Extraction studies of metal complexes with some macrocyclic tetraaza ligands and xanthene dyes. Spectrophotometric determination of Cadmium(II) with Tetramethyltetraazacyclotetradecane and Erythrosin A

Authors:

• Walenty Szczepaniak,
• Bernard Juskowiak,
• Wanda Ciszewska

Abstract

The liquid-liquid extraction of ion-pair complexes of zinc(II), copper(II) and cadmium(II) is described. The macrocyclic ligands 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (4Me-cyclam-14) and rac-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (Tet b) are used with xanthene dyes as the counter ions. The apparent extraction constants (D′_c) are reported. The sequences of extraction efficiency of both ligands are related to the structure of the complexes. The apparent molar absorptivity of the Cd(4Me-cyclam-14)-erythrosin A ion-associate is 1.1 × 10⁵ l mol^- cm^-1. The calibration graph is linear over the range 0-10^-5 M, which allows even 0.05 μg ml^-1 cadmium to be determined in a 0.5 M sodium hydroxide medium. No interference was observed from Ni²⁺, Pb²⁺, Zn²⁺, Mg²⁺, Sn⁴⁺, Ga³⁺, Al³⁺ and Fe³⁺. Interferences were Cu²⁺, Hg²⁺, Ag⁺ and large anions. © 1984.