Electromembrane extraction of phenytoin from biological fluids: A survey on the effects of molecularly imprinted polymer and carbon nanotubes on extraction efficiency

In the present study, an electrically-assisted microextraction method termed electromembrane extraction (EME) followed by a simple high performance liquid chromatography-ultraviolet detection was developed and validated for the determination of phenytoin in human biological samples. Main parameters influencing the electromembrane extraction were evaluated and optimized using the Box-Behnken experimental design. The membrane consisted of 1-octanol immobilized in the pores of a hollow fiber. As a driving force, a 40 V electric field was applied to facilitate the migration of analytes from the sample solution to an acceptor solution through a supported liquid membrane. The optimum donor and acceptor solutions pHs were achieved 10 and 13, respectively. The enrichment factor was > 82 within 15 min led to 55% absolute extraction recovery. In optimum conditions, the method provided the linearity in the range of 10-1000 ng/mL (R-2 > 0.999). The repeatability of the method was indicated as relative standard deviations (%RSD) between 3.6% and 8.9% (n = 3). The limits of detection and quantitation were 3.0 and 10.0 ng/mL, respectively. The sensitivity of HPLC-UV for determining phenytoin was enhanced by electromembrane extraction. Also, in this study, the effects of some nano-sorbents like carbon nanotubes and molecularly imprinted polymer on membrane performance and EME efficiency were evaluated. The EME technique can be introduced as a new approach for screening of molecularly imprinted polymers in their primary steps of characterization. Finally, the proposed EME-HPLC-UV method was applied for phenytoin determination in human plasma and urine samples with relative recoveries ranged between 88-92% indicating the reliability of the method.