光度法测定造币镀液及其废液中的铁和镍

Determination of Iron and Nickel in Coin-making Plating Solution and Its Waste by Spectrophotometry

在酸性介质中 ,Fe3+ 与磺基水杨酸络合物的吸收峰在 51 0nm处 ,在此波长处大量Ni2 + 的吸收最弱 ,而Ni2 + 在 72 0nm处出现吸收峰 ,此处铁的络合物的吸收亦很弱 ,据此建立了题示样品中铁和镍的光度分析方法。铁和镍的相互干扰可用数学计算法加以消除 ,其它共存离子不干扰测定。测定造币镀液及其废液样品中铁和镍的相对标准偏差 (n =5)分别 <2 .5%和<1 .8% ,加标回收率分别为 97.0 %～ 1 0 2 .1 %和 97.4 %～ 1 0 1 .6%。

In acid solution the absorbance of Ni at 510 nm, which is the maximum absorption wavelength for the complex of Fe 3+ with sulfosalicylic acid, is the lowest. And absorbance of the complex of Fe 3+ with sulfosalicylic acid at 720 nm, which is the maximum absorption wavelength of Ni 2+ , is very low. Based on these facts, a spectrophotometric method for the determination of Fe and Ni in coin making plating solution and its waste has been proposed. The interference between Fe 3+ and Ni 2+ can be eliminated by mathematical calculation method. And no interference from other coexistent elements on the determination of Fe and Ni were observed. The method has been applied to the determination of Fe and Ni in coin making plating solution and its waste. Recoveries of standard additions for Fe and Ni are 97.0%～102.1% and 97.4%～101.6% with precision (RSD, n =5) of <2.5% and <1.8% respectively.