Extraction of melamine from milk using a magnetic molecularly imprinted polymer

A novel magnetic molecularly imprinted polymer (MMIP) for the preconcentration of melamine, a non-protein nitrogen food additive from complex matrices was synthesized and characterized using FT-IR, XRD, SEM and VSM techniques. Surface imprinting was done on vinyltrimethoxysilane coated Fe₃O₄ (Fe₃O₄-VTMS) using 2-acrylamido-2-methylpropane sulfonic acid (AMPS), N,N'-methylenebisacrylamide (MBA) and potassium persulfate (KPS) as functional monomer, crosslinker and initiator respectively. Saturation magnetization value obtained for MMIP was 1.72emug^-1. Binding studies showed that MMIP exhibits good recognition to melamine compared to magnetic non imprinted polymer (MNIP). The optimum pH for the binding of melamine was found to be 4.5. Binding process was very fast and pseudo-second-order model fitted well with the kinetic data. Binding isotherm followed Langmuir isotherm model of monolayer adsorption with a maximum melamine binding efficiency of 62.25mgg^-1. The HPLC-UV analysis results revealed the applicability of MMIP in solid phase extraction and determination of melamine from milk samples.