Rapid Determination of Thallium in Urine by GF-AAS

Urine sample was digested with an acid mixture of H2SO4 and HNO3,and thallium ion in sample solution was oxidized to Tl(Ⅲ) with bromine water.Thallium(Ⅲ) in the form of Tl(Cl)-4 in HCl(1+4) solution was adsorbed on foaming polyurethane and separated from the urine matrix,thus preventing the interferences of inorganic salts and achieving an effect of enrichment.Thallium(Ⅲ) was desorbed from the foaming polyurethane in boiling water and determined by GF-AAS without the use of matrix modifier and omitting the ashing procedure in temperature elevation programme.Limit of determination was found to be 0.1 μg·L-1.Results of recovery test were in the range of 91%-97%.