Catalytic Determination of Traces of Tellurium (IV) Using the Reduction of Lauth’s Violet with Sodium Sulfide

A simple, rapid and sensitive method has been developed for determination of traces of tellurium (IV) (7.0-120.0 ng/ml) based on it’s catalytic effect on the reduction reaction of lauth’s violet by sulfide ion at pH 4.2. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of lauth’s viole at 600 nm by the fixed time method. The detection limit is 5.0 ng/ml and the relative standard deviation for 50.0 and 100.0 ng/ml Te (IV) is 2.5 and 1.8 % respectively. The method is free from most interferences and it was applied to determination of tellurium in water real samples.