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目的 :配位滴定是一种准确度高的分析方法 ,但仅适用于常量分析。其准确度与滴定剂与金属离子的条件稳定常数和金属离子的浓度有关。分析家们致力于提高该方法的灵敏度和准确度。方法 :本文提出一种非线性回归间接极谱分析法。实验时测定滴定过程中滴定剂的体积和相应的极谱峰高。用非线性回归法处理数据 ,可以求出终点处络合剂消耗的体积和被测物的浓度。本方法灵敏度高且不需要金属指示剂。结果 :通过测定 5×10 -5mol/L的钙离子 ,本文探讨了实验点和回归参数的选择。由于与EDTA络合的金属离子对测定有干扰 ,所以必须进行隐蔽和分离。本方法的准确度令人满意 ,平行测定三次的相对标准偏差不大于 2 % ,回收率约为10 1 2 %～ 10 5 4%
Objective: Coordination titration is a highly accurate method of analysis, but only for constant analysis. Its accuracy is related to the stability constants of titrant and metal ions and the concentration of metal ions. Analysts are committed to increasing the sensitivity and accuracy of the method. Methods: This paper presents a non-linear regression indirect polarographic method. The volume of titrant and the corresponding peak height of the titrant during titration are determined experimentally. Using non-linear regression to process the data, the volume consumed by the complexing agent at the end point and the concentration of the analyte can be calculated. The method is highly sensitive and does not require a metal indicator. Results: Through the determination of 5 × 10 -5 mol / L of calcium ions, the paper discusses the choice of experimental points and regression parameters. Since metal ions complexed with EDTA interfere with the assay, they must be hidden and separated. The accuracy of this method is satisfactory. The relative standard deviations (RSDs) of three determinations in parallel are not more than 2%, and the recoveries are about 10 1 2% -10 5 4%