Analysis of phenolic compounds in Muscatel wines produced in Portugal

A liquid chromatography method associated with mass spectrometry and diode array, fluorescence and electrochemical detectors was used in order to study phenolic composition of Muscatel sweet wines from Setúbal region in Portugal. Samples were collected during winemaking production at different representative producers of this region. Total phenolic contents of samples were also determined using the Folin–Ciocalteu method. Mass spectrometry results show that atmospheric pressure chemical ionisation (APCI) in negative mode presents higher sensitivity for the majority of the compounds studied. Some phenolic acids, stilbenes as resveratrol and piceid, and flavonols as quercetin and quercetin glycosides were identified in these Muscatel wines. For resveratrol, piceid, gallic acid, protocatechuic acid, catechin and quercetin, fluorescence and electrochemical properties were used as complementary or alternative methods of detection. Differences in phenolic composition and total phenolic contents were found among samples collected.