Dummy Templated Receptors Showing Enhanced Affinity for Vitamin D3

Vitamin D₃ (VD3) is an essential micronutrient, but its analytical determination in biological matrices is often hindered by structurally related metabolites and the limited selectivity of conventional analytical sorbents. The preparation of a molecularly imprinted polymer (MIP) using VD3 as a template is challenging due to its hydrophobic structure and lack of polar groups. Therefore, in this work, MIPs were prepared using the closely related structure hyodeoxycholic acid methyl ester as a template and tested for their adsorption capacity toward VD3. Several MIPs were first prepared using different functional monomers, and the results showed that 4-vinylpyridine (4VP) monomer in combination with divinylbenzene (DVB) as a crosslinker exhibited a relatively high binding capacity and imprinting factor. UV spectroscopy indicated an optimal VD3-monomer ratio of 1:4, while computational modeling further confirmed favorable interactions between VD3 and 4VP. The effect of incorporating styrene as a co-monomer with 4VP was also investigated, showing an enhancement in adsorption capacity with a slight increase in the imprinting factor. However, TGA analysis revealed that the thermal stability of the MIPs decreased with higher styrene content. Overall, the prepared MIPs demonstrated improved selectivity and recognition of VD3 compared to the non-imprinted polymers, offering a promising approach for its selective extraction and quantification.