A new method for the enhancement of electromembrane extraction efficiency using carbon nanotube reinforced hollow fiber for the determination of acidic drugs in spiked plasma, urine, breast milk and wastewater samples.

A new design of low voltage electromembrane extraction (EME) using carbon nanotube reinforced hollow fiber was developed for the determination of acidic drugs in biological and wastewater samples. The supported liquid membrane (SLM) with carbon nanotubes as the sorbent interface was used in this research. CNTs have large surface area and high adsorption capacity for a wide range of organic and inorganic species. Therefore, the presence of CNTs in SLM increased the overall analyte partition coefficient in the membrane and lead to enhancement in analyte transport. Optimization of the variables affecting this method was carried out in order to achieve the best extraction efficiency. Ibuprofen and naproxen, nonsteroid anti-inflammatory drugs (NSAIDs), were selected as model acidic drugs. Optimal extractions were accomplished with 1-octanol with 3.0 mg mL(-1) CNTs as the SLM, with 5V as the driving force, and with pH 7.4 in donor and pH 12 in acceptor solutions. Equilibrium extraction conditions were obtained after 10 min of operation with the whole assembly agitated at 500 rpm. Under the optimized extraction conditions, the proposed EME technique provided good linearity (>0.998), repeatability (RSD=2.7-3.2), low limits of detection (1-3 ng mL(-1)), excellent preconcentration (PF=180-188) and high recoveries (90-94%). In comparison with the conventional EME method, this method showed better results (lower voltage, higher preconcentration factors and higher recoveries). Finally, the developed method was successfully used for the determination of ibuprofen and naproxen in different spiked matrices including plasma, urine, breast milk and wastewater samples.