Spectrophotometric Investigation and Determination of Scandium Using Semi-Xylenol Orange

The composition, stability constant and molar absorption coefficient of the chelate of scandium ion with Semi-Xylenol Orange (SXO) are determined speotrophotometrically in a medium of chloroacetate buffer. In the scandium-Semi-Xylenol Orange system, Sc(SXO) chelate is formed with a logarithmic stability constant of 19.66 and molar absorptivity of 2.4x10 4 (530 nm) 1 mole −1 cm −1 . The precision and accuracy attainable in a direct photometric microtitration of Sc +++ ion with a 0.001M solution of EDTA using SXO as a metallochromic indicator has been studied. Interferences of different anions and cations on scandium determination are also investigated. Spectrophotometric determination of scandium(III) using SXO at the optimum conditions has been carried out. Beer's law is obeyed for 0-13.49 μg scandium/25 ml.