title: Preparation and evaluation of a monolithic molecularly imprinted polymer for the chiral separation of neurotransmitters and their analogues by capillary electrochromatography.
abstract: A monolithic molecularly imprinted polymer (MIP) column was prepared as the stationary phase for the capillary electrochromatographic (CEC) separation of a group of structurally related compounds including dopamine (DA), (±)-epinephrine (EP), (-)-isoproterenol (ISO), (±)-norepinephrine (NE), (±)-octopamine (OCT), and (±)-synephrine (SYN). Here, (-)-NE was used as the template. Either methacrylic acid (MAA) or itaconic acid (IA) together with a mixture of ethylene glycol dimethacrylate (EDMA) and α,α'-azobis(isobutyronitrile) (AIBN) in N,N-dimethylformamide (DMF) was introduced into a pre-treated, silanised, fused-silica capillary by a thermal non-covalent polymerisation procedure. Optimised conditions for the polymerisation reaction were assessed by the separation efficiency of the template. Both the template/monomer/cross linker molar ratio and the compositions of the functional monomer, cross-linker, and porogen affected polymerisation. The optimum in situ polymerisation reaction was performed at 65 °C for 17 min. By varying CEC parameters like eluent composition and pH, we observed that the addition of SDS to the eluent clearly improved the CEC separations. With a mobile phase of citrate buffer (10 mM, pH 3)/SDS (40 mM)/acetonitrile (2/2/1, v/v/v) solution and an applied voltage of 10 kV, the six related structures of the template and their enantiomeric mixtures were satisfactorily separated at 30 °C.
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Bao-Yu
authors.initials: BY
authors.lastname: Huang
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Chen
authors.forename: Guan-Ren
authors.initials: GR
authors.lastname: Wang
authors.forename: Chuen-Ying
authors.initials: CY
authors.lastname: Liu
mesh_terms: D002021:Buffers; D053801:Capillary Electrochromatography / Q000379:methods*; D002395:Catecholamines / Q000737:chemistry / Q000302:isolation & purification* / Q000652:urine; D004355:Drug Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D054802:Molecular Imprinting / Q000379:methods*; D018377:Neurotransmitter Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000652:urine; D013237:Stereoisomerism
chemical_list: D002021:Buffers; D002395:Catecholamines; D018377:Neurotransmitter Agents