title: Determination of S-carboxymethylcysteine in serum by reversed-phase ion-pair liquid chromatography with column switching following pre-column derivatization with o-phthalaldehyde.
abstract: A method is described for the determination of S-(carboxymethyl)-L-cysteine in serum. After addition of S-(carboxyethyl)-L-cysteine as internal standard, both compounds are extracted into methanol, converted into fluorescent derivatives with o-phthalaldehyde and quantitatively determined by reversed-phase high-performance liquid chromatography. Chromatography of unwanted amino acid derivatives is avoided by column switching, thereby shortening analysis time and increasing column lifetime. The technique was applied in a study of the bioavailability of S-(carboxymethyl)-L-cysteine after oral administration to humans. The concentration-response curve was linear from 2 to 16 micrograms/ml; mean serum concentrations are reported.
authors.affiliation: Department of Pharmaceutical Chemistry and Drug Quality Control, State University of Ghent, Belgium.
authors.forename: J A
authors.initials: JA
authors.lastname: De Schutter
authors.forename: G
authors.initials: G
authors.lastname: Van der Weken
authors.forename: W
authors.initials: W
authors.lastname: Van den Bossche
authors.forename: P
authors.initials: P
authors.lastname: de Moerloose
mesh_terms: D002233:Carbocysteine / Q000097:blood* / Q000493:pharmacokinetics; D002853:Chromatography, Liquid; D003545:Cysteine / Q000031:analogs & derivatives*; D006801:Humans; D007202:Indicators and Reagents; D009764:o-Phthalaldehyde
chemical_list: D007202:Indicators and Reagents; D009764:o-Phthalaldehyde; D002233:Carbocysteine; D003545:Cysteine