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) determinations, a new approach based on the concepts of experimental design and empirical modeling is proposed. The results of a study about the interfering effects by sodium, potassium, calcium and magnesium on the GFAAS determination of tellurium are presented and discussed. In absence of a chemical modifier, two peaks are obtained: the first one was found to be independent of the concentrations of the concomitant elements, while the second one is due to the presence of the interfering elements, 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 interfering effects depend on the presence of carbon and can be eliminated by employing a Pd-coated or Ni-coated L'vov platform.