Identification of Phenolic Compounds in Walnut Samples by Capillary Electrophoresis-Electrospray Ionization-microTOF

Walnuts (Juglans regia L.) are a good source of essential fatty acids, tocopherols and phenolic compounds that contribute to reduce the risk of coronary heart disease, and also inhibit the oxidation of human plasma and low density lipoproteins. In this work the applicability of fast analytical determinations by capillary electrophoresis coupled with microTOF was utilized to identify different phenolic compounds (phenolic acids and flavonoids) in walnut samples. Materials and methods Different extraction systems were studied to evaluate their extraction capacity of phenolic compounds. Analyses of the phenolic fraction were done using a Beckman capillary electrophoresis instrument P/ACETM System MDQ (Beckman Instruments, Inc., Fullerton, CA, USA) equipped with a microTOFTM (Bruker Daltonik, Bremen, Germany). Results The extraction system that produced the best results was ethanol. Because of that, ethanolic extracts of walnut were analized and the phenolic compounds identified on them were chlorogenic acid, p-coumaric acid, ferulic acid, ellagic acid and ellagic acid pentoside, syringic acid, vanillic acid, p-coumaroylquinic acid, catechin The individual phenolic compounds were identified by the accurate mass data of the molecular ion that were processed through the software DataAnalysis 3.4 (Bruker Daltonik GmbH), which a list of possible elemental formula by using the GenerateMolecularFormulaTM editor. Conclusions Capillary electrophoresis time-of-flight mass spectrometry is a powerful new technique that can be used to rapidly (in less than 15 min) identify and quantify possible bioactive compounds in walnut.