EDTA络合滴定法测定锌,普遍认为适用于0.5%以上高含量的测定,而对0.5%以下至0.05%的低品位则较少采用。根据EDTA络合滴定锌是基于锌与EDTA形成稳定的无色络合物(pK=16.5),在溶液pH4—12这一范围都能定量地直接络合滴定的原理,许多人认为以在酸性介质中进行较好(pH在5—6之间),调整酸度的指示剂以甲基橙、甲基红居多,pH没有严格的控制。实践证明,只要能够确定滴定的最佳pH值。选择较灵敏的酸碱指示剂,严格调整控制pH值,则滴定终点转变快,突跃明显,易 The determination of zinc by EDTA complexometric titration is generally considered to be suitable for high levels of 0.5% or more, whereas less than 0.5% for low levels to 0.05% is less used. Titration of zinc according to EDTA complexation is based on the principle that zinc and EDTA form a stable, colorless complex (pK = 16.5), which allows quantitative complexometric titration to be carried out quantitatively in the pH range of 4 to 12. Most people think that in acidic The medium is better (pH between 5-6), adjust the acidity indicator methyl orange, methyl red mostly pH is not strictly controlled. Practice has proved that, as long as the titration can determine the best pH value. Choose a more sensitive acid-base indicator, strictly adjust the control pH, the titration end-point transition fast, sudden jump obvious, easy