SPECTROPHOTOMETRIC DETERMINATION OF TELLURIUM BY EXTRACTION OF ITS 1-PYRROLIDINECARBODITHIOATE WITH MOLTEN NAPHTHALENE

A new reliable method for the spectrophotometric determination of tellurium(IV) after extraction of its 1-pyrrolidinecarbodithioate into molten naphthalene is developed. Tellurium reacts with 1-pyrrolidinecarbodithioate to form a water-insoluble, thermally stable colored complex which can be quantitatively extracted into molten naphthalene in the pH range of 0.5-2.5. The extracted naphthalene crystals are dissolved in dimethylformamide. The absorbance of the solution is measured at 445 nm. Based on the thermal instability of selenium complex of this reagent, a method is suggested for the simultaneous determination of tellurium and selenium using this technique and the liquid-liquid extraction at room temperature.