High‐throughput capillary electrophoretic method for determination of total aminothiols in plasma and urine

Abstract

Increased interest in the analysis of aminothiols in body fluids during the last years results in a request for high-throughput analytical methods for their determination. We report here a novel, high-throughput method for the determination of total concentrations of biogenous aminothiols - homocysteine, cysteine, glutathione, cysteinylglycine, gamma-glutamylcysteine, and of penicilamine, mercaptopropionylglycine, and cysteamine, three compounds used to treat disorders of aminothiol metabolism in plasma and urine. Samples were reduced with tris(carboxyethyl)phosphine and labeled with 5-(bromomethyl)fluorescein. Capillary electrophoretic separations were performed in 60 mmol/L borate - 15 mmol/L sodium dodecyl sulfate - 2-amino-2-methyl-1-propanol, pH 10.0, with laser-induced fluorescence detection. Analysis time was less than 2 min. The assay is linear (r > 0.999) up to 500 micromol/L. Reproducibilities of migration times (coefficient of variation, CV) were < 0.5%. Interassay repeatabilities (CV, n = 10) were 5.08% and 6.09% for 5 micromol/L addition of homocysteine and 0.60% and 3.78% for 100 micromol/L addition of cysteine in plasma and urine, respectively. Recovery values were within 94-106% and sensitivity was better than 0.19 micromol/L for all analyzed compounds. Results agreed well with a standard high-performance liquid chromatography (HPLC) method. The diagnostic usefulness of the method has been proven on 79 samples of cystinuric patients and 12 samples of homocystinuric patients. We report here a novel method for the determination of aminothiols in body fluids by capillary electrophoresis (CE). Determination is fast and sensitive enough for diagnostic purposes.

Electrocatalytic determination of cysteamine using multiwall carbon nanotube paste electrode in the presence of 3,4-dihydroxycinnamic acid as a homogeneous mediator

“…4 Cysteamine and its disulfide, cystamine, have been shown to be neuroprotective in a number of cell culture and animal models. 5 With this goal in mind, a rapid but specific and sufficiently sensitive analytical method was required for total cysteamine determination in biological and pharmaceutical samples. Numerous methods have been reported for the determination of CA in pharmaceutical and biological samples including chromatography, [6][7][8] electrophoresis, 9 gas chromatography with flame photometric detection, 10 ion exchange chromatography, 11 and electrochemical methods [12][13][14] using modified electrodes.…”

Redox status expressed as GSH:GSSG ratio as a marker for oxidative stress in paediatric tumour patients

“…It is a tripeptide composed of cysteine, glutamic acid and glycine. Intracellular and whole blood concentrations of GSH are in the milimolar range, while the plasma concentration is in the micromolar range and accounts for approximately 0.4% of total blood GSH (1)(2)(3)(4)(5). The GSH synthesis and metabolism pathway is shown in Fig.…”

Simultaneous Determination of Glutathione and Glutathione Disulfide in an Acid Extract of Plant Shoot and Root by Capillary Electrophoresis

“…Studies where time is below this range are less frequent. In this respect, both Carru et al 12 and Lochman et al 31 report times below 2 min for simultaneous analysis of reduced and oxidized glutathione analysis, using a BGE constituted by borate and 20-and 30-cm capillaries. However, they provide little information concerning electrophoresis conditions used and generated current.…”