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Comparison of quantitative performance of three fluorescence labels in CE/LIF analysis of aspartate and glutamate in brain microdialysate
Author(s) -
Wagner Zsolt,
Tábi Tamás,
Zachar Gergely,
Csillag András,
Szökő Éva
Publication year - 2011
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201100032
Subject(s) - derivatization , chromatography , chemistry , analyte , fluorescence , quantitative analysis (chemistry) , detection limit , fluorescein , fluorescein isothiocyanate , amino acid , high performance liquid chromatography , biochemistry , physics , quantum mechanics
Three different fluorescent tags have been compared for the quantitative analysis of aspartate and glutamate in brain microdialysate samples. Separation conditions have been optimized to achieve short analysis time using reversed polarity separation in coated capillary. Method validation has revealed similar quantification limit of 0.1 μM of analytes using either of the labels, although LOD values were different: 7.8–9.8 nM for 4‐fluoro‐7‐nitro‐2,1,3‐benzoxadiazole, 3.5 nM for fluorescein‐5‐isothiocyanate and 1.3–1.5 nM for carboxyfluorescein succinimidyl ester derivatives. The almost two orders of magnitude difference between LOD and LOQ values is likely due to the unreliable derivatization reaction at low sample concentration. Based on the superior stability, FITC derivatization was used for the analysis of biological samples. The applicability of the method has been demonstrated by analyzing basal and potassium evoked amino acid concentrations in individual brain microdialysate samples.