Trace determination of Cu(II) in milk samples after preconcentration on Fe₃O₄@graphene oxide composite based imprinted polymer

Abstract

A new tailor‐fitted graphene oxide‐vinyl pyridine ion‐imprinted polymer (mGOVP/IIP), was synthesized using ethylene glycol dimethacrylate as a cross‐linking agent and 2,2′‐azo‐bis‐isobutyronitrile as an initiator to develop dispersive magnetic‐solid‐phase extraction method for the preconcentration of Cu(II) prior to the determination by flame atomic absorption spectrometry. The material was characterized and optimized for various parameters by batch mode, which includes the effect of initial concentration, contact time, temperature, and eluents. Herein, IIP demonstrated a high sorption capacity (63.54 mg g−1) at pH 5.6, with fast kinetics (15 min). The heterogeneity and chemisorption, mechanistic interpretation was explained by the Freundlich isotherm, pseudo‐second‐order kinetic model, respectively. Moreover, the higher selectivity coefficients for Cu(II) in the binary mixturess of concomitant ions signified preferential affinity over similar structural analogues. Additionally, it can be regenerated up to 7 runs and effectively eluted by 1 M HNO3. This developed method exhibited higher accuracy, precision (relative standard deviation <5%), and preconcentration factor (60). The IIP also described potential applications for Cu(II) determination in milk and its by‐products. Overall, the material exhibits ease of access and removal of template ion from the binding sites, cost‐effectiveness, fast mass transfer, promoted competitiveness, reproducibility, reliability, and good regeneration efficiency.