Highly sensitive spectrophotometric determination of trace amounts of tellurium(IV) with the tungstate–basic dyes–poly(vinyl alcohol) system
Three highly sensitive spectrophotometric methods have been developed for the determination of tellurium(IV), based on its colour reactions with tungstate and basic dyes (BD) in aqueous solution in the presence of poly(vinyl alcohol).Tellurium(IV) reacts with tungstate and BD to form ion-association complexes. The molar absorptivities are between 1.76 × 107 and 3.33 × 107 dm3 mol–1 cm–1, the highest value being found with Nile blue. Suitable conditions for the reactions and the effects of foreign ions were investigated. The methods have been successfully applied to the spectrophotometric determination of trace amounts of tellurium(IV) in smoke ash samples.