Investigation of hydroxypropyl-β-cyclodextrin-based synergistic system with chiral nematic mesoporous silica as chiral stationary phase for enantiomeric separation in microchip electrophoresis

The separation of chiral amino acids using microchip electrophoresis (MCE) was investigated using chiral nematic mesoporous silica (CNMS) as the chiral stationary phase, with hydroxypropyl-β-cyclodextrin (HP-β-CD) as the chiral selector. Individually, neither CNMS nor HP-β-CD achieved separation, so they were combined. Ten chiral amino acids (phenylalanine, tryptophan, glutamic, alanine, serine, aspartic acid, cysteine, methionine, tyrosine, and histidine) were selected as the model analytes. Under optimized conditions, we achieved baseline separation of six chiral amino acids, and the other four chiral amino acids displayed improved resolution. These results indicate the presence of a synergistic effect between CNMS and HP-β-CD, showing that the combination of a chiral stationary phase and a chiral additive is a promising approach for enantioseparation using MCE.