Modified ?-QuEChERS coupled to diethyl carbonate-based liquid microextraction for PAHs determination in coffee, tea, and water prior to GC?MS analysis: An insight to reducing the impact of caffeine on the GC?MS measurement

摘要

A fast, sensitive and eco-friendly method was developed for the determination of fifteen polycyclic aromatic hydrocarbons (PAHs) in different environmental matrices through gas chromatography mass spectrometry (GC?MS). The method utilizes a modified and miniaturized quick easy cheap effective rugged and safe (QuEChERS) clean up procedure coupled to an air-assisted dispersive liquid?liquid microextraction (AA-DLLME) for the enrichment of the concerned compounds. The AA-DLLME uses diethyl carbonate (DEC) as a green biobased solvent for the microextraction. DEC is considered as biodegradable (with octanol/water coefficient 3, resulting in low potential of bioaccumulation), classified as a green solvent and considered as one of the recommended solvent alternatives based on SSG results. The AA-DLLME procedure was optimized by One-Variableat-A-Time (OVAT) succeeded by experimental design applying Central Composite Face-centered (CCF) design. The method linear calibration was found in the range of 10?120 ?g/Kg for Benzo[a]pyrene and 5?100 ?g/Kg for all other PAHs with low detection limits ranging from 0.01 to 2.10 ?g/Kg. It could enrich the PAHs up to 166folds. The combination of modified ?-QuEChERS with the green AA-DLLME could sharply decrease the caffeine amount on the final extract injected to the GC?MS instrument. The method was successfully applied to coffee, tea, and water samples with acceptable % recovery ( 90%). Finally, the impact of our procedure to the environment from green analytical chemistry view was assessed by a novel metric system called AGREE, proving the greenness of our procedure.