A SIMPLE AND RAPID SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF ULTRA TRACE AMOUNTS OF THALLIUM(III)WITH 4-(4'-N,N-DIMETHYLAMINOPHENYL)URAZOLE AS A NEW REAGENT

摘要

A simple and selective spectrophotometric method is proposed for the determination of ultra trace amounts of Tl(III).The reported method is based on the oxidation of 4-(4'-N,N-dimethylaminophenyl)urazole(DAPU)to the corresponding triazolinedione(TAD)by Tl(III)at pH 4.0.The reaction was monitored spectrophotometrically by measuring the increasing color of TAD compound at 514 nm by the fixed-time method.At a given time of 2.0 min at 30 deg C,the working range of calibration was 5.0 x 10~(-8)-2.0 x 10~(-5)M Tl(III)and detection limit of 5.0 x 10~(-8)M was obtained.The influences of pH,reagent concentration,ionic strength and temperature were studied.The effect of diverse ions on the determination of Tl(III)by the proposed method was also investigated.Thallium in real samples was determined by this method,with satisfactory results.