SIMULTANEOUS DETERMINATION OF HYDRIDE FORMING ELEMENTS BY FURNACE ATOMIC NONTHERMAL EXCITATION SPECTROMETRY (FANES)

Different approaches for the simultaneous determination of arsenic, an timony, bismuth, selenium and tellurium by furnace atomic nonthermal e xcitation spectrometry (FANES) are described. In the direct analysis o f microvolumes of solutions, the results could be improved by working with Pd or Ir as chemical modifiers for the stabilization of the analy tes 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), 0.31 6 ng (Se) and 0.016 ng (Te) could be realized. The combination of hydr ide 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 step s, 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 o f 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 m u g 1(-1) Te4+ are obtained. The influence of hydride forming elements on the determination of each of the elements by the technique of vapo ur generation and in situ enrichment is studied. The results are valid ated using standard reference materials.