The determination of cysteamine in physiological fluids by HPLC with electrochemical detection

Abstract

Cysteamine, an amino thiol, was separated by rapid isocratic cation exchange chromatography and detected by electrochemical oxidation at a platinum electrode maintained at +0.45 V relative to an Ag/AgCl reference electrode. Eluent pH and electrode working potentials were optimized and the effects of alternative buffers and organic modifiers have been examined. On column sensitivity for cysteamine was 1.5 pmol at a signal-to-noise ratio of 5. Although the specificity was good, plasma samples required maximal sensitivity whereas urine samples required greater selectivity, which was achieved by use of lower working potentials. Cysteamine concentrations were determined in serial samples of plasma and urine from volunteers who had received a single oral dose of 200 mg of the drug. Cysteamine was rapidly oxidized in vivo, and detection required prior reduction with dithiothreitol before analysis.

Measurement of reduced and total mercaptamine in urine using liquid chromatography with ultraviolet detection

“…However, in accordance with our knowledge, only four works offer procedures for the determination of total mercaptamine in human urine (Kelly et al, 1987;Kataoka et al, 1994;Pastore et al, 1998;Lochman et al, 2003). These methods take advantage of sometimes sophisticated, less commonly used techniques such as gas chromatography with flame photometric detection (Kataoka et al, 1994), capillary electrophoresis with laser-induced fluorescence or liquid chromatography with electrochemical (Kelly et al, 1987) and fluorescent detection (Pastore et al, 1998). Furthermore, so far, the chemical literature has not described the procedure for determination of different redox forms of mercaptamine.…”

“…Mercaptamine has been measured directly, without chemical modification, by liquid chromatography with electrochemical detection (Kelly et al, 1987;Smolin and Schneider, 1988). Nevertheless the majority of analytical procedures for mercaptamine have involved some form of derivatization.…”

Determination of endogenous thiols and thiol drugs in urine by HPLC with ultraviolet detection

“…In accordance with our knowledge, only five works offer procedures for the determination of cysteamine in human urine [32,38,59,60,61], however, only one takes advantage of an HPLC-UV technique [61]. This method is based on derivatization of cysteamine with CMQT followed by ion-pairing reversed-phase liquid chromatography separation and ultraviolet-absorbance detection at 355 nm.…”

Recent advances in separation and detection methods for thiol compounds in biological samples

“…It is also widely used as a drug for the treatment of nephropathic cystinosis, a rare autosomal recessive disease characterized by poor growth, renal Fanconi syndrome and renal glomerular failure [39,40]. The determination of cysteamine has been directly carried out, without chemical modification, by LC with ECD [41,42]. However, the majority of the analyses involved the derivatization process with some FL tagging reagents [43,44].…”