Synthesis of magnetic MIL-53(Fe) as an efficient sorbent for coextraction and determination of acidic, basic and amphiprotic pollutants

Phenol, aniline and their derivatives are some of the most important pollutants present in the environment, have become more and more significant due to their high toxicity to natural environments and humans [1]. Owing to their high toxicity, it is crucial to develop a reliable, sensitive, and environmentally friendly method for determination of these pollutants. Nowadays different analytical techniques have been developed for the determination of these compounds by high-performance liquid chromatography (HPLC) [2]. Sample pretreatment and preconcentration step is always necessary prior to mentioned techniques for determination, due to the low concentration of these compounds in real samples [3].In this study, an easy and fast dispersive micro-solid phase extraction (D-μ-SPE) method was developed for coextraction of target analytes. Magnetic MIL-53(Fe) was synthesized and used as an efficient sorbent in D-μ-SPE method. The synthesis of MOF was confirmed by Fourier transform infrared spectroscopy, X-ray dispersive spectroscopy, thermogravimetry analysis, scanning electron microscopy, transition electron microscopy, vibrating sample magnetometry and X-ray diffraction. The method is easily operated, benefits from good reproducibility values, low detection limit with wide dynamic linear range, and acceptable extraction recovery. Due to the magnetic property, the phase separation was convenient and rapid for D-μ-SPE procedure.The opted conditions were: pH of the sample, 5; MOF amount, 20 mg; sorption time, 8 min; salt concentration, 15% w/v; sample volume, 20 mL; type and volume of the eluent, acetonitrile, 130 μL; elution time; 2 min. Under the optimum conditions detection limits and linear dynamic ranges were obtained in the range of 0.03-0.2 μg L−1 and 0.1-2000 μg L−1, respectively. The percent of extraction recovery and relative standard deviations (n = 5) were in the range of 39.5-93.34 and 3.5-12.6, respectively. Eventually, the synthesized magnetic MOF was successfully applied for the coextraction and determination of target analytes in various water samples with satisfactory results.