Extraction and determination of trace amounts of three anticancer pharmaceuticals in urine by three-phase hollow fiber liquid-phase microextraction based on two immiscible organic solvents followed by high-performance liquid chromatography

An automated three-phase hollow fiber liquid-phase microextraction based on two immiscible organic solvents followed by high-performance liquid chromatography with UV-Vis detection method was applied for the extraction and determination of exemestane, letrozole, and paclitaxel in water and urine samples. n-Dodecane was selected as the supported liquid membrane and its polarity was justified by trioctylphosphine oxide. Acetonitrile was used as an organic acceptor phase with desirable immiscibility having n-dodecane. All the effective parameters of the microextraction procedure such as type of the organic acceptor phase, the supported liquid membrane composition, extraction time, pH of the donor phase, hollow fiber length, stirring rate, and ionic strength were evaluated and optimized separately by a one variable at-a-time method. Under the optimal conditions, the linear dynamic ranges were 1.8-200 (R-2 = 0.9991), 0.9-200 (R-2 = 0.9987) and 1.2-200 mu g/L (R-2 = 0.9983), and the limits of detection were 0.6, 0.3, and 0.4 mu g/L for exemestane, letrozole, and paclitaxel, respectively. To evaluate the capability of the proposed method in the analysis of biological samples, three different urinary samples were analyzed under the optimal conditions. The relative recoveries of the three pharmaceuticals were in the range of 91-107.3% for these three analytes.