电流反馈的高次微分示波极谱滴定法

在高次微分示波极谱滴定法中,利用电流反馈技术对充电电流进行补偿,可使高次微分示波极谱图上去板剂切口的灵敏度进一步提高。当切口电位处的|dC_d/dE|或|d²C₄/dE²|值相对较小时,电流反馈的作用就较明显。利用电流反馈高次微分示波极谱滴定法以氨羧络合剂滴定了Cd²⁺、Ni²⁺、Co²⁺、Pb²⁺、Zn²⁺,用Zn²⁺返滴定法测定了Al-Ni合金中的Ni,终点变化敏锐。

Oscillopolarographic Titrations Using Higher Order Differentiation and Feeding Back Current

In some cases, feeding back a current proportional to dE/dt will make the incision on the higher order differentiation more sensitive. The end-point will be very sharp. Smaller | dCcdE | and | d2Ca/dE2| values at the incision potential make the incision sensitivity increase to a greater extent by feeding back a current. Using ion incisions on the higher order differentiations to indicate the end-point of titrations, Cd2+, Ni2+, Co2+, Pb2+ and Zn2+ can be directly titrated with EDTA or CyDTA, Ni in Al-Ni alloy can be accurately determined by addition of excess EDTA followed by back titrations of the excess amount with Zn2+.