title: Fitting-free curve resolution of spectroscopic data: Chemometric and physical chemical viewpoints.
abstract: In this paper the authors have investigated spectroscopic data analysis according to a recent development, i.e. the Direct Inversion in the Spectral Subspace (DISS) procedure. DISS is a supervised curve resolution technique, consequently it can be used once the spectra of the potential pure components are known and the experimental spectrum of a chemical mixture is also presented; hence the task is to determine the composition of the unknown chemical mixture. In this paper, the original algorithm of DISS is re-examined and some further critical reasoning and essential developments are provided, including the detailed explanations of the constrained minimization task based on Lagrange multiplier regularization approach. The main conclusion is that the regularization used for DISS is needed because of the possible shifted spectra effect instead of collinearity; and this new property, i.e. treating the mild shifted spectra effect, of DISS can be considered as its main scientific advantage.
authors: Institute of Process Engineering, Faculty of Engineering, University of Szeged, H-6725 Szeged, Moszkvai krt. 5-7, Hungary. Electronic address: rajko@sol.cc.u-szeged.hu.
authors: Róbert
authors: R
authors: Rajkó
authors: Institute of Process Engineering, Faculty of Engineering, University of Szeged, H-6725 Szeged, Moszkvai krt. 5-7, Hungary; Department of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Zanjan, Iran.
authors: Samira
authors: S
authors: Beyramysoltan
authors: Department of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Zanjan, Iran.
authors: Hamid
authors: H
authors: Abdollahi
authors: Laboratory of Organosilicon Chemistry, Institute of Chemistry, Eötvös Loránd University, H-1518 Budapest 112, P.O.B. 32, Hungary.
authors: János
authors: J
authors: Eőri
authors: Laboratory of Organosilicon Chemistry, Institute of Chemistry, Eötvös Loránd University, H-1518 Budapest 112, P.O.B. 32, Hungary. Electronic address: pongor@chem.elte.hu.
authors: Gábor
authors: G
authors: Pongor
keywords: Closure; Collinearity; Direct inversion in the spectral subspace; Regularization; Shifted spectra effect; Unsupervised curve resolution