Liquid crystal-based molecularly imprinted nanoparticles with low crosslinking for capillary electrochromatography

•Liquid crystalline monomer was used as physical crosslinker to prepare MIP.•Monodisperse imprinted nanoparticles were prepared with zopiclone as template.•Baseline separation for zopiclone enantiomers was achieved with the nanoparticles in CEC mode.•The imprinted nanoparticles can retain affinity even at a level of cross-linker as low as 5%.

In this work, molecularly imprinted polymer (MIP) nanoparticles were prepared at a low level of crosslinking in the presence of liquid crystalline monomer as physical crosslinker to replace the most of chemical crosslinker. The imprinted nanoparticles against d-zopiclone were synthesized by precipitation polymerization using a mixture of methacrylic acid, ethylene glycol dimethacrylate, and liquid crystalline monomers. The resulting d-zopiclone imprinted nanoparticles were evaluated in capillary electrochromatography by partial filling technique. The resolution of enantiomer separation achieved on the d-zopiclone-imprinted nanoparticles was up to 3.29 and the column efficiency of zopiclone enantiomer (up to 66,900 plates/m) with good peak symmetry was obtained. The imprinted nanoparticles prepared in the presence of liquid crystalline monomer can retain affinity and specificity for template even when prepared with a level of cross-linker as low as 5%.