Simultaneous high-performance liquid chromatographic determination of catecholamine-related compounds by post-column derivatization involving coulometric oxidation followed by fluorescence reaction.
A highly selective and sensitive high-performance liquid chromatographic method for the determination of catecholamines (norepinephrine, epinephrine and dopamine) and related compounds (L-DOPA, normetanephrine, metanephrine, 3-methoxytyramine, 3,4-dihydroxymandelic acid, 3,4-dihydroxyphenylacetic acid, homovanillic acid, vanillylmandelic acid, 3,4-dihydroxyphenylethylene glycol, 4-hydroxy-3-methoxyphenylethylene glycol and 4-hydroxy-3-methoxyphenylethanol) with a post-column technique involving coulometric oxidation followed by fluorescence derivatization is described. These compounds, 3,4-dihydroxybenzylamine and ferulic acid are separated within 35 min by ion-pair reversed-phase chromatography using acidic buffers (pH 3.1) with methanol-acetonitrile (3:2, v/v) gradient elution, and then oxidized by a commercial coulometric detector to the corresponding o-quinones, which are converted into fluorescent derivatives by reaction with 1,2-diphenylethylenediamine. The detection limits (signal-to-noise ratio = 3) on-column are 1.5-4 pmol for the two mandelic acids, 600 fmol for L-DOPA and 20-70 fmol for the others.
Nohta
H
H
Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Yamaguchi
E
E
Ohkura
Y
Y
Watanabe
H
H
D002395:Catecholamines / Q000032:analysis*; D004563:Electrochemistry; D006801:Humans; D010084:Oxidation-Reduction; D013050:Spectrometry, Fluorescence
D002395:Catecholamines