Bare polyprolylene hollow fiber as extractive phase for in-tube solid-phase microextraction to determine estrogens in water samples

Polypropylene hollow fibers as the adsorbent were directly filled into a polyetheretherketone tube for in-tube solid-phase microextraction. The surface properties of hollow fibers were characterized by a scanning electron microscope. Combined with high performance liquid chromatography, the extraction tube showed good extraction performance for five environmental estrogen hormones. To achieve high analytical sensitivity, four important factors containing sampling volume, sampling rate, content of organic solvent in sample, and desorption time were investigated. Under the optimum conditions, an online analysis method was established with wide linear range (0.0320 mu g/L), good correlation coefficients (>= 0.9998), low limits of detection (0.01-0.05 mu g/L), low limits of quantitation (0.03-0.16 mu g/L), and high enrichment factors (1087-2738). Relative standard deviations (n = 3) for intraday (<= 3.6%) and interday (<= 5.1%) tests proved the stable extraction performance of the material. Durability and chemical stability of the extraction tube were also investigated, relative standard deviations of all analytes were less than 5.8% (n = 3), demonstrating the satisfactory stability. Finally, the method was successfully applied to detect estrogens in real samples.