Determination of 2, 4-Dichlorophenol, 2, 4-Dinitrophenol, and Bisphenol a in River Water by Magnetic Solid-Phase Extraction (MSPE) Using beta-Cyclodextrin Modified Magnetic Ferrite Microspheres and High-Performance Liquid Chromatography - Diode Array Detection (HPLC-DAD)

beta-Cyclodextrin modified magnetic microspheres were synthesized and used as an effective adsorbent for the solid-phase extraction of three phenols from water samples. Scanning electron microscopy and Fourier transform infrared spectrometry were used to characterize the adsorbents. The major parameters affecting the extraction and desorption efficiencies, such as adsorbent dosage, extraction time, pH, ionic strength, and eluent type were systematically optimized. Under these conditions, three phenols in water samples were extracted and determined by high performance liquid chromatography (HPLC) with diode array detection (DAD). Limits of detection (LODs) of 0.04-0.34 ng mL(-1) and limits of quantification (LOQs) from 0.13 to 1.14 ng mL(-1) were achieved with good repeatability (relative standard deviation <7.5%). The developed method was applied for the determination of 2,4-dichlorophenol, 2,4-dinitrophenol and bisphenol A in spiked Yangtze River water, and the recoveries were from 81.0% to 94.9%. The results demonstrated that the combination of magnetic solid-phase extraction (MSPE) with HPLC-DAD is suitable for the determination of trace phenolics in environmental water.