Magnetic solid-phase extraction based on the Carbonized cotton fabric/zeolite imidazolate framework-71/Fe3O4/polythionine followed by atomic absorption spectrometry for cadmium monitoring in water, tomato and cabbage samples

Carbonized cotton fabric/zeolite imidazolate framework-71/Fe3O4/polythionine (CCF/ZIF-71/Fe3O4/PTh) was fabricated, characterized, and applied as efficient magnetic sorbent in magnetic solid-phase extraction (MSPE) of cadmium from water and food samples before determination by flame atomic absorption spectrometry (FAAS). This modification of carbonized cotton fabric led to making a great surface area and porosity, increase extraction efficiency, and acceptable selectivity. The characterization of this proposed sorbent was performed by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and Fourier transform-infrared (FT-IR) spectroscopy analysis techniques. The impact of several analytical parameters including pH, sorbent dosage, time of extraction, desorption condition, chelating agent concentration, the amount of salt and effect of potentially interfering ions on the selectivity and extraction recoveries of cadmium, were evaluated and optimized. In this proposed methodology, the limit of detection (LOD), the limit of quantification (LOQ), and relative standard deviation (RSD, n = 3) were found to be 0.21 ng mL−1, 0.6 ng mL−1 and lower than 3.0%, respectively. The validation and accuracy of the new advanced procedure were confirmed by applying the proposed procedure for certified reference materials (SRM1570A). Eventually, CCF/ZIF-71/Fe3O4/PTh can be utilized as a selective sorbent, for the rapid, accurate and sensitive determination of Cd (II)  in the samples.