Atomic Fluorescence Spectrometry:

Previously on flame photometry you have learnt about an analytical method based on the emission of radiation through the atomic species which have been excited along with the help of the thermal energy of flame. In this you would learn about other atomic spectrometric methods; therefore, in this method the excitation is caused through an electromagnetic radiation. It is known as atomic fluorescence spectrometry (AFS) as we monitor the fluorescence emission from the excited state.  It is the most presently developed of the primary atomic spectroscopic analytical tools for the determination of concentration levels of various elements in diverse range of samples.

Within AFS, the gaseous atoms acquired through flame or electrothermal atomisation is excited to higher energy levels through absorption of the electromagnetic radiation and the fluorescence emission from these excited atoms is measured. This method incorporates aspects of both emission and absorption.

The major advantage of fluorescence method as compared to absorption measurements is the greater sensitivity achievable since of extremely low background and the interference in the fluorescence signal. AFS is meaningful in studying the electronic structure of atoms and within quantitative elemental analysis. It is used majorly in the analysis of metals within agricultural, biological, industrial and environmental samples.

We start the theory with an understanding of the origin of atomic fluorescence and learn about various mechanisms of the similar. Then we will take up the principle of atomic fluorescence spectrometry that is followed through the instrumental aspects. In the end we will take up a few qualitative and quantitative applications of atomic fluorescence spectrometry. In the further block you would learn about atomic absorption and atomic emission spectrometric techniques and their applications within diverse areas.

Objectives

After studying this unit, you will be able to:

• Elaborates the origin of atomic fluorescence and its different mechanisms,
• Elaborates the principle of atomic fluorescence spectrometry,
• Describe a schematic diagram illustrating different elements of an atomic fluorescence spectrometer,
• Define the factors affecting atomic fluorescence spectrometric determinations,
• Enlist the applications of atomic fluorescence spectrometry, and
• State the merits and limitations of the atomic fluorimetric technique.