ANALYSIS OF FLAVONOIDS AND HYDROXYCINNAMATES IN CITRUS PROCESSING BYPRODUCTS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY- ELECTROSPRAY IONIZATION-MASS SPECTROMETRY

摘要

Electrospray ionization-high performance liquid chro-matography-mass spectrometry (ESI-HPLC-MS) greatly facilitates analyses of the complex phenolic constituents of citrus peel and associated citrus processing byproducts. The numerous flavonoid glycosides and polymethoxylated flavones (PM-Fs) in these materials can be readily detected by positive ion ESI mode. Single ion monitoring (SIM) mode allows for selective detection and enhanced quantitation of the PMFs and other flavonoid glycosides in spiteof incomplete chromatographic peak separations. Flavonoid-O-glycosides fragment with source cone voltages in ways that confirm structural assignments. These fragmentation patterns allow for the detection of other trace-occurring chemical species with specific flavonoid components. Many of the hydroxycinnamates are best detected by the ESI negative ion mode. However, the fragmentation patterns obtained with positive ESI allow structural information to be obtained for individual components of this complex group of compounds.