Evaluation of three-phase hollow fiber microextraction based on two immiscible solvents coupled to GC and HPLC for determination of statin drugs in biological fluids

In this study, for the first time, extraction of three statin drugs from biological fluids using hollow fiber liquid phase microextraction based on two immiscible organic solvents prior to high performance liquid chromatography (HPLC) with diode array detection and gas chromatography (GC) with a flame ionization detector was investigated experimentally and theoretically. Three major statin drugs: atorvastatin, lovastatin, and simvastatin, were first extracted from a sample solution, into a thin layer of organic solvent (5% trioctylphosphine oxide in n-dodecane) present in the pores of a porous hollow fiber, and further into a mu L volume of organic acceptor (alkaline methanol) located inside the lumen of the hollow fiber. A systematic investigation of the proposed method was applied to find the optimal extraction conditions and to evaluate the interaction effects between the factors by designing experiments using central composite design. Under the optimized conditions, this technique gave a preconcentration factor in the range of 466 to 863 and 550 to 880 for HPLC and GC analysis, respectively. Good precision values (with relative standard deviations <= 12.1%) were obtained. Detection limits were in the range of 0.2-3 mu g L-1 and 0.2-5 mu g L-1 for the water and biological samples analysed using HPLC and GC, respectively. Also, quantification limits were in the range of 0.5-5 mu g L-1 and 1-10 mu g L-1 in water and biological samples, for HPLC and GC, respectively. Extraction recoveries of the drugs in water, urine, and plasma samples were obtained in the range of 64.7-110.0% and 61.2-104.4% by HPLC and GC, respectively. Compared to the traditional methods, the proposed method exhibits high clean-up with a suitable sensitivity and high preconcentration factors as well as good precision.