A Chlorella/ZnO/ZnFe 2 O 4 nanocomposite was synthesized and exploited for preconcentration of trace levels of heavy metals in foods, prior to measurement by ICP-OES. The synthesized nanocomposite showed outstanding properties such as high eco-degradability, cost-effectiveness, easy access to raw materials, high specific surface area, and efficient extraction recovery. It was utilized as an adsorbent in an ultrasonic-assisted D-μ-SPE procedure for preconcentration of Ni (II), Cu (II), Cd (II), Pb (II), and Hg (II) ions. Parameters were optimized and, under optimized conditions, the method attained detection limits ≤0.3 ng mL −1 , enrichment factors ≥52.14, linear ranges varied from 0.15 to 200 ng mL −1 for all analytes, and RSDs ≤3.1% ( n = 5). The proposed method was successfully implemented for determination of metal ions in a variety of food samples (13 different samples), including grains, vegetables, animal-derived products, and seafood, demonstrating high analytical applicability for trace metal monitoring in complex food systems. • Chlorella/ZnO/ZnFe 2 O 4 nanocomposite made for heavy metal preconcentration in food samples. • Nanocomposite achieved detection limits lesser than 0.3 ng mL −1 , with high recoveres. • Magnetic properties enabled fast, easy separation and reusability of sorbent. • Method works in complex food matrices including grains, vegetables, seafood. • Sustainable, eco-friendly UA-D-μ-SPE method validated by green metrics.
Qezelje et al. (Wed,) studied this question.