Chiral resolution of salbutamol in plasma sample by a new chiral ligand-exchange chromatography method after its extraction with nano-sized imprinted polymer

• Salbutamol enantiomers were resolved by the chiral ligand exchange chromatography.
• (l)-Alanine and Cu(II) were used as chiral dopant and complexing ion, respectively.
• The kind of cooper salt was found to be crucial factor in the enantioseparation.
• DFT was employed to substantiate the separation mechanism and anion effect.
• Sulbutamol-imprinted polymer was used for sample preparation before its analysis.

A new chromatographic procedure, based upon chiral ligand-exchange principal, was developed for the resolution of salbutamol enantiomers. The separation was carried out on a C18 column. (l)-Alanine and Cu2+ were applied as chiral resolving agent and complexing ion, respectively. The kind of copper salt had definitive effect on the enantioseparation. Density functional theory (DFT) was used to substantiate the effect of various anions, accompanying Cu2+, on the formation of ternary complexes, assumed to be created during separation process. The DFT results showed that the anion kind had huge effect on the stability difference between two corresponding diastereomeric complexes and their chemical structures. It was shown that the extent of participation of the chiral selector in the ternary diastereomeric complexes formation was managed by the anion kind, affecting thus the enantioseparation efficiency of the developed method. Water/methanol (70:30) mixture containing (l)-alanine–Cu2+ (4:1) was found to be the best mobile phase for salbutamol enantioseparation. In order to analyze sulbutamol enantiomers in plasma samples, racemic salbutamol was first extracted from the samples via nano-sized salbutamol-imprinted polymer and then enantioseparated by the developed method.