Selective and sensitive liquid-liquid extraction and spectrophotometric determination of tellurium(IV) using sulfur containing reagent

Abstract A simple strategy is developed for the extractive spectrophotometric determination of tellurium(IV) by using sulfur containing reagent, 4-(4'-chlorobenzylideneimino)-3-methyl-5-mercapto-1, 2, 4-triazole (CBIMMT). The [tellurium(IV)-CBIMMT] complex quantitatively extracted in dichloromethane from 3 mol L −1 of hydrobromic acid medium. The 1:2 [tellurium (IV)-CBIMMT] orange coloured complex has λ max 423 and 494 nm and stable for more than 48 h. The extracted complex have molar absorptivity 0.6686 × 10 4  L mol −1 cm −1 and 0.4274 × 10 4  L mol −1 cm −1 while Sandell's sensitivity is 0.01908 µg cm −2 and 0.03115 µg cm −2 at 423 nm and 494 nm is respectively. The system adheres to Beer's law upto 20 µg mL −1 at both wavelengths; however Ringbom's plot suggests optimum concentration range is 7.0–12.5 µg mL −1 and 8.0–14.5 µg mL −1 at 423 and 494 nm respectively. The limit of detection of the method is 0.15 µg mL −1 . The method has been applied for analysis of environmental and real samples.