Analytical Sciences

Abstract − Analytical Sciences, 34(4), 505 (2018).

Determination of Blood Plasma Aminothiols Using Derivatization-enhanced Capillary Transient Isotachophoresis
Alexander V. IVANOV, Ksenya A. NIKIFOROVA, Polina O. BULGAKOVA, Edward D. VIRUS, and Aslan A. KUBATIEV
Department of Molecular and Cell Pathophysiology, Federal State Budgetary Scientific Institution “Institute of General Pathology and Pathophysiology”, Baltiyskaya St., 8, Moscow, 125315, Russia
A sensitive capillary electrophoresis method was developed for the determination of aminothiol (cysteine, homocysteine, and glutathione) total levels in human blood plasma. Analytes were derivatized with Ellman’s reagent (5,5′-dithiobis(2-nitrobenzoic acid)) after reduction with dithiothreitol. Liquid–liquid extraction was applied to purify the samples and concentrate the analytes. Total analysis time was 7.5 min using a silica capillary (50 μm i.d.; effective separation length 23.5 cm). Electrophoretic separation was performed using 50 mM citric acid with 20 mM triethanolamine (pH 3) containing 2% Ficoll 400. Detection limit was 0.8 μM for glutathione and 0.3 μM for both cysteine and homocysteine. Accuracy was 94 – 107%, repeatability and reproducibility were ca. 2.7 – 3.5 and 2.5 – 6.5%, respectively.