inefficient, so far fewer atoms are present in the vapor phase to absorb the lamp’s photons. With fewer absorbers in the light path, fewer photons are absorbed, and the absorption signal decreases accordingly. The idea that AAS relies on emission from excited atoms is not correct; emission-based techniques measure light that atoms emit, not the absorption of light by ground-state atoms in AAS.