电色谱模式下四肽印迹整体柱分子识别机理的研究

本文采用原位聚合法制备了以四肽YPLG为模板的毛细管分子印迹整体柱，在毛细管电色谱模式下以模板分子和它的结构类似物YPGL为样品，对分子印迹聚合物的识别机理进行了研究。这两种四肽由于化学结构相似且等电点非常相近，普通的电色谱和毛细管电泳方法分离非常困难。但我们的实验表明，印迹整体柱对模板分子具有特异性识别能力，因此YPLG与YPGL之间的分离因子为1.73，分离度达3.72。实验中系统地研究了流动相中有机溶剂的含量、缓冲溶液的pH值、缓冲溶液的盐浓度以及柱温对四肽识别的影响。实验中我们观察到模板在印迹柱上具有非线性的Van’t Hoff行为，揭示可能存在多重保留机理。本研究结果表明，在毛细管电色谱模式下，分子印迹整体柱的分子识别主要决定于样品与印迹聚合物之间的氢键作用以及印迹孔穴的三维结构。

Mechanism of Molecular Recognition on Tetrapetide‐imprinted Monolith by Capillary Electrochromatography

A tetrapeptide‐imprinted capillary monolithic column was synthesized successfully in the presence of YPLG (Tyr‐Pro‐Leu‐Gly) as template by in situ thermo‐initiated polymerization. For exploring the recognition mechanism of molecularly imprinted polymer in a capillary electrochromatography (CEC) mode, YPLG and its structural analogue, YPGL (Tyr‐Pro‐Gly‐Leu), differing in amino acid sequence, were used as model compounds. It is hard work to separate the two tetrapeptides by a simple CEC or a capillary electrophoresis mode due to their similar chemical structures and values of pI. However, the results showed that YPLG could be recognized specially by the imprinted monolith. The separation factor (α ′) and the resolution (R_s) between YPLG and YPGL were 1.73 and 3.72, respectively. The effects of organic modifier concentration, pH value of buffer, salt concentration of buffer and column temperature on the recognition of YPLG and YPGL were investigated. A non‐linear Van′t Hoff behavior of the template was observed on a YPLG‐imprinted column, which suggested the presence of multiple types of retention mechanisms or multiple types of binding sites. The results showed that the molecular recognition on MIP monolith in the CEC mode mainly derived from hydrogen bonding between YPLG and MIP and three‐dimensional structure of the imprinting cavities.