Article (Scientific journals)
Enantioselective capillary electrophoresis-mass spectrometry of amino acids in cerebrospinal fluid using a chiral derivatizing agent and volatile surfactant.
Prior, A.; Moldovan, Radu-Cristian; Crommen, Jacques et al.
2016In Analytica Chimica Acta, 940, p. 150-8
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Keywords :
Amino acids; Capillary electrophoresis-mass spectrometry; Cerebrospinal fluid; Chiral separation
Abstract :
[en] The sensitivity of coupled enantioselective capillary electrophoresis-mass spectrometry (CE-MS) of amino acids (AAs) is often hampered by the chiral selectors in the background electrolyte (BGE). A new method is presented in which the use of a chiral selector is circumvented by employing (+)-1-(9-fluorenyl)ethyl chloroformate (FLEC) as chiral AA derivatizing agent and ammonium perfluorooctanoate (APFO) as a volatile pseudostationary phase for separation of the formed diastereomers. Efficient AA derivatization with FLEC was completed within 10 min. Infusion experiments showed that the APFO concentration hardly affects the MS response of FLEC-AAs and presents significantly less ion suppression than equal concentrations of ammonium acetate. The effect of the pH and APFO concentration of the BGE and the capillary temperature were studied in order to achieve optimized enantioseparation. Optimization of CE-MS parameters, such as sheath-liquid composition and flow rate, ESI and MS settings was performed in order to prevent analyte fragmentation and achieve sensitive detection. Selective detection and quantification of 14 chiral proteinogenic AAs was achieved with chiral resolution between 1.2 and 8.6, and limits of detection ranging from 130 to 630 nM injected concentration. Aspartic acid and glutamic acid were detected, but not enantioseparated. The optimized method was applied to the analysis of chiral AAs in cerebrospinal fluid (CSF). Good linearity (R(2) > 0.99) and acceptable peak area and electrophoretic mobility repeatability (RSDs below 21% and 2.4%, respectively) were achieved for the chiral proteinogenic AAs, with sensitivity and chiral resolution mostly similar to obtained for standard solutions. Next to l-AAs, endogenous levels of d-serine and d-glutamine could be measured in CSF revealing enantiomeric ratios of 4.8%-8.0% and 0.34%-0.74%, respectively, and indicating the method's potential for the analysis of low concentrations of d-AAs in presence of abundant l-AAs.
Research center :
CIRM - Centre Interdisciplinaire de Recherche sur le Médicament - ULiège
Disciplines :
Pharmacy, pharmacology & toxicology
Author, co-author :
Prior, A.
Moldovan, Radu-Cristian 
Crommen, Jacques ;  Université de Liège > Département de pharmacie > Département de pharmacie
Servais, Anne-Catherine  ;  Université de Liège > Département de pharmacie > Analyse des médicaments
Fillet, Marianne ;  Université de Liège > Département de pharmacie > Analyse des médicaments
de Jong, G. J.
Somsen, G. W.
Language :
English
Title :
Enantioselective capillary electrophoresis-mass spectrometry of amino acids in cerebrospinal fluid using a chiral derivatizing agent and volatile surfactant.
Publication date :
2016
Journal title :
Analytica Chimica Acta
ISSN :
0003-2670
eISSN :
1873-4324
Publisher :
Elsevier, Netherlands
Volume :
940
Pages :
150-8
Peer reviewed :
Peer Reviewed verified by ORBi
Commentary :
Copyright (c) 2016 Elsevier B.V. All rights reserved.
Available on ORBi :
since 16 May 2017

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