Extraction of melamine from milk using a magnetic molecularly imprinted polymer

- Synthesized a sulfonic acid functionalised magnetic MIP for melamine extraction.
- The optimum pH for adsorption of melamine was found to be 4.5.
- The adsorption of melamine followed pseudo-second-order kinetic model.
- Maximum adsorption efficiency was 62.25 mg per gram of the imprinted polymer.
- The synthesized magnetic MIP was used for the extraction of melamine from milk.

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 1.72 emu g−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 62.25 mg g−1. The HPLC-UV analysis results revealed the applicability of MMIP in solid phase extraction and determination of melamine from milk samples.