Analytical Innovations in the Detection of Phenolics in Wines

Abstract

A liquid chromatographic method with online photometric and luminescent detection for the determination of 18 phenolic compounds in wines is reported. Photometric detection is performed at four wavelengths, namely, 256, 280, 320, and 365 nm, using a diode array detection system. The luminescent detection is achieved by means of a postcolumn derivatization reaction of 10 of these compounds with terbium(III) in the presence of synergistic agents, such as ethylenediaminetetraacetic acid (EDTA) and n-octyltriphosphine oxide (TOPO). A micellar medium provided by the surfactants sodium dodecyl sulfate and Triton X-100 was used for the determination of the luminescent chelates at lambdaex 317 and lambdaem 545 nm. The long wavelength emission of lanthanide chelates can minimize interferences from background sample matrix, which usually emit at shorter wavelengths. The analytical features of the photometric and fluorometric methods, such as dynamic ranges of the calibration graphs, detection limits, and precision data, have been obtained. The practical usefulness of the developed methods is demonstrated by the analysis of Spanish and Italian wine samples (red, rosé, oloroso, and white), which were diluted and directly injected into the chromatographic system. The accuracy of both methods was checked by assaying a recovery study, which was performed at three different analyte levels for each type of sample.

Quantification of glutathione, catechin and caffeic acid in grape juice and wine by a novel ultra-performance liquid chromatography method

“…The recovery for catechin was 98.7% and 111.3% in juice and white wine respectively, while that of caffeic acid was 111.3% and 85.8% in juice and wine. These recoveries achieved during evaluation of the method was in accordance with those reported in white wine for both catechin and caffeic acid when quantified by HPLC (Castellari et al, 2002;Russo, Andreu-Navarro, Aguilar-Caballos, Fernández-Romero, & Gómes-Hens, 2008).…”

Luminescent determination of flavonoids in orange juices by LC with post‐column derivatization with aluminum and terbium

“…Flavonoids have strong coordination ability toward a wide range of cations such as iron(II) 16, chromium(III) 17, aluminum(III) 14, 18–21, and lanthanide 13, 22, 23 ions, which is ascribed to the presence of multiple hydroxyl groups and the carbonyl group on the heterocyclic ring of their chemical structure. Experimental studies reveal that the preferred complexation sites for the flavonoids involve the hydroxyl group on carbon 3 or 5 and the adjacent 4‐carbonyl group 18–21.…”

“…The main separation technique applied to the determination of flavonoids in orange juices is LC 6–11, using reversed‐phase columns, although gas chromatography 12, involving the formation of trimethylsilyl derivatives, has been also described for this purpose. The usefulness of a monolithic column, which can operate at higher flow rates with lower backpressures than conventional columns, has been previously described for the LC separation of some flavonoids in wine samples 13. However, to the best of our knowledge, this type of column has not been used up to date for the determination of these compounds in orange juices.…”

“…Some flavonoids, such as quercetin and kaempferol, have been fluorimetrically determined in body fluids using aluminum(III) as post‐column derivatization reagent to obtain fluorescent chelates 14. Another post‐column derivatization system previously described for the determination of these compounds in wine samples involves the formation of the corresponding terbium(III) chelates and the measurement of the sensitized luminescence 13. This phenomenon is an intermolecular energy transfer process, in which the ligand acts as donor and terbium(III) acts as acceptor and emits luminescence, that allows very sensitive and selective determinations, although its use as detection system in LC has been relatively limited 15.…”

Rapid‐resolution liquid chromatography/mass spectrometry for determination and quantitation of polyphenols in grape berries

“…The occurrence of phenolics in grapes and wine has been extensively studied by high‐performance liquid chromatography (HPLC) with ultraviolet (UV), fluorescence, or mass spectrometric (MS) detection 9, 12, 20, 24, 27, 33–45. However, only a small number of phenolic compounds have been determined contemporaneously in these studies.…”