Magnetic graphitic carbon nitride nanoparticles covalently modified with an ethylenediamine for dispersive solid-phase extraction of lead(II) and cadmium(II) prior to their quantitation by FAAS

A magnetic graphitic carbon nitride (g-C3N4-Sn-Fe2O4) modified with N-[3-(trimethoxysilyl) propyl] ethylenediamine (TPED) was synthesized and utilized as a nanoadsorbent for the ultrasound-assisted magnetic dispersive microsolid-phase extraction of the ions Pb(II) and Cd(II) from foodstuff. The presence of the TPED group on the nanoadsorbent results in a superior uptake of the analytes via complexation. The grafting of TPED on the adsorbent was corroborated by FT-IR, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy elemental analysis, and vibrating sample magnetometry. The adsorption and desorption steps were optimized via the central composite experimental design. Following desorption, the ions were quantified via micro-sampling atomic absorption spectrometry. Under optimized conditions, the limits of detection (LODs) are 0.6 and 0.1 mu g L (-1) for for Pb(II) and Cd(II), respectively, the linear dynamic ranges extend from 2.0 to 600.0 mu g L-1, and the relative standard deviations (for n = 5) are 3.6 and 4.6%. Notably, only 5.0 mg of the nanoadsorbent are needed, and it can be reused up to 5 times at extraction recoveries of >99%.