Chemical Sensor Based on Molecularly Imprinted Organic-Organic Nanocomposite Film for the Analysis of Melamine in Infant Formula

Abstract

Melamine (MA) is non-edible synthetic chemical intentionally added to foodstuffs such as milk and milk products including infant formula as the fake source of protein. Many evidences confirmed that this molecule is primarily responsible for kidney failure by forming kidney stones and then blocking the renal tubes. Therefore, a simple, sensitive and rapid method for online quantification of MA can avoid the consumption of milk products contaminated with MA and possible health risks resulted both socially and economically. The present work reports the development of a chemical sensor from aniline (ANI) and acrylic acid (AA) copolymer films by using concurrent electrochemical polymerization method using MA as a template. After optimization of important parameters and template removal, the performance of the film formed was studied by cyclic and differential pulse voltammetry. The proposed sensor showed a linear current response with various concentrations of MA. The linear range, limit of quantification and limit of detection were 0.1-200 x10-9 M, 5.73x10-11M, 1.72 x10-11M respectively. The sensitivity and selectivity of the sensor achieved may attribute to the synergistic effect of different functional units found on the polymer composite. These functional units competitively bind the template with non-covalent interactions. The sensor was also applied to analyze milk samples and obtained a recovery of 95.87-105.63% with RSD 1.11-2.23%. The good stability and reusability as well as strong affinity to the imprint molecule make the imprinted copolymers the promising functional materials for future sensor development.