大学化学 >> 2026, Vol. 41 >> Issue (4): 433-437.doi: 10.12461/PKU.DXHX202502067

师生笔谈 上一篇    下一篇

滴定终点误差的来源及其实践意义

邓思怡, 李乐, 陈广慧, 詹顺泽   

  1. 汕头大学化学化工学院, 广东 汕头 515063
  • 收稿日期:2025-02-08 录用日期:2025-04-15 发布日期:2026-04-24
  • 通讯作者: 詹顺泽 E-mail:szzhan@stu.edu.cn Shunze Zhan
  • 基金资助:
    汕头大学高等教育教学研究和改革项目(2004-2005)。

Sources of Titration Endpoint Error and Their Practical Significance

Siyi Deng, Le Li, Guanghui Chen, Shunze Zhan   

  1. College of Chemistry and Chemical Engineering, Shantou University, Shantou 515063, Guangdong Province, China
  • Received:2025-02-08 Accepted:2025-04-15 Published:2026-04-24
  • Contact: Shunze Zhan E-mail:szzhan@stu.edu.cn

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摘要： 终点误差(Et)是分析化学教学的重点内容，教学中通常将指示剂的理论变色点与化学计量点间的差值(EIn)当作终点误差的唯一来源。本文结合实际滴定操作过程，提出终点误差的另一个来源——最后一滴(the last drop)滴定剂引起的终点误差Eld。该误差是正误差，具体数值大小在确定的范围内具有不确定性。进一步系统分析了这种误差对终点误差的影响，重新探讨了滴定突跃、终点误差和指示剂变色点三者间的关系，为科学合理地选择滴定条件、提高滴定结果的准确性提供了更加明确的依据。

关键词: 滴定分析, 终点误差, 最后一滴, 滴定突跃, 误差分析

Abstract: Endpoint error (Et) represents a critical concept in analytical chemistry education. Conventionally, the difference (EIn) between an indicator's theoretical color transition point and the stoichiometric point has been regarded as the exclusive source of endpoint error. This study introduces an additional source of endpoint error—Eld, arising from the last drop of titrant during practical titration operations. This systematic error exhibits positive values with inherent uncertainty within a defined range. We comprehensively analyze the impact of this error on overall endpoint error and re-examine the interrelationships among titration jumps, endpoint error, and indicator transition points. These findings provide enhanced theoretical guidance for optimizing titration conditions and improving measurement accuracy.

Key words: Titration analysis, Endpoint error, The last drop, Titration jump, Error analysis