A two-step microextraction method was performed for the extraction of trifluralin as a common herbicide in environmental water samples followed by continuous negative corona discharge ion mobility spectrometry (CD-IMS). At first, n-octyl-triethoxysilane surface-modified magnetic iron oxide nanoparticles (C8M) were synthesized. The DLLME was performed by injecting 1 mL of methanol (disperser) containing10µL of n-hexane (extraction solvent) into 10 mL of water sample. C8M were immediately added to this solution for the retrieval of the extraction solvent and the extracted trifluralin by sonication . Subsequently, a magnet was used to isolate the C8M. Then, the water sample was decanted, the nanoparticles were dried, and the trifluralin was extracted from nanoparticles by sonication with methanol. Variables affecting the performance of both steps were thoroughly optimized. Under the optimized conditions, analytical parameters such as linearity and limit of detection were obtained. Dynamic range 2-100ng/ml and a low detection limit 0.7ng/mL were obtained. The enrichment factor was 49. This method was applied for the determination of trifluralin in well water samples.
