Online photocatalytic device for highly selective pre-column fluorescence derivatization of 5-hydroxyindoles with benzylamine

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• 作者：Kenichiro Todoroki ; Yoshihiko Nakashima ; Hideyuki Yoshida ; Hitoshi Nohta and Masatoshi Yamaguchi
• 关键词：5-Hydroxyindole ; 5-Hydroxyindole-3-acetic acid ; Liquid chromatography ; Titanium dioxide ; Photocatalyst ; Fluorescence derivatization
• 刊名：Analytica Chimica Acta
• 出版年：2006
• 出版时间：5 January 2006
• 年：2006
• 卷：555
• 期：1
• 页码：14-19
• 全文大小：144 K

文摘

A fluorimetric liquid chromatographic method for the determination of 5-hydroxyindoles based on the benzylamine derivatization process mediated through an online photocatalytic oxidation has been developed. In this study, we used a photocatalytic column comprising tefzel tubing packed with TiO₂-coated glass beads, as a pre-column derivatization reactor. The fluorescence derivatization of 5-hydroxyindoles using benzylamine proceeded during their passage through the reaction column under near-UV irradiation. The 5-hydroxyindole derivatives were separated continuously on a reversed-phase liquid chromatography within 50 min, using 100 mM acetate buffer (pH 4.6)–acetonitrile (72:28, v/v; isocratic elution) containing 3 mM sodium octanesulfonate; the samples were detected fluorimetrically at 465 nm upon excitation at 350 nm. The detection limits (signal-to-noise ratio = 3) of the 5-hydroxyindoles were in the range from 160 to 360 fmol per 5 μL injection. We have applied this method, which requires minimal sample pre-treatment, to the determination of 5-hydroxyindole-3-acetic acid in human urine.