Separation of chiral compounds using magnetic molecularly imprinted polymer nanoparticles as stationary phase by microchip capillary electrochromatography

In this work, a simple and rapid approach was developed for separation and detection of chiral compounds based on a magnetic molecularly imprinted polymer modified poly(dimethylsiloxane) (PDMS) microchip coupled with electrochemical detection. Molecularly imprinted polymers were prepared employing Fe₃O₄ nanoparticles (NPs) as the supporting substrate and norepinephrine as the functional monomer in the presence of template molecule in a weak alkaline solution. After extracting the embedded template molecules, Fe₃O₄@polynorepinephrine NPs (MIP–Fe₃O₄@PNE NPs) showed specific molecular recognition selectivity and high affinity towards the template molecule, which were then used as stationary phase of microchip capillary electrochromatography for chiral compounds separation. Mandelic acid and histidine enantiomers were used as model compounds to test the chiral stationary phase. By using R‐mandelic acid as the template molecule, mandelic acid enantiomer was effectively separated and detected on the MIP‐Fe₃O₄@PNE NPs modified PDMS microchip. Moreover, the successful separation of histidine enantiomers on the MIP–Fe₃O₄@PNE NPs modified microchip using L‐histidine as template molecule was also achieved.