Volume 2, Issue 6 (June 2005)
Characterization and Analytical Application of the Ion-Association Complex of Nickel with Alizarin Yellow R and Eosin
The reaction of nickel (II) with [5-(4-nitrophenylazo)salicylic acid] Alizarin yellow R (AYR) as a primary ligand and eosin as a secondary ligand was studied spectrophotometrically in the presence of Tween 80, 50 % (v/v) ethanol-water medium and an ionic strength of 0.1 M (NaClO4). The solution spectra of the mixed-ligand complex formed are characterized by high intensity (ɛ = 3.3 × 105 L mol-1cm-1) charge transfer at 575 nm. The study reveals the formation of an ion-association complex having the composition Ni: AYR: eosin (2: 1: 2), and the corresponding molecular formula is (Ni)2(AYR)(eosin)2. The optimum conditions for the spectrophotometric determination of Ni (II) have been established. A simple, sensitive, and selective method was proposed for the determination of Ni (II). The method has been applied successfully for the micro determination of Ni(II) in pharmaceutical samples. The mechanism of the reaction was also discussed.