Computational study and synthesis of multi-template molecularly imprinted polymer for isolating ethyl...

In recent years, research into molecularly imprinted polymers (MIPs) has expanded significantly, particularly for separation or isolation of analytes from extracts. MIPs designed for the simultaneous isolation of ethyl p-methoxycinnamate (EPMC) and ethyl cinnamate (EC) from Kaempferia galanga L. extract or multi-template molecularly imprinted polymer (MT-MIP) have been developed. However, the percentage recovery and purity have remained low. In this study, molecular modelling of MT-MIP for EPMC and EC was conducted using the semi-empirical Parametric Method 3 (PM3) to select functional monomers and determine the ratio of template molecule (TM) to functional monomer (FM). Geometry optimisation revealed that the HEMA formed a stable complex with the template molecule (ΔE of -92.33 kcal/mol). MT-MIPs were synthesised using HEMA at TM:FM molar ratios of 1:4 (MT-MIP-1) and 1:13 (MT-MIP-2), with an EPMC to EC ratio of 3:2, via bulk polymerisation. These polymers were employed as solid-phase extraction (SPE) adsorbents to isolate EPMC and EC from Kaempferia galanga L. extract. MT-MIP-2 exhibited a higher imprinting factor (IF) for both EPMC and EC compared to MT-MIP-1. The percentage recovery of EPMC using MT-MIP-2 for n-hexane, ethanol, and ethyl acetate extract were 65.89 %, 71.31 %, and 71.97 %. In addition, the percentage recovery of EC for n-hexane, ethanol, and ethyl acetate extract were 52.27 %, 60.79 %, and 63.36 % for the ethyl acetate extract. The purity of both EPMC and EC isolated using MT-MIP-2 exceeded 90 %. These findings demonstrate that MT-MIP-2 offers improved efficiency in the simultaneous isolation of EPMC and EC, making it a promising SPE adsorbent for natural product analysis. The separation step using MT-MIP-2 as SPE sorbent can replace the fractionation and sub-fractionation stages in EPMC and EC conventional isolation methods with high purity.