title: Liquid chromatographic determination of polythiols based on pre-column excimer fluorescence derivatization and its application to alpha-lipoic acid analysis.
abstract: We developed an LC method for the sensitive and selective fluorometric determination of polythiols. This method employs pre-column intramolecular excimer-forming fluorescence derivatization with N-(1-pyrene)iodoacetamide followed by LC separation. Polythiols were converted to the corresponding dipyrene-labeled derivatives, and the derivatives afforded intramolecular excimer fluorescence (440-540 nm). After the optimization using dithiothreitol and dimercaprol as model polythiols, alpha-lipoic acid (LA) and alpha-lipoamide were determined with high sensitivity and selectivity. The detection limits for polythiols were 0.6-3.5 fmol on column. Furthermore, this method could be successfully applied to the determination of LA in commercial dietary supplements and in human urine.
authors.affiliation: Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Johnan, Fukuoka 814-0180, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Inoue
authors.forename: Maki
authors.initials: M
authors.lastname: Sudo
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Yoshida
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Todoroki
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nohta
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yamaguchi
mesh_terms: D002853:Chromatography, Liquid / Q000295:instrumentation* / Q000379:methods*; D013058:Mass Spectrometry; D008962:Models, Theoretical; D013438:Sulfhydryl Compounds / Q000032:analysis*; D008063:Thioctic Acid / Q000032:analysis*
chemical_list: D013438:Sulfhydryl Compounds; D008063:Thioctic Acid