Fluorescence detection of flavonols in HPLC by postcolumn chelation with aluminum

Peter C H Hollman, J. M P Van Trijp, Michel N C P Buysman

Research output: Contribution to JournalArticleAcademicpeer-review


Flavonols are dietary antioxidants which may prevent coronary heart disease. To be able to study absorption of flavonols in humans, we developed a postcolumn derivatization with aluminum for HPLC with fluorescence detection. Variables governing postcolumn chelation, such as water content, buffer, organic modifier of the eluent, concentration of Al3+, presence of acetic acid in the postcolumn reagent, and temperature, were studied and optimized. Of the flavonoids, only flavonols that contain a free 3-hydroxyl and 4-keto oxygen binding site form fluorescent complexes with Al3+. The method has a detection limit of 0.15 ng/mL for quercetin, 0.05 ng/mL for kaempferol, 0.45 ng/mL for myricetin, and 0.05 mg/mL for isorhamnetin, thus improving detectability of quercetin 300-fold as compared to that possible with UV detection. The reproducibility relative standard deviation of the method is 1.4%. This extremely sensitive method enables, for the first time, determination of flavonols in body fluids after consumption of a normal diet.

Original languageEnglish
Pages (from-to)3511-3515
Number of pages5
JournalAnalytical Chemistry
Issue number19
Publication statusPublished - 1 Oct 1996


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