Abstract：The composition of superalloy is complicated, so the determination of trace tellurium by graphite furnace atomic absorption spectrometry(GF-AAS) is seriously affected by matrix and alloying elements. The interference elements should be separated firstly by extraction. The diantipyrylmethane (DAM)-hydroiodic acid (HI) three-phase system has high selectivity to the extraction of tellurium. The third liquid phase formed in this system is the dispersion phase of DAM-HI associated complex in mixed solvent of trichloromethane and benzene. The extraction conditions of DAM-HI three-phase system were optimized in this study. The results showed that the distribution ratio of tellurium in the third liquid phase, the second phase and water phase was 8 400∶1 600∶1. The enrichment factor of tellurium in the third liquid phase of this extraction system was up to 21. Meanwhile, the matrix and alloying elements in superalloy could be effectively separated, eliminating the interference of these elements with the determination of tellurium by graphite furnace atomic absorption spectrometry. The third liquid phase was directly injected after dilution. The palladium nitrate was used as modifier. Moreover, the temperature procedure of graphite furnace was optimized. The background interference problem caused by organic matters was solved, and the stable absorbance of tellurium could be obtained. Consequently, a new determination method of trace tellurium in high temperature alloy by graphite furnace atomic absorption spectrometry (GF-AAS) after enrichment with the third liquid phase (DAM-HI) was established. The detection limit of method was 0.055 μg/g. The proposed method was applied to the determination of trace tellurium (0.50-83 μg/g) in certified reference material of superalloy. The found results were consistent with the certified values. The relative standard deviation (RSD, n=8) was less than 20%.
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