STUDY OF INTERFERENCES IN GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY BY MEANS OF EXPERIMENTAL-DESIGN

In order to quantify and to investigate the interferences that affect many graphite furnace atomic absorption spectrometric (GFAAS) determin ations, a new approach based on the concepts of experimental design an d empirical modeling is proposed. The results of a study about the int erfering effects by sodium, potassium, calcium and magnesium on the GF AAS determination of tellurium are presented and discussed. In absence of a chemical modifier, two peaks are obtained: the first one was fou nd to be independent of the concentrations of the concomitant elements , while the second one is due to the presence of the interfering eleme nts, according to the following additive linear model: Q(A) = 0.107 0.010 (Na) - 0.006 (K) - 0.019 (Ca) - 0.007 (Mg), where (Na) expressed as coded value means log([Na]/[Te]) and so on, The observed interferi ng effects depend on the presence of carbon and can be eliminated by e mploying a Pd-coated or Ni-coated L'vov platform.