Vortex-Assisted Magnetic Nanofluid-Based Liquid Phase Microextraction of Methylene Blue and Crystal Violet

In the present study, a new vortex-assisted magnetic solid phase extraction method was developed based on magnetic ZIF-67 (MZIF-67) nanofluid and supramolecular solvents (SUPRASs) for the extraction and preconcentration of synthetic dyes, followed by high performance liquid chromatography-diode array detector detection. MZIF-67 functionalized with sodium dodecyl sulfate and titanium dioxide (MZIF-67/SDS-TiO₂) were synthesized and used as magnetic materials. SUPRAS prepared from hexafluorobutanol and nerol was employed as the carrier liquid. Finally, FFs were prepared by adding MZIF-67/SDS-TiO₂ to SUPRAS for the first time. The prepared adsorbents were characterized by scanning electron microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The extraction efficiency of the developed method was enhanced by optimization of the influencing parameters. Under the optimized conditions, the linearity was in the range of 9-1000 ng mL^-1 with regression coefficients higher than 0.9961. The limits of detection and limits of quantification were in the range of 2.5-2.7-8.4-9.1 ng mL^-1, respectively. Finally, the developed method was applied to determine synthetic dyes in river water and beverage samples. Extraction recoveries ranged from 91.0% to 105.8% with relative standard deviations between 0.9% and 7.9%. The green character of the developed method was assessed using the AGREEprep tool. The obtained results indicate that the established method has low environmental impact. The developed method is a simple, cheap, green, and fast and can be applied to determine synthetic dyes in sample solutions.