Ag(Ⅰ)沉淀-Ni(Ⅱ)置换-EDTA滴定法测定可溶性氯化物中氯含量研究

Study on Accurate Method of Determining Chloride Content in Easy Dissolving Chloride by Ag(Ⅰ)PrecipitationNi(Ⅱ) Displacement-EDTA Titration

研究了采用Ag(Ⅰ)沉淀-Ni(Ⅱ)置换-EDTA滴定法准确测定可溶性氯化物中含氯量的方法。试样溶解后,先用AgNO3沉淀Cl-,沉淀经过滤,加入过量Ni(CN)42-发生置换反应,然后在pH为9.0￣10.0的氨性缓冲溶液中,以紫脲酸铵为指示剂,用ED TA标准溶液滴定置换出的Ni2+。测定结果的RSD<0.1%,加标回收率R=99.1%～101.2%。改进后的本法,终点现象明显、准确度高、干扰小。

The study deals with accurate method of determining chloride content in easy dissolving chloride by Ag（Ⅰ）precipitation-Ni（Ⅱ）displacement-EDTA titration. After sample is dissolved, the Cl^- is deposited by using solution of AgNO3. After this sediment is filter and excessive Ni（CN）4^2- is added, and thus, the displacement reaction have taken place. In the ammoniacal buffer solution that pH is 9.0～10.0, with murexide as the indicator and EDTA as the standard solution, displacement Ni^2＋ is titrated to end point. RSD 〈 0.1%, and R is between 99.1% and 101.2%. The improved method is effective of end point, the degree of accuracy is high and with little disturbance.