Alginate integrated sodium ferrite nanocomposite-based dispersive solid-phase extraction for trace detection of metal ions in water and juices

In this work sodium ferrite nanoparticles (Na₂Fe₄O₇-NPs) were synthesized through a sol-gel green synthesis process using an aqueous extract of tamarind fruit and then combined with sodium alginate to synthesize composite AG/Na₂Fe₄O₇-NC. The synthesized nanoparticles and the composite were characterized by advanced analytical techniques to study crystalline behaviour, morphology, surface charge, and size distribution. AG/Na₂Fe₄O₇-NC was employed to develop a novel dispersive solid-phase extraction (DSPE) method for the simultaneous detection of heavy metals (HMs), including Cd, Co, Cu, Mn, Ni, and Pb, by flame atomic absorption spectrometry. Various experimental factors, including pH, nanocomposite dose, sample volume, eluent composition, eluent concentration, and eluent volume, were examined to maximize efficiency. The developed AG/Na₂Fe₄O₇-NC based DSPE method showed limits of detection (LODs) of 0.6, 0.2, 4.9, 1.0, 6.0, and 0.1 ng L^-1 for Cd, Co, Cu, Mn, Ni, and Pb, respectively, with a preconcentration factor of 250. The accuracy of the method was validated using certified reference material (CRM), yielding excellent recovery rates between 97.1% and 98.7%. This developed method was successfully applied to measure HMs in tap water and fruit juice samples. The AG/Na₂Fe₄O₇-NC enhance the adsorption efficiency of the developed DSPE method and makes it a powerful tool for analyzing trace metals in environmental and food safety applications.