For the first time, solvent bar microextraction using a reverse micelle RMM-SBME as extraction phasewas developed for extraction of warfarin in human plasma sample. The reverse micelle of a cationic sur-factant (hexadecyltrimethylammonium bromide) in 1-octanol was applied as supported and acceptorphase in SBME. In this process, the analyte was extracted from aqueous samples into a reverse micelleimpregnated and also filled in the wall pores and lumen the polypropylene hollow fiber membrane bythe electrostatic interactions between the analyte and the surfactant head groups. The influences of fun-damental parameters affecting extraction efficiency of warfarin including sample solution pH, surfactantconcentration and extraction time were studied using central composite design optimization method.The analysis of extracted analyte was performed by high performance liquid chromatography with ultraviolet detector.Under the optimum condition, the sample containing 40 ng mL−1of warfarin was extracted with extrac-tion recovery of 97.8% that pertained to enrichment factor of 260. A good linearity over a concentrationrange 1–600 ng mL−1with correlation coefficient value of 0.9989 was provided by the current method.Limits of detection and inner and inter-day relative standard deviation were 0.3 ng mL−1and less than4.4%, respectively. This method was compared to conventional SBME, and illustrated higher extractionefficiency. The method needs minimal sample preparation time since the porous hollow fiber membraneprevents from being extracted potential interfering materials, acts as a filter, and any extra cleanup wasnot required. The method with bar of 3 cm and acceptor phase volume of 8.5 L is environmentallygreen/friendly method. The proposed method was successfully applied for the preconcentration anddetermination of warfarin in plasma sample.
