STUDIES ON ELECTROANALYTICAL CHEMISTRY OF RARE EARTH ELEMENTS X. SINGLE-SWEEP POLAROGRAPHIC INVESTIGATION OP ADSORPTIVE COMPLEX WAVE OP GADOLINIUM-ALIZARIN RED S

In a supporting electrolyte containing 2×10~(-4)M Alizarin Red S, 0.1 M NH_3-NH_4Cl and at pH 9.6, we obtained an adsorptive complex wave of gadolinium-Alizarin Red S by single-sweep polarography. The peak potential of the derivative wave is -0.69V (S.C.E.). The limit of detection for gadolinium is 6×10~(-8)M.We have determined the composition of the complex which is 1:3 Gd-Alizarin Red S and confirmed that the wave is an adsorptive complex wave. The electrode processes may be presented as follows:??The total electrochemical reaction is??