11] Reversed-phase high-performance liquid chromatography methods for analysis of wine polyphenols

Abstract

Publisher Summary This chapter describes the reversed-phase high-performance liquid chromatography (HPLC) methods for the analysis of wine polyphenols. The analysis of phenolic compounds in any sample is a complex issue for a number of reasons. There are a number of well-established procedures designed to analyze all phenolic compounds as a single value (total phenol) or specific classes (i.e., total flavan-3-ol), but in every case there are differential responses (based on mass or molarity) related to different functional groups. The variability of the response can be small or large depending on the sample. The three procedures described in this chapter are (1) pH shift procedure, (2) low pH procedure, and (3) polystyrene column. Comparing the three methods, two silica gel reversed-phase systems have very similar elution orders, whereas the polystyrene column has a quite different pattern. In the latter case, polar anthocyanins and hydroxy cinnamates come out earlier, whereas nonpolar flavonols come out later. Thus, HPLC methods can separate major small phenolic constituents of wine in hour-long separations.