Analysis of methotrexate and its eight metabolites in cerebrospinal fluid by solid-phase extraction and triple-stacking capillary electrophoresis

We establish a triple-stacking capillary electrophoresis (CE) separation method to monitor methotrexate (MTX) and its eight metabolites in cerebrospinal fluid (CSF). Three stacking methods with different mechanisms were combined and incorporated into CE separation. Complete stacking and sharp peaks...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Analytical and bioanalytical chemistry 2010-11, Vol.398 (5), p.2183-2190
Hauptverfasser: Cheng, Hui-Ling, Chiou, Shyh-Shin, Liao, Yu-Mei, Lu, Chi-Yu, Chen, Yen-Ling, Wu, Shou-Mei
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:We establish a triple-stacking capillary electrophoresis (CE) separation method to monitor methotrexate (MTX) and its eight metabolites in cerebrospinal fluid (CSF). Three stacking methods with different mechanisms were combined and incorporated into CE separation. Complete stacking and sharp peaks were achieved. Firstly, the optimized buffer (60 mM phosphate containing 15% THF and 100 mM SDS) was filled into the capillary, which was followed by the higher conductivity buffer (100 mM phosphate, 2 psi for 45 s). The analytes extracted from CSF were injected at 2 psi for 99.9 s, which provided long sample zones and pH junction for focusing. Finally, the stacking step was performed by sweeping, and separation was achieved by micellar electrokinetic chromatography. The results of the linear regression equations indicated high linearity (r ≥ 0.9981) over the range of 0.5-7 μM. In intra- and inter-batch results, all data of RSD and RE were below 11%, indicating good precision and accuracy of this method. The LODs (S/N = 3) were 0.1 μM for MTX, 7-hydroxymethotrexate (7-OHMTX) and MTX-polyglutamates (MTX-(Glu) n, n ₌ ₂₋₅), 0.2 μM for MTX-(Glu)₆, and 0.3 μM for 2,4-diamino-N ¹⁰-methylpteroic acid (DAMPA) and MTX-(Glu)₇. Our method was implemented for analysis of MTX and its metabolites in the CSF, and could be used for evaluation of its curative effects of acute lymphoblastic leukemia patients. The data were also confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The results showed good coincidence. [graphic removed]
ISSN:1618-2642
1618-2650
DOI:10.1007/s00216-010-4152-3