Effect of cationic surfactants on the complexation of lutetium(III) with 2,2′,3,4-tetrahydroxy-3′-sulfo-5′-nitroazobenzene

Abstract

The effect of cationic surfactants (CSs: cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr), and cetyltrimethylammonium bromide (CTABr)) on the complexation of lutetium(III) with 2,2′,3,4-tetrahydroxy-3′-sulfo-5′-nitroazobenzene (H4L) is studied. Homo-and mixed-ligand compounds form at pH 4. It is found that, as the stability of the associates increases (H4L-CPCl > H4L-CPBr > H4L-CTABr), the detection limit of lutetium(III) in the complexation reaction with H4L-CS decreases in the order Lu-H4L-CPCl > Lu-H4L-CPBr > Lu-H4L-CTABr and the stability constants of their complexes grow. The component ratio in the homo-and mixed-ligand complexes are found to be 1:1 and 1:1:1, respectively. The range of obedience to Beer’s law is determined. A procedure for determining lutetium(III) in model mixtures is developed.