Maleanilic Acids as Highly Selective Reagents for the Amperometric Determination of Thorium (IV)

Abstract

Thorium has been determined amperometrically at an applied e. m. f. of -1.2V with fifteen maleanilic acids. Out of these o-tolyl, p-tolyl, 1-naphthyl, 2-naphthyland 4-amino maleanilic acid were found promising analyticalreagentsand most effective. Th(IV) in the range 6.60 to 2350.0 mg per 100 ml can be determined with an error of ± 0.2%. The interference of fifty-five ions were studied and only five ions Zn(II), Pb(II), Fe(III), UO₂ (II) and Zr(IV) interfered. which could be masked by the addition of S₂O² ₃ or SCN^?, Cl^? or SO^2- ₄, SCN^? or citrate, citrate or tartrate and P₂O^4- ₇ respectively.