胶体金核壳型沙丁胺醇分子印迹聚合物的光谱特征分析

Spectroscopic Study of Salbutamol Molecularly Imprinted Polymers

为了解决饲料和动物产品中沙丁胺醇残留现场快速检测的难题,开发以分子印迹技术为基础的快速检测沙丁胺醇的新方法,使用沙丁胺醇做为模板分子,甲基丙烯酸(methacrylic acid,MA)作为功能单体,以本体聚合法为基础合成常规SAL分子印迹聚合物(molecularly imprinted polymer,MIPs)和非分子印迹聚合物(non imprinted polymer NIPs)。在此基础上,以胶体金粒子为引发核,制备出新型的核壳型沙丁胺醇MIPs。应用紫外吸收光谱(UV spectra)、傅里叶红外光谱(IR spectra)和拉曼光谱(Raman spectru)、扫描电镜(scanning electron microscopy,SEM)等技术手段获得两种印迹物及各种相关化合物的光谱图、电镜图等表征图像。由实验结果可知,SAL和MA上的羧基形成稳定又容易洗脱的1∶1型氢键配合物,化学结合常数K=-0.245×10~6 L^2·mol^(-2)。与MA的—COOH中氢原子形成氢键的可能结合位点是SAL C—O中的氧原子。MIPs与MA中—OH的吸收峰比较可知,前者明显红移;证明SAL作为模板分子与MA之间发生特定结合。未洗脱MIPs的C—O的伸缩振动产生的吸收峰红移;即能量损失明显,可知MA中—COOH的氢原子如果要生成氢键,可能的结合位点就是SAL分子内C—O中的氧原子。MIPs和NIPs中C—C,C—O,—OH等吸收明显的官能团峰型大致相同。将MIPs洗脱掉作为模板分子的SAL后,留下了含有特殊且确定结构官能团化学及空间构成均与SAL高度匹配的空穴,可与待测液中的目标检测分子SAL发生特异性识别和专一结合作用。而胶体金核壳型MIPs与常规MIPs相比,除具有以上相同特点外,其表面更加松散,表面孔穴明显增多。由此增加了吸附目标分子的有效面积,具有更优良的吸附性能。这两种印迹物的合成及光谱特征分析为建立基于分子印迹技术的快速检测SAL新方法奠定了理论和实践基础。

In order to solve the problem of on-site rapid detection of salbutamol residues in feed and animal products,and develop a new method of fast detection of salbutamol on the basis of the molecular imprinting technology,this article uses the salbutamol（SAL）working as template molecule,methacrylic acid（MAA）working as functional monomer.On this basis,a new type of core-shell type salbutamol molecularly imprinted polymers were prepared with colloidal gold particles as triggering core.Superficial characteristics of the MIPs and the related compounds were investigated by ultraviolet（UV）spectra and infrared（IR）spectra,Raman spectra,Scanning electron microscopy（SEM）respectively.The results indicated that a stable hydrogen bonding complex has been formed between the carboxyl groups of SAL and MA with a matching ratio of 1∶1.The complex can be easily eluted by the reagent containing hydrogen bonding.The chemical binding constant K reaches-0.245×10~6 L^2·mol^（-2）.The possible binding sites of the hydrogen bonding was formed between the hydrogen atoms of—COOH in MA and the oxygen atoms of C—O inSAL.IRandRamanspectrumshowedthat,compared with MA,a significant red shift of—OH absorption peak was manifested in MIPs,which proved that SAL as template molecule occurred a specific bond between MA.Red shift of stretching vibration absorption peak of C—O was also detected in the un-eluted MIPs and obvious energy loss happened,which demonstrated a possible bindingsites is SAL intramolecular of C—O atom of oxygen.If the hydrogen atoms of—COOH in MA wanted to generate hydrogen bond.However,the shapes of absorption peak of other functional groups including C—C,C—O, and —OH were very similar both in MIPs and NIPs.Specific cavities were formed after the template molecules in MIPs were removed.It was proved by the adsorption experiment that the specific sites in these cavities highly match with the chemical and space structure of SAL.Besides,colloidal gold type core-shell molecularly imprinted polymers have looser surface,more cavities in the surface compared with ordinary molecularly imprinted polymers,which increased the effective area of adsorption to target molecules.So it have better performance in adsorption.Based on the principle that these cavities can specificly recognize and combine with target molecule in the test sample,and the excellent ability of colloidal gold core-shell molecularly imprinted polymers,the development of novel methods for fast determination of SAL based on the molecular imprinting technology can be expected in the near future.