Preparation And Application Of Novel Molecularly Imprinted Monolithic Columns

Molecular imprinting technique is the process for preparation of molecularly imprinted polymer (MIP), which have the predetermined selectivity for the target molecules. The molecularly imprinted monolithic columns prepared by in situ polymerization of monomers have not only the high stereoselectivity of MIP, but also some advantages of simple preparation procedures, good reproducibility, low backpressure of column and low-consumption of template molecules. This thesis mainly focuses on the preparation of MIP monolithic column in a conventional chromatographic column or a capillary for chiral separation and solid-phase extraction (SPE) by high performance liquid chromatography (HPLC) or capillary electrochromatography (CEC).Two kinds of MIP monolithic columns were firstly in situ polymerized in stainless-steel columns by using (S)-1,1′-bi-2-naphthol (S-BNL) and (S)-(-)-Tr?ger's base (S-TB) as the imprinted template molecules, respectively. The effects of the content of acetic acid or water in mobile phase, temperature, sample loading and flow rate on the separation were systematically investigated. The fast enantioseparation of these two racemates on monolithic columns were successfully realized.A method for determination of analytes by on-line coupling a MIP monolithic column as the precolumn for SPE of samples with a reversed-phase C18 column was developed. The bisphenol A (BPA) imprinted monolithic column indicated good selectivity for BPA. Fast determination of BPA and other phenolic compounds in river water with on-line SPE by coupling monolithic precolumn with a commercially silica-based monolithic reversed-phase column was successfully acquired.Additionally, the l-tetrahyropalmatine (l-THP) imprinted monolithic column wasprepared, which could efficiently not only separate racemic THP, but also extract l-THP and other active ingredients in a traditional Chinese medicine (TCM), Corylidas yanhusuo.The MIP monolithic capillary column was also synthesized in a fused-silica capillary by in situ polymerization with methacrylic acid (MAA) as functional monomer. After optimizing the separation conditions, racemic TB and THP were baseline separated on S-TB and l-THP imprinted column by CEC, respectively. Furthermore, enantioseparation of BNL on the MIP capillary column prepared with basic 2-(dimethylamino)ethyl methacrylate (DAMA) as functional monomer was achieved in CEC.The MIP film was successfully grafted onto the surface of silica-based monolithic capillary column, which could be used for chiral separation by CEC and capillary liquid chromatography (cLC). Comparing with the organic MIP column, this kind of MIP-silica composite column showed better column efficiency. As the backbone of silica monolith was explored for preparation of this MIP organic-inorganic hybrid monolith, the difficulty for selection of porogens associated with the preparation of organic monolithic column can be eliminated, thus resulting in extending the application area of the imprinted molecules.