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Application of surfactant assisted dispersive liquid–liquid microextraction as an efficient sample treatment technique for preconcentration and trace detection of zonisamide and carbamazepine in urine and plasma samples

Behbahani, Mohammad, Najafi, Fatemeh, Bagheri, Saman, Bojdi, Majid Kalate, Salarian, Mani, Bagheri, Akbar
Journal of chromatography 2013 v.1308 pp. 25-31
cationic surfactants, centrifugation, drugs, high performance liquid chromatography, ionic strength, liquid-phase microextraction, solvents, urine
A simple, rapid, and efficient method, based on surfactant assisted dispersive liquid–liquid microextraction (SA-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for simultaneous preconcentration and trace detection of zonisamide and carbamazepine in biological samples. A conventional cationic surfactant called cethyltrimethyl ammonium bromide (CTAB) was used as a disperser agent in the proposed approach. 1.5mL of CTAB (0.45mmolL⁻¹) (disperser solvent) containing 50.0μL of 1-octanol (extraction solvent) was injected rapidly into the 7.0mL of water or diluted plasma or urine. A cloudy solution (water, 1-octanol, and CTAB) was formed in the test tube. After formation of cloudy solution, the mixture was centrifuged and 20μL of collected phase was injected into HPLC for subsequent analysis. Some parameters such as the type and volume of the extraction solvent, the type and concentration of surfactant, pH, ionic strength and centrifugation time were evaluated and optimized. Under optimum extraction conditions, the limits of detections (LODs) were 2.1 and 1.5μgL⁻¹ (based on 3Sb/m) for urine samples, and 2.3 and 1.6μgL⁻¹ for plasma samples. Linear dynamic range of 5–300 and 5–200μgL⁻¹ were obtained for zonisamide and carbamazepine in all samples. Finally, the applicability of the proposed method was evaluated by extraction and determination of the drugs in urine and plasma samples.