atomic absorption spectroscopy

The _______________ determines the color of visible light. 

• wavelength
• speed
• amplitude
• light

Which drawing represents the process by which an absorption line is formed?

• A
• B
• C
• D

When talking about energy levels in an atom, what is an "excited state"?

• The highest energy state of an atom.
• Any level higher than the ground state.
• The lowest energy state of an atom.
• When an atom loses an electron

There are 2 types of burners in flame spectroscopy

• Spark burner

• Turbulent burner

• Continuum burner

• Premix burner

Explain why source modulation is employed in AAS.

• to eliminate interference caused by emission of the

  radiated flame from analyte atoms and flame gas

  species.

• to tune the monochromator to a different spectral line for the element of interest so that there is no overlap.

• to distinguish between the component of radiation

  arising from the source and the component of

  radiation arising from the flame background.

Interference: is the presence of substance that changes the signal from the analyte of interest when analytes concentration remain the same. List 3 interferences in AAS.

• Ionization interference

• Spectral interference

• Chemical interference

• Fundamental interference

What is spectral interference?

• any physical process that effects the light intensity at the analytical wavelength

• some ions will be produced in hot flames

• alteration in analyte absorbance caused by chemical processes during atomization

In analysis of Ca using Atomic Emission Spectroscopy, the presence of sulphate ions and phosphate ions prevent the atomization of Ca²⁺ by forming non volatile salts. Name the type of interference described above.

• spectral interference

• chemical interference

• ionization interference

Methods to prevent chemical interferences.

• Add ionization suppressor

• Add protective agents such as EDTA.

• Use a higher flame temperature.

Which of the following are benefits of the AAS process?

• The detection of mercury ions in soil samples.

• The detection of oxygen ions in water samples.

• The detection of lead ions in water samples.

• The detection of nitrogen ions in soil samples.