Micro-Solid Phase Extraction of Volatile Organic Compounds in Water Samples Using Porous Membrane-Protected Melamine-Modified MIL-88 Followed by Gas Chromatography-Mass Spectrometry

Abstract

Melamine-modified MIL-88 was synthesized through the solvothermal method and utilized as the extracting device for the µ-solid phase extraction (µ-SPE) of selected volatile organic compounds (VOCs) including benzene, toluene, ethylbenzene, and isomers of xylene (BTEXs) from different environmental water samples. The prepared melamine-MIL-88 (Fe) was enclosed inside the porous hydrophilic tea bag filter membrane. The sealed membrane containing the sorbent (15 mg) was used as the µ-SPE device. The quantification of the extracted BTEXs was done by gas chromatography-mass spectrometry (GC-MS) instrument. The prepared sorbent was confirmed by different characterizations including powdered X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformed infrared (FT-IR) spectroscopy. The method provided linearity range of 0.5–500.0 µg L−1 (depending on target analytes) and coefficients of determination (R 2) with the range of 0.9891–0.9981 under the optimum condition. The enrichment factors (EFs) were found to be between 39.0 and 48.0. The limits of detection (LODs) were also calculated to be between 0.08 and 0.42 µg L−1, while the range of corresponding absolute recoveries was in the range of 78–96%. The method relative standard deviations (RSDs) ranged from 5.5 to 11.8% (at 5.0 µg L−1). Moreover, the prepared melamine-MIL-88 (Fe) showed high adsorption capacity (130 mg g−1). The method is cost-effective, user-friendly, and with minimal consumption of organic solvent. In addition, melamine-MIL-88 has not yet been synthesized and investigated in the microextraction of the pollutants.