金-钼酸铵-罗丹明B体系显色反应的研究

Color Reaction of the Gold-Molybdate-Rhodamine B System

研究了在高氯酸和聚乙烯醇(PVA)存在下金与钼酸盐和罗丹明B(RB)的显色反应,其适宜条件为C_(HClO)=0.81mol/L,C_(MoO)^(2-)=1.4×10^(-3)mol/L,C_(RB)=3.3×10^(-5)mol/L及0.08％PVA。λ_(max)=570nm,表观摩尔吸光系数C为2.65×10~5L·mol^(-1)·cm^(-1),服从比耳定律范围0～10μg Au/25ml。缔合物至少稳定2周,摩尔比Au:RB=1:2。考察了39种共存离子的影响,大多数贱金属不干扰。泡沫塑料分离富集金后,用于岩矿及冶金产品中金的测定,结果满意。

A color reaction of gold ( Ⅲ ) with molybdate and rhodamine B (RB) has been studied in the presence of perchloric acid and ployvinyl alcohol (PVA). The optimum conditions for the determination of gold are 0. 81 mol/L of perchloric acid, 1. 4×10^(-3) mol/L of [MoO_4^(2-) 3.3×10^(-5) mol/L of RB and 0. 08% of PVA. The apparent molar absorptivity is 2. 65×10~5 L ·mol^(-1) ·cm^(-1) at 570 nm. Beer's law is obeyed in the range of 0 to 10 μg/25 ml for gold( Ⅲ ). The molar ratio of Au : RB is 1 : 2. The complex is stable for at least 2 weeks. There is little interference from the 36 studied co-existing ions. The separation and preconcentration of gold with polyurethane foamed plastics are used. The method is satisfactorily applied to the determination of gold in actual samples.