等电位间隔-电位滴定法

Potentiometric Titration by the Equi-potential Interval Method

对两点电位滴定法作出改进,提出了等电位间隔-电位滴定法。由数学推导证明,当P1的数值(P1为V1与Ve的比值以百分率表示;V1为在第1测量点所耗滴定剂的体积;Ve为滴定终点时所耗滴定剂的体积)达到95%,且在两点间的电位差值(ΔE)大于30mV时,滴定的相对误差(T)的计算值可达到小于0.1%。据此,在滴定过程中,记录两测量点之间的ΔE为30mV时的V及E值,当有两组数据的ΔE达到30mV并算得此时的T值≤0.1%时,即可停止滴定,并根据所给公式计算Ve及滴定结果。将此方法应用于包括中和反应、沉淀反应及氧化还原反应等多种滴定体系的电位滴定,所得结果与常规电位滴定法的测定结果一致。

As a modification for the two-point potentiometrie titration, the equi-potential interval method was proposed in this paper. It was proved by mathematical derivation, that when P1 （ratio of V1 to V, expressed in %; V1 is the volume of titrant consumed at the 1st point of measurement, and Ve is the volume of titrant consumed at the end-point of titration） achieved to a value of 95%, and the potential difference （△E） between the 2 points was greater than 30 mV, the relative error T would be less than 0. 1%. Based on these facts, values of V and E were taken through the titration at intervals of△E of 30 mV, and the titration was concluded when the calculated values of T attained to ≤0.1%. Values of Ve and results of titration were calculated by the formula given. Results obtained in applying the present method to the potentiometrie titration of neutralization, precipitation and redox reaction systems, were in consistency with the conventional potentiometrie titration.