Polarographic Adsorptive Wave of Scandium-Alizarin Complexan Complex

A sensitive adsorptive wave of scandium-alizarin complexan complex has been obtained by using single _ sweep polarography in 3×10-2 mol/L potassium acid phthalate and 0.15 mol/L formic acid-sodium formate mixed buffer solution(pH 4.8)containing 1.2×10-5 mol/L alizarin complexan. The second _ order derivative peak height of the complex at -0.54 V(vs SCE)is proportional to the concentration of Sc(Ⅲ)over the range of 4.0×10-8～3.0×10-6 mol/L. The detection limit is 2.0×10-8 mol/L. The molar ratio of the components in the complex has been estimated as n(Sc3+)∶n(ALC)=1∶2. The properties of the polarographic wave and the electrode reaction mechanism were also discussed in detail. The method has been applied to the determination of the trace Sc(Ⅲ) in the mineral samples with satisfactory results.