Comprehensive Two-dimensional Liquid Chromatography Methods for Analysis of Polyphenols in Food

Phenols and flavonoids presenting an enormous structural variability are receiving special interest because of their broad spectrum of pharmacological effects. The identification of these polyphenol derivatives in food samples is a difficult task due to the complexity of the structures and the limited standards commercially available. So far, one-dimensional chromatography was the most widely applied analytical approach for their analysis. However, when dealing with very complex media, a single separation system often does not provide sufficient resolving power for attaining rewarding results. Comprehensive twodimensional Liquid Chromatography (LC×LC) is a technique of great analytical impact, since it offers much higher peak capacities than separations in a single dimension. The present review describes the applications carried out in the field of LC×LC for polyphenol separation in food and food-related products.