选择掩蔽配位滴定测定易熔合金中的镉

Determining Cd in Colliquable Alloy by Shielding Alternatively Complexometril Titration

先用过量的EDTA络合Cd2+和其它金属阳离子,用Pb(NO3)2标准溶液滴定过量的EDTA,然后加入邻菲啉作为释放剂分解Cd EDTA,释放出的EDTA再用Pb(NO3)2标准溶液返滴定,在pH=5～6时,以二甲酚橙为指示剂,滴定终点颜色变化敏锐,准确度高、精密度好,该方法用于易熔合金中镉的测定,结果令人满意。

Cd^( 2+) and other metal cation are complexed with EDTA.The surplus EDTA is titrated with standard solution Pb(NO_3)_2, then Cd-EDTA is decomposed by o-phenanthroine which is as releasing agent.The released EDTA is irritated with standard solution Pb(NO_3)_2,When pH value equals to 5～6,XO as indicator the color changes accurately and owing good accuracy high precision at the end point of titration.The method is used to determine Cd in colliquable alloy and the outcome turns up trumps.