Local resolution of two-way data from multicomponent equilibria

• Published in: Analytica chimica acta Vol. 562; no. 1; pp. 94 - 102
• Main Authors: Abdollahi, H., Sorouraddin, M.H., Naseri, A.H.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 09-03-2006; Elsevier
• Subjects: Analytical chemistry; Chemistry; Exact sciences and technology; Fixed size moving window evolving factor analysis (FSMWEFA); Local resolution; Orthogonal projection resolution (OPR); Local resolution; Orthogonal projection resolution (OPR); Fixed size moving window evolving factor analysis (FSMWEFA); Spectral data; Chemical equilibrium; Equilibrium constant; Factor analysis; Multicomponent analysis; Fixed size moving window evolving factor analysis (FSMWEFA): Orthogonal projection resolution (OPR); Spectral line overlapping; Dissociation; Modeling
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2005.12.045

A self-modeling curve resolution (SMCR) method is proposed to calculate concentration and spectral profiles for the two-way spectral data from an equilibrium containing several chemical components. The proposed method has three main distinctive steps: (i) fixed size moving window evolving factor analysis (FSMWEFA) is used to identify the selective and zero concentration regions for a desired component, (ii) orthogonal projection resolution (OPR) is used to calculate its concentration profile and (iii) the component striping is done directly to resolve other components. The results of simulated and real polyprotic acid dissociation equilibria showed that the proposed combined method performs well even in situation when the successive stepwise equilibrium constants are close to each other. The applicability of method for resolving the triprotic acid system with rank deficiency due full spectral overlapping of two involved chemical species also is shown.