Spectrophotometric determination of trace amounts of tellurium(IV) with tetramethylthiourea

Abstract

A spectrophotometric method for the determination of trace amounts of tellurium(IV) in dilute hydrochloric acid is described. Concentrations of between 0.2 and 7 µg ml^–1 of tellurium(IV) in the final solution can be determined by measuring the absorbance at 382 nm of the complex formed by the reaction of tellurium(IV) with tetramethylthiourea (ε= 2.14 × 10⁴ l mol^–1 cm^–1). The method is simple, reliable and sensitive. Those foreign ions that interfere in the determination of tellurium(IV) are bismuth(III), selenium(IV), iron(III) and copper(II).