Abstract: A polymeric membrane ion-selective electrode for determination of melamine is described in this paper. It is based on a molecularly imprinted polymer (MIP) for selective recognition, which can be synthesized by using melamine as a template molecule, methacrylic acid as a functional monomer and ethylene glycol dimethacrylate as a cross-linking agent. The membrane electrode shows near-Nernstian response (54ámV/decade) to the protonated melamine over the concentration range of 5.0áÎá10-6 to 1.0áÎá10-2ámoláL-1. The electrode exhibits a short response time of ~16ás and can be stable for more than 2 months. Combined with flow analysis system, the potentiometric sensor has been successfully applied to the determination of melamine in milk samples. Interference from high concentrations of ions co-existing in milk samples such as K+ and Na+ can be effectively eliminated by on-line introduction of anion- and cation-exchanger tandem columns placed upstream, while melamine existing as neutral molecules in milk of pH 6.7 can flow through the ion-exchanger columns and be measured downstream by the proposed electrode in an acetate buffer solution of pH 3.7
Template and target information: melamine, 2,4,6-triamino-benzo-1,3,5-triazine
Author keywords: molecularly imprinted polymer, potentiometric sensor, Melamine, Ion-selective electrode, Flow analysis