Surfactant-assisted electromembrane extraction combined with capillary electrophoresis as a novel technique for the determination of acidic drugs in biological fluids.

In this paper, for the first time, surfactant-assisted electromembrane extraction coupled with capillary electrophoresis with UV detector was introduced for the extraction of acidic drugs from biological fluids. In this technique, in the presence of the nonionic surfactant in the donor phase, tendency of analyte ions into the supported liquid membrane (SLM) was increased. Naproxen and diclofenac were selected as model acidic drugs. In order to obtain the best extraction efficiency, several factors influencing the extraction efficiency were investigated. Optimal extractions were accomplished with 1-octanol as the SLM, 15 Volt dc potential as the driving force, pH 12 in acceptor solution, and 0.2 mmol/L Triton X-100 with pH 7.4 in donor solution. Equilibrium extraction conditions were obtained after 15 min of operation where the whole assembly agitated at 1000 rpm. Under the optimized conditions, preconcentration factors in the range of 176-184 and recoveries in the range of 88-92% were obtained. The applied method offers acceptable linearity with correlation coefficients higher than 0.9992. Limits of detection of 1.51 ng/mL and 2.42 ng/mL were obtained for naproxen and diclofenac, respectively. Finally, the developed method was successfully applied for the determination of naproxen and diclofenac in different matrices including plasma and urine samples.