S‐citalopram imprinted monolithic columns for capillary electrochromatography enantioseparations
Ali Derazshamshir, Ilgım Göktürk, Fatma Yılmaz, Adi̇l Deni̇zli̇
Abstract
Abstract In this study, the molecular imprinting method was used to separate enantiomeric forms of chiral antidepressant drug, R,S‐citalopram (R,S‐CIT) in aqueous solution by CEC system combining the advantages of capillary electrophoresis (CE) and high‐performance liquid chromatography (HPLC). For that, an amino acid‐based molecularly imprinted monolithic capillary column was designed and used as a stationary phase for selective separation of S‐citalopram (S‐CIT) for the first time. S‐CIT was selectively separated from the aqueous solution containing the other enantiomeric form of R‐CIT, which is the same in size and shape as the template molecule. Morphology of the molecularly imprinted (MIP S‐CIT) and non‐imprinted (NIP S‐CIT) monolithic capillary columns was observed by scanning electron microscopy. Imprinting efficiency of MIP S‐CIT monolithic capillary column used for selective S‐CIT separation was verified by comparing with NIP S‐CIT and calculated imprinting factor (I.F:1.81) proved the high selectivity of the MIP S‐CIT for S‐CIT. Cavities formed for S‐CIT form enabled selective ( α = 2.08) separation of the target molecule from the other enantiomeric R‐CIT form. Separation was achieved in a short period of 10 min, with the electrophoretic mobility of 7.68 × 10 −6 m 2 /Vs for R,S‐CIT at pH 7.0 10 mM PB and 50% ACN ratio. The performance of both MIP S‐CIT and NIP S‐CIT columns was estimated by repeating the R,S‐CIT separations with intra‐batch and inter‐batch studies for reproducibility of retention times of R,S‐CITs. Estimated RSD values that are lower than 2% suggest that the monolithic columns separate R,S‐CIT enantiomers without losing separation efficiency.