De Schutter J A, Van der Weken G, Van den Bossche W, de Moerloose P
Department of Pharmaceutical Chemistry and Drug Quality Control, State University of Ghent, Belgium.
J Chromatogr. 1988 Jul 15;428(2):301-10. doi: 10.1016/s0378-4347(00)83921-3.
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.
