Vortex-assisted magnetic solid-phase extraction of cadmium in food, medicinal herb, and water samples using silica-coated thiol-functionalized magnetic multiwalled carbon nanotubes as adsorbent.

The current work focuses on the facile and effective synthesis of a new nanocomposite based on multiwalled carbon nanotubes (MWCNT) decorated with magnetic core-shell Fe3O4@SiO2 and functionalized with 3-mercaptopropyltrimethoxysilane (3-MPTS) used in the vortex-assisted dispersive magnetic solid-phase extraction (VA-DMSPE) of Cd(II) ions in environmental and food samples. The nanocomposite was characterized and the parameters that influenced the VA-DMSPE were optimized through a fractional factorial design 25-1. The proposed method provided a preconcentration factor of 33.14 times, detection and quantification limits of 0.090 μg L-1 and 0.302 μg L-1, respectively, and a linearity range of 0.001-40.0 μg L-1. The developed method was effectively applied to preconcentrate and determine Cd(II) in water, tobacco, green tea leaves, ginkgo biloba, carrots, and rice samples, and its accuracy was evaluated using GF AAS.