Effect of the combined use of γ-cyclodextrin and a chiral ionic liquid on the enantiomeric separation of homocysteine by capillary electrophoresis.

Autor: Greño M; Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá. Ctra, Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain., Marina ML; Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá. Ctra, Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain; Instituto de Investigación Química Andrés M. del Río, Universidad de Alcalá. Ctra, Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain., Castro-Puyana M; Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá. Ctra, Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain; Instituto de Investigación Química Andrés M. del Río, Universidad de Alcalá. Ctra, Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain. Electronic address: maria.castrop@uah.es.
Jazyk: angličtina
Zdroj: Journal of chromatography. A [J Chromatogr A] 2018 Sep 21; Vol. 1568, pp. 222-228. Date of Electronic Publication: 2018 Jul 05.
DOI: 10.1016/j.chroma.2018.07.023
Abstrakt: The enantioseparation of the non-protein amino acid homocysteine by CE was investigated in this article using eleven neutral CDs and five chiral ionic liquids as chiral selectors. Using a previous derivatization step with FMOC and the subsequent separation under neutral conditions, homocysteine enantiomers were only separated when γ-CD or (R)-N,N,N-trimethyl-2-aminobutanol-bis(trifluoromethane-sulfon)imidate (EtCholNTf 2 ) were employed as sole chiral selectors in the separation buffer. On the one hand, γ-CD gave rise to the enantiomeric separation in 10min with a resolution value of 1.9, whereas EtCholNTf 2 let to obtain a resolution value of 1.4 in more than 50min. Then, the evaluation of the combined use of both selectors was also carried out, resulting in a considerable increase in the Rs. The best enantioseparation for homocysteine was obtained when 10mM EtCholNTf 2 was added to 50mM phosphate buffer (pH 7.0) containing 2mM γ-CD. In an attempt to discriminate specific chiral cation effect from the salt effect, the influence of adding LiNTf 2 to the separation medium was also evaluated, resulting in lower resolution values for homocysteine when compared to those achieved with the addition of EtCholNTf 2 , indicating a synergistic effect between EtCholNTf 2 and γ-CD. Interestingly, the enantiomer migration order changed depending on the use of a single chiral selector or dual systems. When EtCholNTf 2 or γ-CD were employed as sole chiral selectors, D-enantiomer was the first-migrating enantiomer. However, an inversion in the migration order was observed when both selectors were combined in a dual system being the L-enantiomer the first-migrating one.
(Copyright © 2018 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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