Determination of Iridium by Graphite Furnace Atomic Absorption Spectrometry After Preconcentration with SEPABEADSâSP825 Resin as Sorbent

Abstract

A solid phase extraction and graphite furnace atomic absorption spectrometry (GFAAS) for the determination of iridium with SEPABEADS^âSP825 resin as sorbent was studied. Iridium are preconcentrated on a nonpolar resin SEPABEADS^âSP825 in the form of (L₂·H₃O⁺)₂IrCl₆ ^2- ion-pairs,where L = diphenyl sulfoxide and water was used as eluent. The effects of various parameters such as acidity, flow rate of sample and eluent, type of eluent, amount of adsorbent and interfering ions have been studied. The iridium in 100 mL solution can be concentrated to 1 mL, representing an enrichment factor of 100 was achieved. The detection limit and quantification limit of the method were found to be 0.03 μg L^-1 and 0.1 μg L^-1, respectively. The analytical results for the certified reference samples (GBW07290 and GBW07291) were in a good agreement with the certified value. The relative standard deviation for ten replicate measurements of 0.40 μg L^-1 iridium was 4.1 %. The method was applied to the determination of trace amount iridium in ore samples with good result.