在聚乙二醇(PEG)存在下,钡能与四苯硼钠(NaTPB)生成三元络合物,其中Ba:TPB=1:2。殷学锋等将此反应用于电位滴定钡和间接测定硫酸根,取得良好结果。但要绘制滴定曲线并用离子选择电极确定终点,尚不够简便。鉴于NaTPB是一个很好的示波极谱滴定剂,因此,在一定量PEG存在下,于HAc—NaAc缓冲溶液中,可用TPB直接滴定Ba(Ⅱ),利用TPB的切口(图1)出 In the presence of polyethylene glycol (PEG), barium can form a ternary complex with sodium tetraphenylborate (NaTPB), where Ba: TPB = 1: 2. Yin Xuefeng and other reactions will be used for potentiometric titration barium and indirect determination of sulfate, and achieved good results. But drawing a titration curve and using an ion-selective electrode to determine the end point is not easy enough. In view of NaTPB is a good oscillopolarographic titrant, in the presence of a certain amount of PEG in HAc-NaAc buffer solution can be directly titrated with TPB Ba (Ⅱ), the use of TPB incision (Figure 1) out