title: New strategy to identify radicals in a time evolving EPR data set by multivariate curve resolution-alternating least squares.
abstract: Electron paramagnetic resonance (EPR) spectroscopy is a powerful technique that is able to characterize radicals formed in kinetic reactions. However, spectral characterization of individual chemical species is often limited or even unmanageable due to the severe kinetic and spectral overlap among species in kinetic processes. Therefore, we applied, for the first time, multivariate curve resolution-alternating least squares (MCR-ALS) method to EPR time evolving data sets to model and characterize the different constituents in a kinetic reaction. Here we demonstrate the advantage of multivariate analysis in the investigation of radicals formed along the kinetic process of hydroxycoumarin in alkaline medium. Multiset analysis of several EPR-monitored kinetic experiments performed in different conditions revealed the individual paramagnetic centres as well as their kinetic profiles. The results obtained by MCR-ALS method demonstrate its prominent potential in analysis of EPR time evolved spectra.
authors.affiliation: LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France.
authors.forename: Maya Abou
authors.initials: MA
authors.lastname: Fadel
authors.affiliation: Chemometrics Group, Section of Analytical Chemistry, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: de Juan
authors.affiliation: LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Vezin
authors.affiliation: LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France. Electronic address: ludovic.duponchel@univ-lille1.fr.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Duponchel
mesh_terms: D003374:Coumarins / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry*; D007700:Kinetics; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D013223:Statistics as Topic / Q000379:methods*; D013997:Time Factors
chemical_list: D003374:Coumarins; D005609:Free Radicals
keywords: Chemometrics; Electron paramagnetic resonance spectroscopy; Multiset analysis; Multivariate curve resolution-alternating least squares; Radicals