Simultaneous determination of hydride forming elements by furnace atomic nonthermal excitation spectrometry (FANES)

Different approaches for the simultaneous determination of arsenic, antimony, bismuth, selenium and tellurium by furnace atomic nonthermal excitation spectrometry (FANES) are described. In the direct analysis of microvolumes of solutions, the results could be improved by working with Pd or Ir as chemical modifiers for the stabilization of the analytes during the thermal pre-treatment. Using Ir as a modifier, absolute detection limits of 0.116 ng (As), 0.062 ng (Bi), 0.044 ng (Sb), 0.316 ng (Se) and 0.016 ng (Te) could be realized. The combination of hydride generation and in situ enrichment of the analytes onto a permanent Ir-treated inner surface of the graphite tube of the FANES source has been used as pre-concentration technique. The conditions for all steps, hydride generation, pre-reduction, in situ enrichment, atomization and excitation have been studied. Using compromise conditions for the simultaneous determination of all the elements using a sample volume of 20 ml, relative detection limits of 0.032 mu g 1(-1) As3+, 0.015 mu g 1(-1) Bi3+, 0.012 mu g 1(-1) Sb3+, 0.047 mu g 1(-1) Se4+ and 0.009 mu g 1(-1) Te4+ are obtained. The influence of hydride forming elements on the determination of each of the elements by the technique of vapour generation and in situ enrichment is studied. The results are validated using standard reference materials.