Atomic Absorption Spectroscopy

The transformation of a liquid into spray of small droplets of aerosols is called ___________.

Select the process occuring during atomization

• desolvation

• nebulization

• combustion

• volatilization

There are 2 types of burners in flame spectroscopy

• Spark burner

• Turbulent burner

• Continuum burner

• Premix burner

Give the type of this AAS.

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.

Radiation source in AAS is a ___________ which provide narrow emission bands

• continuum source

• line source

Common radiation source for line source used in AAS

• Spark or arc ablation

• Hollow cathode lamp (HCL)

• Electrodeless discharge lamp (EDL)

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