SIMULTANEOUS DERIVATIVE SPECTROPHOTOMETRIC DETERMINATION OF THORIUM AND URANIUM IN A MICELLAR MEDIUM

Derivative photometric methods for trace analysis of Th(IV) and UO2(II ), and their simultaneous determination in mixtures using 5,8-dihydrox y-1,4-naphthoquinone in a micellar medium are reported. Molar absorpti vity and Sandell's sensitivity of 1:2 Th(IV) and 1:1 UO2 (II) complexe s at their lambda(max), 614.5 nm and 637.0 nm are, 1.19 x 10(4) l/mol/ cm and 1/12 x 10(4) l/mol/cm and 1.95 x 10(-2) mug/cm2 and 2.13 x 10(- 2) mug/cm2, respectively. Calibration graph is linear over the range 9 .28 x 10(-2)-18.56 mug/ml of Th(IV) and 9.52 x 10(-2)-19.04 mug/ml of UO2(II). Though presence of Th(IV) and UO2(II) causes interference in each others determination, 9.28 x 10(-1)-9.28 mug/ml Th(IV) and 9.52 x 10(-1)-9.52 mug/ml UO2(II) when present together, can be simultaneous ly determined using derivative spectra.