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%.