Study of Complex Formation between 4-(2-Pyridylazo) Resorcinol and Al³⁺, Fe³⁺, Zn²⁺, and Cd²⁺ Ions in an Aqueous Solution at 0.1 M Ionic Strength

Abstract

The complexation reactions between 4-(2-pyridylazo)resorcinol (PAR) and Al 3+ , Fe 3+ , Zn 2+ , and Cd 2+ ions at 25 °C and 0.1 M ionic strength are performed spectrophotometrically. A critical comparison of the various PCA methods on the absorbance matrix data concerning the number of light-absorbing species has been made. Knowing the number of light-absorbing species is a critical step for subsequent quantitative and qualitative solution equilibria studies. Therefore, the nine selected index functions for the prediction of the number of light-absorbing components which contribute to a set of spectra are critically tested using the algorithms implemented in INDICES software. Behind the number of various complexes formed the stability constants of species ML and MLH, type log β 110 and log β 111 , for the system of PAR (ligand L) with Zn 2+ and Cd 2+ ions and the stability constants of species MLH and ML 2 H, type log β 111 and log β 121 , for the system of PAR (ligand L) with Al 3+ and Fe 3+ ions at 25 °C and 0.1 M ionic strength, and various mole ratios are estimated by the SQUAD and EQUISPEC programs.

Application of 4-(2-pyridylazo)resorcinol for flotation-spectrophotometric determination of iron

“…Complexes of Fe II or Fe III and PAR have been investigated and by many authors [2][3][4][5][6][7][8][9][10][11]. Sometimes, the authors' opinions on various issues concerning the composition, iron oxidation state, or solubility of the complexes in different solvents are contradictory.…”

A rapid, automated gradient flow injection–spectrophotometric technique for study of metal complexation reactions

“…The Stability Quotients from Absorbance Data (SQUAD) program was written in FORTRAN by Leggett et al [13,24,43], and they for the first time used a factor analysis method for determination of stability constants [44]. SQUAD uses non-linear least-squares for calculation of stability constants.…”

DNA-binding study of anthraquinone derivatives using Chemometrics methods

“…The data obtained by INDICES analysis have more validity than those obtained by PCA method because in INDICES analysis nine function with nine characteristics were used for deducing the final results. Furthermore, INDICES analysis in comparison to PCA method is more easy to use [55]. According to the following model four species are including free DNA, free dye and two types of DNAedye complexes formed in solution.…”

“…Procedures for determining the chemical rank of a matrix using a variety of empirical and statistical methods based on principal component analysis (PCA) have been reported [53]. In order to determine the number of light-absorbing species in the recorded spectral data matrix the INDICES [54] and PCA [55] programs were used. The INDICES program was introduced by Meloun et al [54].…”