钙镁离子在络合滴定中的终点误差研究

Study on The End Point Error of Calcium and Magnesium in Complexometric Tritration

ＥＤＴＡ络合滴定法可准确滴定钙镁总量，但是滴定单一离子钙时则产生严重系统误差．作者采用化学计量学与传统化学分析相结合的方法，提出了钙镁两种混合离子的ｐＭｔ之间存在相关关系并进行数学模拟，求得ＥＤＴＡ滴定混合离子的终点误差，得出了混合离子滴定的终点误差小于单一离子滴定的终点误差的结论．本法为提高络合滴定准确度的应用研究提供了理论依据。

Abstract EDTA complexometric titration can contribute to the exact titration of the total quantity of calcium and magnesium but is apt to result in a serious system error when titrating single calcium ion We studied the “interrelation” between the pM t of the two mixed ions (calcium and magnesium) Through the combination of chemical metrology and the traditional chemical analysis,and also conducting mathematical simulation;we enventually sought out the error of the end point of the EDTA titration of the mixed ions and came to the conclusion that the error of the end point of the titration of the mixed ions is smaller than that of the titration of the single ion This work provided a theoretical basis for the application and research on raising the accuracy of the complexometric titration and at the same time presented universal and pratical significance in the research of the error of the end point of EDTA titration of other mixed ions Key wrods end point error;pM t;interrelation;control end pointion