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 Fe3 O4 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, Fe3 O4 @polynorepinephrine NPs (MIP-Fe3 O4 @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-Fe3 O4 @PNE NPs modified PDMS microchip. Moreover, the successful separation of histidine enantiomers on the MIP-Fe3 O4 @PNE NPs modified microchip using L-histidine as template molecule was also achieved.