稀土-镍-茜素络合剂异核络合物极谱吸附波的机制

STUDY OF THE MECHANISM ON THE POLAROGRAPHIC ADSORPTIVE WAVE OF THE ISONUCLEAR COMPLEX OF RARE EARTH-NICKEL-ALIZARIN COMPLEXON

在pH4.6的醋酸—醋酸钠溶液中,对稀土—镍—茜素络合剂体系络合吸附波机理的研究证实:异核络合物的组成为RE(Ⅲ):Ni(Ⅱ):ALC=1:1:2;异核络合物为平面结构。采用吸附伏安法,稀土的最低检出量可达2.0×10^(-9)mol/L。

In 0.2 mol/L HAc-NaAc supporting electrolyte, at pH 4.6, a sensitive adsorptive complex wave of isonuclear complex of RE^(3+),Ni^(2+) and alizarin complexon (ALC) is obtained by means of single-sweep polarograph. The composition of the isonuclear complex is detected as La^(3+): Ni^(2+):ALC=1:1:2 by using of photometry and the analysis of the complex precipitate.On the mercury electrode, the adsorptive intensity can be arranged as: RENi(ALC)_2, R_E2(ALC)_2>NiALC>ALC. The occupied area of each isonuclear complexion on the surface of mercury electrode is determined. The determined results are 220—240(?)~2, which it is commensurate with occupied area of two ALCions. The constitution of isonuclear complex on the surface of mercury electrode may well be a plane structure. The isonuclear complex is proved up to decompose into REALC' and Ni-ALC' as soon as by using the cyclic voltammetry.Based on the intensive adsorption of isonuclear complex, the limits of detection are down to 2.0×10^(-9) mol/L for Gd, Er, Tm, Yb and to 4.0×10^(-9) mol/L for the other rare earth ions by means of adsorptive voltammetry.