钍－茜素氨羧络合剂极谱络合吸附波的研究

摘要

A sensitive adsorptive wave of thorium-Alizarin complexon complex has been obtained by using single-sweep polarography in 3×10-2 mol/L potassium biphthalate -0.1 mol/L acetate mixed buffer (pH 5.0) containing 1.2×10-5 mol/L alizarin complexon. The second-order derivative peak height of the complex at -0.60 V (vs.SCE)is proportional to the concentration of Th (Ⅳ) over the range of 3.0×10-8～3.0×10-6 mol/L. The detection limit for Th (Ⅳ) is 1.5×10-8 mol/L. The molar ratio of each component in the complex has been estimated as nTh(Ⅳ) ∶ nALC=1 ∶ 1. The properties of the polarographic wave and the electrode reaction mechanism are also discussed in detail. The recovery of standard addition of the method for Th (Ⅳ) is 101.5%～103.2% with precision of less than 4% RSD (n=5). The method has been applied to the determination of the trace Th (Ⅳ) in the ore and clay samples with satisfactory results.%在邻苯二甲酸氢钾和醋酸混合底液(pH 5.0)中,钍与茜素氨羧络合剂(ALC)形成电活性络合物，在单扫描极谱仪上于-0.60 V(vs.SCE)产生一灵敏的络合吸附波，其二阶导数峰高与钍的浓度在3.0×10-8～3.0×10-6 mol/L呈线性关系，检出限为1.5×10-8 mol/L。用等摩尔连续变化法测得该络合物的摩尔比为nTh(Ⅳ)∶nALC=1∶1，并探讨了极谱波的性质和电极反应机理。方法用于矿石和粘土中痕量钍的测定，RSD(n=5)<4%, 加标回收试验，回收率为101.5%～103.2%。