Liquid chromatographic determination of polythiols based on pre-column excimer fluorescence derivatization and its application to alpha-lipoic acid analysis.
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.
Inoue
Takashi
T
Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Johnan, Fukuoka 814-0180, Japan.
Sudo
Maki
M
Yoshida
Hideyuki
H
Todoroki
Kenichiro
K
Nohta
Hitoshi
H
Yamaguchi
Masatoshi
M
D002853:Chromatography, Liquid / Q000295:instrumentation* / Q000379:methods*; D013058:Mass Spectrometry; D008962:Models, Theoretical; D013438:Sulfhydryl Compounds / Q000032:analysis*; D008063:Thioctic Acid / Q000032:analysis*
D013438:Sulfhydryl Compounds; D008063:Thioctic Acid