原卟啉-吐温80-硫酸铵液固体系分离和测定铜、镍的研究

Study on separation and determination of copper(Ⅱ) and nickelwith protoporphyrin-Tween-80-ammonium sulfate liquid-solid system

在表面活性剂吐温80存在下，pH9．5的NH3·H2O-H4Cl缓冲溶液中，原卟啉与Cu（Ⅱ）形成1：1的深红色络合物，该络合物能被吐温80-硫酸铵液固体系固相析出，从而使Cu（Ⅱ）和Ni（Ⅱ）分离，在569nm处分光光度法测定Ca（Ⅱ），原子吸收光谱法测定Ni（Ⅱ）。研究了原卟啉铜络合物的光谱特性、组成、稳定常数、形成和萃取分离条件，并对络合及萃取机理进行了探讨。方法对于铜的线性范围为0～15μg／mL（r=0．9995），检出限为0．0069μg／mL，已用于土壤样品中铜的测定。

In the presence of surfactant Tween-80 and in the medium of NH3· H2O-NH4Cl buffer solution at pH 9.5,protoporphyrin reacted with Cu（Ⅱ） to form a 1 ： 1 complex compound, which could be separated from Ni（Ⅱ） with Tween-80-（NH4）2SO4 liquid-solid system,and then Cu（Ⅱ） and Ni（Ⅱ） were determined by speetrophotometry at 569 nm and atomic absorption spectrometry, respectively. Spectrum character, composition, stability constant, separation conditions of the complex were discussed. The mechanism of eomplexation and extraction were studied as well. The linear range of the method was from 0 to 15μg/mL, and the detection limit was 0. 006 9 μg/mL for Cu（Ⅱ）. The proposed method has been applied to the separation and determination of copper and nickel in soil samples.