title: Column-switching high-performance liquid chromatographic assay for the determination of quercetin in human urine with ultraviolet absorbance detection.
abstract: A high-performance liquid chromatographic method is described for the determination of quercetin in human urine using column-switching and ultraviolet (UV) absorbance detection. Urine samples were enzymatically hydrolysed and solid-phase extracted prior to injection onto the high-performance liquid chromatography (HPLC) system. Prior to elution of quercetin and the internal standard, fisetin. from the first column used for sample clean-up, the six-port valve was switched to the second column for analysis with UV detection. Detection of quercetin was accurate and reproducible, with a detection limit of 5 ng/ml. The method was applied to determine the urinary level of quercetin in 120 samples from an intervention study with fruit juice.
authors.affiliation: Institute of Toxicology, Danish Veterinary and Food Administration, Søborg.
authors.forename: S E
authors.initials: SE
authors.lastname: Nielsen
authors.forename: L O
authors.initials: LO
authors.lastname: Dragsted
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000032:analysis; D044948:Flavonols; D006027:Glycosides / Q000652:urine; D006801:Humans; D006868:Hydrolysis; D011794:Quercetin / Q000652:urine*; D012015:Reference Standards; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005419:Flavonoids; D044948:Flavonols; D006027:Glycosides; D011794:Quercetin; C017875:fisetin