A Highly Sensitive Dispersive Microextraction Method with Magnetic Carbon Nanocomposites Coupled with Dispersive Liquid-Liquid Microextraction and Two Miscible Stripping Solvents Followed by GC-MS for Quantification of 16 PAHs in Environmental Samples

In this work, a highly sensitive solid-phase-dispersive microextraction method was designed based on magnetic carbon nanocomposites as a magnetic solid-phase extraction sorbent coupled with dispersive liquid-liquid microextraction and two miscible stripping solvents (MSPE-DLLME) followed by gas chromatography-mass spectrometry (GC-MS) for determination of 16 polycyclic aromatic hydrocarbons (PAHs). By adopting this research methodology, a mixture of two miscible organic solvents is used not only as stripping solvent for MSPE, but also as extraction and disperser solvents for DLLME procedure. Several parameters such as amount of extraction adsorbent, type of stripping, extraction solvents and their volumes, salt effect, and pH and volume of sample solution were optimized to obtain high extraction recoveries. Finally, 2 A mu L of extraction phase was injected into GC-MS. Under optimal conditions, the method attained satisfactory precisions (RSD% ae 8.66), excellent limits of detection in the range of 0.1-0.5 ng kg(-1) at S/N = 3, and very high enrichment factors in the range of 28,187-33,149 for 500 mL sample solution of different PAHs. The calibration curves of 16 extracted PAHs were linear in the range of 0.4-10,000 ng kg(-1), with coefficients of determination (r (2)) between 0.9989 and 0.9999. The optimized method to determine 16 PAHs has been successfully applied in the real environment including waters, waste water, sewage, and soil.