Construction and Studies of Histamine Potentiometric Sensors Based on Molecularly Imprinted Polymer

Abstract

Objective: Molecularly Imprinted Polymer (MIP)-modified potentiometric sensors for histamine (HIS) (as denoted as HIS sensor) have been developed. Methods: The MIPs comprise HIS, Methacrylic Acid (MAA) and ethylene glycol dimethacrylate as the template molecule, functional monomer and cross-linker, respectively. To examine the specificity of the MIP to HIS, the MIP particles were prepared with varying ratios of HIS: MAA and the HIS binding amount toward the MIP particles was determined by UV spectrophotometry. Furthermore, to quantitatively determine the ability of MIP (H2M20) to HIS, a HIS sensor was measured using Ag/AgCl as a reference electrode. Results: MIP particles having a HIS:MAA of 2 mmol:20 mmol (MIP (H2M20)) had the largest HIS binding amount among the MIP particles prepared. Additionally, MIP (H2M20) displayed a HIS binding amount approximately two times larger than the corresponding non-imprinted polymer (NIP) particles in the absence of template. The HIS sensor potential change increased as a function of HIS concentration and exhibited a near-Nernstian response of −25.7 mV decade−1 over the HIS concentration range of 1×10−5 to 1×10−4 mol L−1 with a limit of detection of 9.6×10−6 mol L−1. From the Nernstian response value, it was observed that the HIS sensor could detect the di-protonated HIS binding to the MIP. Conversely, when comparing at the same HIS concentration, the potential response value of the sensors fabricated using NIP particles were significantly smaller than the values of the corresponding HIS sensor. Conclusion: The MIP-modified potentiometric sensors can potentially be employed as an analytical method to quantitatively determine various analytes.