Standard Article

Modifiers in Graphite Furnace Atomic Absorption Spectrometry—Mechanisms and Applications

Atomic Spectroscopy

  1. Ewa Bulska

Published Online: 15 DEC 2009

DOI: 10.1002/9780470027318.a9125

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Bulska, E. 2009. Modifiers in Graphite Furnace Atomic Absorption Spectrometry—Mechanisms and Applications. Encyclopedia of Analytical Chemistry. .

Author Information

  1. University of Warsaw, Faculty of Chemistry, Warsaw, Poland

Publication History

  1. Published Online: 15 DEC 2009

Abstract

The graphite atomizer is a commonly used reactor where the sample undergoes various processes, leading to the formation of free atoms of the analyte of interest in gaseous phase. Thus atomic absorption of the cloud of atoms could be measured. This process is called atomization and depends strongly on the composition of the sample introduced into the atomizer. In graphite furnace, the sample is gradually heated according to the previously set time/temperature program so that various components of the sample could evaporate. The best conditions for atomic absorption measurements could be achieved when the matrix components evaporate before analyte atoms appear in the gaseous phase. The better the separation of the evaporation of matrix from the evaporation of analyte, less interference occurs during the measurement. It is clear that the efficiency of the separation depends on the volatilities of both matrix and analyte compounds. Generally speaking, the main aim of the modifiers is to provoke intended chemical reaction in order to enhance the separation of matrix and analyte, thus ensuring that the atomization process is free from interferences. Commonly, an excess of reagent—modifier—is added intentionally to the sample or atomizer. Its aim is to transfer the analyte into the less-volatile compounds and/or to transfer the matrix compounds to more-volatile compounds. Moreover, properly designed modification could also play its role in the interaction of the sample with graphite surface and/or unify the atomization process of analyte being present in various species.

Keywords:

  • modifiers;
  • graphite furnace;
  • atomic absorption spectrometry