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Determination by liquid chromatography of free and total cysteine in human urine in the form of its S-quinolinium derivative by Edward Bald; Rafal Glowacki; Józef Drzewoski is a Chemistry article available to read on EtoBox.

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A reversed-phase high-performance liquid chromatographic method for the determination of free and total cysteine in urine is described. The method involves reductive conversion of cysteine dimer and cysteine mixed disulphides to their reduced counterpart with the use of tri-n-butylphosphine, ultraviolet-labeling with 2-chloro-1-methylquinolinium tetrafluoroborate, and liquid chromatographic separation with isocratic conditions. In developing this method the following parameters were investigated and optimized: the time, pH and reagent excess in the derivatization step, and mobile phase buffer concentration, pH, organic modifier and column temperature in the separation step. The method provides quantitative information on free and total cysteine based on assays with derivatization before and after reduction with tri-nbutylphosphine. The calibration graph, obtained with the use of normal urine spiked with growing amounts of cystine, was linear over the concentration range covering most experimental and clinical cases. The assay has a low pmol detection and quantitation limits, low imprecision and high recovery. The method was validated for urine samples received from several donors.

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Author

Edward Bald; Rafal Glowacki; Józef Drzewoski

Publisher

Elsevier Science; Elsevier ; Elsevier BV (ISSN 1873-3778)

Published

2001

Language

EN

Field

Chemistry (Physical Sciences)