Optimized Preconcentration Method Using Ionic Liquid Ferrofluid for Ultra-Trace Determination of Cr(VI) in Drinking Water by Inductively Coupled Plasma Mass Spectrometry

Herein, a simple and fast method was developed for efficient preconcentration of anionic Cr(VI) in drinking water using, for the first time, an ionic liquid ferrofluid (IL-FF) for its interference-free ultra-trace (ng L -1 ) determination by inductively coupled plasma mass spectrometry.To improve the selectivity of the IL-FF, the surface of commercially available Fe3O4 magnetic nanoparticles (MNPs) was coated with silica and functionalized with L-cysteine (SCMNPs-Cys).The structural features of the SCMNPs-Cys were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, and X-ray diffraction.Experimental conditions, including the sample solution pH, elution time, and eluent concentration, were optimized.A 20-fold enrichment factor resulted in a limit of detection of 3 ng L -1 .The applicability of the method was confirmed by the analysis of Cr(VI) in different water samples with recoveries of 84-91% (n=3).