Exploration of The Selective Binding Property of The MIP-grafted Paper for Cochineal Dye

Abstract

A molecularly imprinted polymer (MIP) is a synthetic polymer that provides specific cavities for its analyte. In this study, the MIP specific to carminic acid, an insect-derived pigment, has been synthesized using methacrylic acid (MAA) and 4-vinyl pyridine (4Vpy) as monomers and ethylene glycol dimethacrylate (EDGMA) as a cross-linker. The imprinted surface particles were characterized by Scanning Electron Microscope (SEM). The rough surface of the synthesized MIP represented the specific binding site for carminic acid. The paper-based MIP polymerization was performed by pre-treatment the cellulose paper with aminopropyltriethoxysilane (APTES) before polymerization with the MIP solution. The novel membrane-grafted MIP exhibits good performance for selective recognition with the target carminic acid, which can be demonstrated by the imprinted factor of 1.94 as compared to those of nonimprinted polymer. According to the Scatchard analysis, it was estimated that there are two types of binding strategy, including high and low affinity, which corresponded to the Ka of 1.24x103 mM and 0.10 x103 mM, respectively. It was thus preliminary concluded that the membrane-grafted MIP fabricated in this study has the potential to be implemented in many applications such as extraction and pre-concentration.