Analysis of basic drugs in biological samples using dynamic single-interface hollow fiber liquid-phase microextraction combined with fast electromembrane extraction

In this study, a combination of single-interface hollow fiber liquid-phase microextraction and electromembrane extraction was applied for the extraction of some basic drugs from biological samples. The extraction process was followed by the HPLC-UV instrument. In this dynamic system, 1-octanol was impregnated into the pores of hollow fiber wall as an acceptor phase, the sample solution (pH = 12.0) was pumped into the lumen of hollow fiber by a syringe pump, the extraction efficiency was improved by filling and emptying (25 times) of sample solution (step-1). The extracted analytes in the organic acceptor phase were back-extracted by a fast electromembrane extraction procedure (step-2). Effective parameters on the extraction efficiency of both methods were investigated and optimized. Under optimized conditions (organic acceptor phase: 1-octanol, sample solution volume: 1500 mu L, flow rate: 2.0 mL min(-1), the number of filling and emptying cycles: 25, voltage: 100 V, back-extraction time: 2 min, and aqueous acceptor phase: 100 mM HCl), the proposed method provided good linearity with determination coefficients ranging from 0.992 to 0.996 over a concentration range of 2.5-1000 ng mL(-)(1). Extraction recoveries were obtained in the range of 65.1 and 88.8%, which resulted in preconcentration factors in the range of 32.6-44.4. The limits of detection were found to be within the range of 0.12-0.36 ng mL(-)(1), while the corresponding repeatability ranged from 3.7 to 9.3% (n = 3). Finally, the optimized method was applied for the quantification of propranolol, diltiazem and, lidocaine in urine and, plasma samples with relative recoveries ranged between 94.1 and 105.4%, indicating the reliability of the method.