Development of a novel IMAC sorbent for the identification of melamine in dairy products by HPLC

Abstract

To determine melamine (MEL) in dairy products, a novel immobilized metal affinity chromatography (IMAC) sorbent using chitosan (CTS) and 2-hydroxyethyl methacrylate (HEMA) as monomers, ethylene glycol dimethacrylate (EGDMA) as cross-linker and Cu2+ ions as chelated metal ion was synthesized by radical polymerization and characterized by Fourier transfer infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and swelling test. Adsorption parameters (pH, contact time, initial concentration, etc.) were studied to evaluate the adsorption process. The results showed that the CTS-p(HEMA)-Cu2+ IMAC sorbent displayed a rapid dynamic adsorption with a maximum adsorption capacity of 275.49 μg g−1 toward melamine. The CTS-p(HEMA)-Cu2+ IMAC sorbent was also applied to determine and enrich melamine in dairy products (milk and infant formula). An enrichment ratio of 5-fold, detection limit of 0.005 and 0.015 μg mL−1, and quantification limit of 0.0150 and 0.1261 μg mL−1 were achieved for MEL in milk and infant formula, respectively.