title: Fluorescence properties of flavonoid compounds. Quantification in paprika samples using spectrofluorimetry coupled to second order chemometric tools.
abstract: The influence of pH on the fluorescence of flavonoid compounds was investigated and the highest fluorescence emission was obtained in basic medium. Selected conditions to improve this signal were: pH 9.5, 0.14 M Britton Robinson buffer and methanol between 5% and 10%. The excitation-emission fluorescence matrices of a set of 36 samples of Spanish paprika were analyzed by means of parallel factor analysis (PARAFAC). Thus, the profiles of possible fluorescence components (PARAFAC loadings) were obtained. One of these profiles was identified by matching PARAFAC scores with LC analysis on the same samples. Two clusters of samples were obtained when score values were plotted against each other. Spectrofluorimetry coupled to second order multivariate calibration methods, as unfolded-partial least squares with residual bilinearization (U-PLS/RBL) and multidimensional-partial least-squares with residual bilinearization (N-PLS/RBL), was investigated to quantify quercetin and kaempferol in those samples. Good results were obtained for quercetin by this approach.
authors.affiliation: Department of Analytical Chemistry and IACYS, University of Extremadura, Badajoz 06006, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Monago-Maraña
authors.affiliation: Department of Analytical Chemistry and IACYS, University of Extremadura, Badajoz 06006, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Durán-Merás
authors.affiliation: Department of Analytical Chemistry and IACYS, University of Extremadura, Badajoz 06006, Spain. Electronic address: tgaleano@unex.es.
authors.forename: Teresa
authors.initials: T
authors.lastname: Galeano-Díaz
authors.affiliation: Department of Analytical Chemistry and IACYS, University of Extremadura, Badajoz 06006, Spain.
authors.forename: Arsenio
authors.initials: A
authors.lastname: Muñoz de la Peña
mesh_terms: D002212:Capsicum / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry*; D005453:Fluorescence; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D005419:Flavonoids
keywords: Flavonoids; Fluorescence; Kaempferol (PubChem CID: 5280863); Multidimensional-partial least-squares with residual bilinearization; Myricetin (PubChem CID: 5281672); Paprika; Parallel factor analysis; Quercetin (PubChem CID: 5280343); Unfolded-partial least-squares with residual bilinearization