Spectrophotometric determination of tellurium(IV) in environmental and telluride film samples

Abstract

Three simple, rapid, and sensitive spectrophotometric methods for the determination of traces and ultratraces of tellurium(IV) were studied. These methods were based on either the oxidation of 4-bromophenylhydrazine (4-BPH) by tellurium in a basic medium and coupling with N-(1-naphthyl)ethylenediamine dihydrochloride (NEDA) to give a purple-colored product, the oxidation of 3-methyl-2-benzothazoline hydrazone hydrochloride (MBTH) by tellurium in a basic medium and coupling with chromotropic acid (CA) to yield a red-colored species, or the oxidation of 2,3-dimethoxystrychnidin-10-one (2,3-DMSO) by tellurium in an acidic medium to yield an orange-colored derivative. Beer’s law was obeyed in the range 1.0–25 μg/mL (purple-colored product), 0.7–20 μg/mL (red-colored species), and 0.3–15 μg/mL (orange-colored derivative). The reaction conditions and other analytical parameters were investigated to enhance the sensitivity of the proposed methods. The tolerance limit of various ions has been studied. The methods were applied to the analysis of tellurium in water samples (waste, river, lake, and spring), plant materials, soil samples, and telluride thin films. The results obtained were superior to those obtained using the reported method. The performances of the proposed methods were evaluated in terms of ‘t’-test and variance ratio ‘f’-test, which indicate the advances of the proposed methods over reported methods.