Application of Model-Based Rank Annihilation Factor Analysis in Complex Formation Systems and Comparison of the Results with Hard and Soft Modeling Methods

Abstract

In present work, rank annihilation factor analysis was used to determine the formation constants of complexes between 3,6-bis[(2-arsonophenyl)azo]-4,5-dihydroxy-2,7-naphthalenedisulphonic acid disodium salt Arsenazo(III) and 13 lanthanides. The applicability of rank annihilation factor analysis for resolving the three competitive complex formation equilibria with large spectral overlapping of the three complex species was shown by comparison of the results with those obtained with the hard- and soft-modeling methods, which show satisfactory agreement between the results. The results showed that all the 13 lanthanides (M) studied form similar type of complexes and spectral profiles with Arsenazo (III) (L). For each of them, the three formation constants correspond, respectively, to M to L ratios of 1:1, 1:2 and 2:2.