Microwave-assisted synthesis of ionic liquid-modified silica as a sorbent for the solid-phase extraction of phenolic compounds from water

In this work, N-methylimidazolium ionic liquid-modified silica was synthesized using microwave irradiation. The modified silica was characterized by Fourier transform infrared analysis, elemental analysis, energy spectrum analysis, thermogravimetric analysis, and scanning electron microscopy. The synthesized material was used as a sorbent for the solid-phase extraction of four phenolic compounds from water. The extraction conditions including the type and consumption of eluent, the amount of sorbent, the pH, and the flow rate of the water samples were optimized. Satisfactory extraction recoveries were achieved using 200 mg of functionalized silica, 5 mL of methanol as eluent, a sample pH of 5, and a flow rate of 3 mL min(-1). The analytes were separated and detected using high-performance liquid chromatography. Analyte recoveries were found to be between 88% and 102% under optimized conditions with a relative standard deviation of <= 7%. The method was successfully applied for the extraction of phenolic compounds from water samples, indicating that ionic liquid-functionalized silica cartridges performed better than bare silica cartridges in the extraction of these analytes.