Sodium nanoferrite-based solid phase extraction: a green method for the simultaneous determination of cadmium, copper, and lead†

In the current study, a solid phase extraction (SPE) methodology utilizing sodium ferrite nanoparticles (Na₂Fe₄O₇-NPs; SF-NPs) is presented for the simultaneous determination of heavy metals (HMs) via flame atomic absorption spectrometry (FAAS). SF-NPs were synthesized by an eco-friendly sol–gel auto-combustion method using Tamarindus indica fruit extract as a stabilizing agent. The characterized SF-NPs exhibited a high surface area with uniform distribution, high stability, and a negative surface charge, making it a promising material for excellent adsorption of HMs. The SF-NP-based SPE procedure involved optimizing parameters such as pH, adsorbent dosage, sample volume, eluent composition, volume, and concentration. The developed SF-NP-based SPE method demonstrated low detection limits, i.e., 0.006, 0.008, and 0.009 μg L⁻¹ for the analysis of Cd, Cu, and Pb, respectively. The SF-NP-based SPE methodology was validated by examining certified reference material and real samples, yielding accurate results with good recoveries (>95%) with a relative standard deviation of <5.0%. The developed SF-NP-based SPE method offers a promising approach for the simultaneous determination of Cd, Cu, and Pb in water and food samples, providing an efficient and environmentally friendly analytical tool for monitoring heavy metal contamination.