Electromembrane extraction combined with cyclodextrin‐modified capillary electrophoresis for the quantification of trimipramine enantiomers

Abstract

A sensitive, simple and reproducible method was developed for preconcentration and determination of trimipramine (TPM) enantiomers in biological samples using electromembrane extraction combined with cyclodextrin-modified capillary electrophoresis (CE). During the extraction, TPM enantiomers migrated from a 5 mL sample solution through a thin layer of 2-nitrophenyl octyl ether NPOE immobilized in the pores of a hollow fiber, and into a 20 μL acidic aqueous acceptor phase presented inside the lumen of the fiber. A Box-Behnken design and the response surface methodology (RSM) were used for the optimization of different variables on extraction efficiency. Optimized extraction conditions were: NPOE as supported liquid membrane, inter-electrode distance of 5 mm, stirring rate of 1000 rpm, 51 V potential difference, 34 min as the extraction time, acceptor phase pH 1.0 and donor phase pH 4.5. Then, the extract was analyzed using optimized cyclodextrin (CD)-modified CE method for the separation of TPM enantiomers. Best results were achieved using 100 mM phosphate running buffer (pH 2.0) containing 10 mM α-CD as the chiral selector, applied voltage of 18 kV and 20°C. The range of quantitation for both enantiomers was 20-500 ng/mL. The method was very reproducible so that intra- and interday RSDs (n=6) were <6%. The limits of quantitation and detection for both enantiomers were 20 and 7 ng/mL, respectively. Finally, this method was successfully applied to determine the concentration of TPM enantiomers in plasma and urine samples without any pre-treatment.

Electrically-enhanced microextraction combined with maltodextrin-modified capillary electrophoresis for quantification of tolterodine enantiomers in biological samples

“…High enrichment factors for two enantiomers were obtained when NPOE was used as SLM. This result has also been observed in our previous works [50,56].…”

“…Thus, the applied voltage across a SLM is an important factor for efficient extraction of TOL enantiomers in EME. Based on our study, voltage and time are two parameters that act in parallel ways and their interactions should be considered in EME optimization [50]. The RSM (Fig.…”

Mass transfer in electromembrane extraction—The link between theory and experiments

“…This has partly been supported by experimental work. Thus, a large number of publications have investigated the effect of salt in the sample, and in most cases extraction recoveries have decreased with increasing content of salt in the sample for both basic and acidic analytes . However, the effect of salt has been found to be analyte dependent.…”

Application of pH-sensitive magnetic nanoparticles microgel as a sorbent for the preconcentration of phenoxy acid herbicides in water samples

“…On the other hand, HPLC has long run times and consumes very hazardous and expensive organic solvents in comparison with CE. Consequently, CE has many advantages compared to other chromatographic methods, such as high separation efficiency, short analysis time, low cost, good selectivity as well as low consumption of sample and solvent [23,24]. However, lower concentration sensitivity of CE with on-column UV detection, due to low sample injection volume and short optical path-length,…”