Simultaneous determination of main phenolic acids and flavonoids in tomato by micellar electrokinetic capillary electrophoresis

Abstract

A methodology for the determination of tomato phenolic acids and flavonoids has been developed combining MEKC and DAD detection. The influence on polyphenol separation of pH and background electrolyte, BGE (borax, acetonitrile, methanol and SDS concentrations), was studied and optimized using response surface methodology and weighted desirability function. Separation of polyphenols was achieved within 20 min at 15 °C using 11.3 mM borax and 11.2 mM SDS adjusted to pH 8.5 as BGE. Validation was performed using standards and tomato extracts. Recoveries ranged from 77 to 106%. Acceptable repeatabilities were obtained for peak area (%RSD <3.1% and <3.7%) and migration times (%RSD <0.2% and <1.4%) for intra- and inter-day respectively. Detection limits ranged between 0.8 and 3.8 mg kg−1. Five and seven of these polyphenols were determined in samples of tomato and related species. This methodology will be valuable tool in breeding programs, analyzing a large number of samples.