Magnetic solid-phase extraction of trace elements in water and fish using greenly synthesized MnFe2O4 @ cabbage hydrochar/chitosan ternary composite

A new analytical method for determining lead, cadmium, and copper in water and fish was established employing a novel synthesized magnetic eco-friendly ternary nano-composite adsorbent of manganese ferrite@cabbage hydrochar/chitosan (MnFe 2 O 4 @CBH/CTS). Cabbage leaves were employed as a green fuel, acting as a reducing and capping agent in the green manufacture of manganese-ferrite nanoparticles , and then hydrothermally carbonized to form hydrochar . The novel material underwent FT-IR, XRD , SEM, EDX , and BET investigation, revealing a micro-porous surface. The magnetic solid-phase extraction (MSPE) technique was used to enrich the samples and separate the matrix for GFAAS analysis. The impact of adsorption factors such as pH, extraction duration, metal ion concentration, and interference from coexisting ions were examined. Based on a preconcentration factor of 50, the method demonstrated LOD (3σ/m) ranging from 6 to 18 ng L −1 , linearity (ng L −1 ) from 48 to 450 (Pb), 20–180 (Cd) and 59–300 (Cu), and precision (RSD, n=3) of 1.8–3.9 % (1.0 μg L −1 ) and 3.0–4.6 % (10 μg L −1 ). The approach was effectively applied to the analysis of tested elements in water and marine fish samples, with spiked sample recoveries above 95 % and an RSD of less than 5.4 %. • Green synthesis of Ternary nanocomposite. • New magnetic adsorbent of Cabbage and Chitosan biomass materials. • Magnetic-SPE approach for Pb, Cd, and Cu preconcentration in water and fish. • The nanocomposite was an eco-friendly, highly durable, and easy-recovery biomaterial.