Carbon nanotubes/metal-organic framework based magnetic dispersive micro-solid phase extraction for the determination of triazole fungicides in wastewater and soil samples

Abstract

In this research, the magnetic dispersive micro solid phase extraction (M−D-µ-SPE) method was used for pre-concentration and trace detection of triazole fungicides in agricultural wastewater and soil samples. The nano sorbent used for M−D-µ-SPE is based on a magnetic carbon nanotubes/Cu-based MOF (M−MWCNT−Cu−BDC) nanocomposite, which was synthesized and characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, vibrating-sample magnetometer, and Nitrogen adsorption-desorption analysis. The effective parameters on the extraction performance were optimized, and under the optimized conditions (pH value: 7.0; the amount of sorbent: 30 mg; extraction time: 30 min; desorbing agent: ethanol; the volume of desorbing solvent: 500 μL and desorption time: 5 min), the limits of detection (LOD) was 0.45 ng mL−1, and the linear range was 1.50 to 750 ng mL−1 with a correlation coefficient higher than 0.993. The repeatability (RSD%) of the method for five replicates ranged from 2.8 to 5.5%. High recoveries (91–94%) and excellent preconcentration factor (PF = 91–94) were also obtained. Finally, this method was applied to determine triazole fungicides in agricultural wastewater and soil samples.