A Simple Vortex-Assisted Magnetic Dispersive Solid Phase Microextraction System for Preconcentration and Separation of Triazine Herbicides from Environmental Water and Vegetable Samples Using [Fe.sub.3][O.sub.4]@MIL-100 Sorbent

A vortex-assisted magnetic dispersive solid phase microextraction coupled with high-performance liquid chromatography has been developed for the extraction and determination of triazine herbicides by using magnetic metal organic frameworks [[Fe.sub.3][O.sub.4]@MIL-100(Fe)] in environmental water and vegetable samples. The [Fe.sub.3][O.sub.4]@MIL-100(Fe) composite has been characterized by using X-ray diffraction spectroscopy, tunneling electron microscopy, thermogravimetric measurement, and Brunauer-Emmett-Teller analysis. The method is based on the sorption of triazine herbicides on [Fe.sub.3][O.sub.4]@MIL-100(Fe) because of the complex formation between iron oxide nanoparticles and triazine herbicides beside [pi]-[pi] interactions between organic parts of [Fe.sub.3][O.sub.4]@MIL-100(Fe) and triazine herbicides. The experimental parameters for the preconcentration of triazine herbicides, such as the type and volume of the eluent, pH, time of the sorption and desorption, and the amount of the sorbent, were optimized. Under the optimized conditions, the method was linear over the concentration range of 0.0061 to 70 ng/mL for each triazine herbicide, and the correlation coefficients ranged from 0.9988 to 0.9997. The limit of detection of the method at a signal-to-noise ratio of 3 was 2.0 to 5.3 ng/mL. The relative standard deviations for inter- and intraday assays were in the range of 5.8 to 10.2% and 3.8 to 6.3%, respectively.