Luminescent determination of flavonoids in orange juices by LC with post-column derivatization with aluminum and terbium

• Published in: Journal of separation science Vol. 33; no. 4-5; pp. 509 - 515
• Main Authors: Andreu-Navarro, Alvaro, Fernández-Romero, Juan Manuel, Gómez-Hens, Agustina
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley-VCH Verlag 01-03-2010; WILEY-VCH Verlag; WILEY‐VCH Verlag; Wiley
• Subjects: Aluminum; Aluminum - chemistry; Aluminum and terbium complexes; Biological and medical sciences; Chelating Agents - chemistry; Chromatography, Liquid - instrumentation; Chromatography, Liquid - methods; Flavonoid compounds; Flavonoids; Flavonoids - analysis; Flavonoids - chemistry; Food industries; Fruit - chemistry; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Juices; Mathematical models; Molecular Structure; Non alcoholic beverage industries and mineral waters; Orange juices; Oranges; Plant Extracts - chemistry; Post-column derivatization; Separation; Spectrometry, Fluorescence; Terbium; Terbium - chemistry; Time Factors; Wavelengths; Post-column derivatization; Complexation; Chemical analysis; Aluminium III Compounds; Aluminum and terbium complexes; HPLC chromatography; Terbium Complexes; Derivatization; Flavonoid; Postcolumn; Orange juices; Metal Complexes; Aluminium Complexes; Orange juice; Flavonoid compounds; Luminescence spectrometry; Lanthanide Complexes; Beverage; Terbium III Compounds; Quantitative analysis
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.200900696

A new post-column derivatization system is described and applied to the determination of flavonoids in citric beverages after their separation by LC using a monolithic column. The derivatization involves the formation of the chelates of the analytes with aluminum (III) and terbium (III) in the presence of the surfactant SDS and the measurement of the terbium sensitized luminescence at λex 360 and λem 545 nm. Naringin, hesperidin, quercetin, naringenin, and kaempferol have been chosen as analyte models. The large Stokes shift and the relatively long wavelength emission of terbium(III) can minimize interferences from background sample matrix, which usually emit at shorter wavelengths. Calibration graphs were constructed in the intervals 6.0-1700 ng/mL naringin, 9.8-1700 ng/mL hesperidin, 2.1-2000 ng/mL quercetin, 5.2-1500 ng/mL naringenin and 2.5-2000 ng/mL kaempferol, with regression coefficients higher than 0.9935 in all instances. The precision of the method, expressed as RSD%, was established at two concentration levels, with values of 1.3 and 4.7%, which corresponded to the minimal and maximal error zones of the calibration graphs. The practical usefulness of the method is demonstrated by the analysis of orange juices, which were diluted and directly injected into the chromatographic system, obtaining recoveries between 86.9 and 108.2%.