title: Fully automated reagent peak-free liquid chromatography fluorescence analysis of highly polar carboxylic acids using a column-switching system and fluorous scavenging derivatization.
abstract: In this study, we combined a column-switching system with a fluorous scavenging derivatization method to develop a fully automated reagent peak-free LC fluorescence detection protocol for the analysis of highly polar carboxylic acids. In this method, highly polar carboxylic acids were derivatized with fluorescent 1-pyrenemethylamine in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 1-hydroxy-1H-benzotriazole. Residual excess of the unreacted reagent was tagged with 2-(perfluorooctyl)ethyl isocyanate and then removed selectively using a fluorous column-switching system placed in front of an analytical reversed-phase column. The signal of the fluorous-tagged unreacted reagent was completely absent in the resulting chromatograms; therefore, it did not interfere with the quantification of each acid especially those eluted before 20 min. The detection limits (S/N = 3) for the examined acids were in the range from 4.0 to 22 fmol per injection. We have applied this method to comparative analysis of highly polar carboxylic acids in urine samples obtained from diabetes mellitus type-II model mice and their control.
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Suruga-ku, Shizuoka, Japan. todoroki@u-shizuoka-ken.ac.jp
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Todoroki
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Machida
authors.forename: Miki
authors.initials: M
authors.lastname: Itoyama
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hayama
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Yoshida
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nohta
authors.forename: Manabu
authors.initials: M
authors.lastname: Nakashima
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D001331:Automation; D002264:Carboxylic Acids / Q000737:chemistry* / Q000652:urine; D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D003924:Diabetes Mellitus, Type 2 / Q000652:urine; D005453:Fluorescence; D006801:Humans; D008297:Male; D051379:Mice
chemical_list: D002264:Carboxylic Acids