Ionic liquid-based carbon nanotube coated magnetic nanoparticles as adsorbent for the magnetic solid phase extraction of triazole fungicides from environmental water†
Ionic liquid-based magnetic carbon nanotubes (IL-Fe3O4@MWCNTs) were synthesized as a novel adsorbent for magnetic solid-phase extraction (MSPE) for the determination of six triazole fungicides, i.e. penconazole (Pen), tebuconazole (TEB), epoxiconazole (Epo), bitertanol (Bit), fenbuconazole (Fen) and difenoconazole (Dif), from aqueous solution by gas chromatography coupled to mass spectrometry. Scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD) and Energy Dispersive X-ray (EDX) spectrometry were used to characterize the adsorbent. Some important factors governing the extraction efficiency such as adsorbent type, dilution conditions, adsorbent amount, extraction time, desorption time and ionic strength were investigated and optimized. Under the optimal conditions, the enrichment factors of the method for the analytes were in the range of 125 to 1242. A good linearity was observed in the range of 0.5–50 ng mL−1 for Epo, Bit, Fen, and Dif, 1–50 ng mL−1 for Teb and 2–50 ng mL−1 for Pen, respectively, with the correlation coefficients ranging from 0.9968 to 0.9999. The limits of detection (LODs) and the limits of quantification (LOQs) of the method were within the range 0.05–0.22 ng mL−1 and 0.23–0.75 ng mL−1, respectively. The southern end of the Beijing-Hangzhou Grand Canal water (Hangzhou, China) was used to verify the applicability of the developed method for the determination of the targets.