Front-face fluorescence spectroscopy combined with second-order multivariate algorithms for the quantification of polyphenols in red wine samples

Abstract

The potential of front-face fluorescence spectroscopy combined with second-order chemometric methods was investigated for the quantification of the main polyphenols present in wine samples. Parallel factor analysis (PARAFAC) and unfolded-partial least squares coupled to residual bilinearization (U-PLS/RBL) were assessed for the quantification of catechin, epicatechin, quercetin, resveratrol, caffeic acid, gallic acid, p-coumaric acid, and vanillic acid in red wines. Excitation-emission matrices of different red wine samples, without pretreatment, were obtained in front-face mode, recording emission between 290 and 450 nm, exciting between 240 and 290 nm, for the analysis of epicatechin, catechin, caffeic acid, gallic acid, and vanillic acid; and excitation and emission between 300-360 and 330-400nm, respectively, for the analysis of resveratrol. U-PLS/RBL algorithm provided the best results and this methodology was validated by an optimized liquid chromatographic coupled to diode array and fluorimetric detectors procedure, obtaining a very good correlation for vanillic acid, caffeic acid, epicatechin and resveratrol.

Keywords: (+)-Catechin (PubChem CID: 9064); 3,4′,5-Trihydroxystilbene (Resveratrol) (PubChem CID: 445154); Caffeic acid (PubChem CID: 689043); Epicatechin (PubChem CID: 72276); Excitation-emission matrices; Front-face fluorescence; Gallic acid (PubChem CID: 370); Parallel factor analysis; Polyphenols; Unfolded partial least squares; Vanillic acid (PubChem CID: 8468); Wine.