稀土Ⅲ—钼Ⅵ—三溴偶氮氯膦异多核络合物极谱吸附波的研究

Polarographic adsorptive wave of rare earthⅢ-molybdenumⅥ-tribro mo-chlorophosphonazo isopolynuclear complex

在 pH8 7的氨 -氯化铵缓冲溶液中 ,稀土 与钼 、三溴偶氮氯膦形成的异多核络合物于 -0 89V(vs SCE)产生一灵敏的阴极极谱波 ,其二次导数峰高与稀土 浓度在 3 4× 1 0 -8～ 4 0× 1 0 -6mol/L范围内呈线性关系 ,检出限为 2 0×1 0 -8mol/L。研究了异多核络合物的形成及电极反应机理 ,在单扫描极谱上用单纯形法测定了该络合物的组成 ,用此方法测定了稀土球墨铸铁标样中稀土总量 ,结果令人满意。

The adsorptive wave of r are earth*#-molybdenum*&-tribrom o-chlorophosphonazo isopolynuclear complex has been obtained by us ing single-sweep polarography in a mmonia buffer solution at pH8.7.Th e peak potential is -0.89V(vs.SCE) .The peak height is proportional t o the concentration of RE*# over t he range from 3.4×10 -8 to 4.0×10 -6 mol/L.The limit of detection is 2. 0×10 -8 mol/L.The properties of the polarographic waves and the mechanism of electr ode reaction are discuss ed in detail.With single sweep pol arography the composition ratio of the complex is determined to be RE ∶Mo∶TBCPA=1∶1∶4 by simplex method. The method has been applied to the determination of trace RE in nodular cast iron sa mples with satisfactory results.