Application of HPLC and Dual Wavelength Detection to the Analysis of Phenolic Compounds in Apples

Abstract

High-performance liquid chromatography, coupled with a programmable UV/visible detector, was applied to the identification and quantification of the phenolic compounds of apple tissue. The identity and purity of unknown components eluted from the HPLC column were established by comparing retention times and absorbance ratios with those of authentic compounds. In Golden Delicious apples, components with retention times agreeing with those of authentic catechin, epicatechin, chlorogenic acid, protocatechuic acid, p-hydroxybenzoic acid, p-coumaric acid, ferulic acid, and sinapic acid were found. However, comparison of absorbance ratios with those of authentic compounds suggested that many of the components that eluted in this system as single, symmetrical peaks were mixtures rather than individual compounds. This method helped to eliminate inaccurate identifications or faulty assumptions about homogeneity of HPLC “peaks”, errors that can occur when traditional HPLC methods that rely solely on detection at a single wavelength are employed. The method should have general applicability to plant extracts.