Spectrophotometric determination of trace amounts of tellurium based on its catalytic effect in the reduction of gallocyanine with sodium sulphide

Abstract

A simple and sensitive kinetic spectrophotometric method for the determination of ultra trace amounts of tellurium(IV) has been proposed. It is based on the catalytic effect of Te(IV) on the reduction of gallocyanine by sodium sulphide. The reaction is monitored spectrophotometrically by measuring the decrease in

absorbance of the reaction mixture at 618 nm. The method allows the determination of tellurium concentration in the range 2.0-200 ng/ml, with the detection limit of 1 ng/ml. The relative standard deviation for ten replicate determinations of 20.0 and 50.0 ng/ml Te( IV) is 1.7% and 1.1 %, respectively. The method has been applied to determination of tellurium in water samples.