【作者】 郭志男；

【导师】 赵冰；

【作者基本信息】 吉林大学 ， 分析化学， 2014， 博士

【摘要】 本论文从新型的表面增强拉曼光谱（SERS）超灵敏检测方法的开发着手，一方面通过SERS基底上“热点”的可控构筑制备了新型的SERS活性基底，使SERS作为分析手段具有稳定性高、增强能力高、重现性好等优点；另一方面通过SERS技术和其它与分析化学相关的辅助技术联用，建立基于SERS的实际样品分析的方法，应用到有害物质的检测当中。本论文创新点主要有以下几个方面：1.通过在基片上以可控的方式构筑纳米哑铃结构作为SERS活性基底，实现对2,4,6-三硝基甲苯(TNT)的超灵敏检测。这种纳米哑铃结构是由两个电性相反的金纳米粒子通过静电吸附作用构成。在两种纳米粒子连接处有强度很高的表面电磁场，此处被视为体系中的“热点”。位于此区域的标记分子的拉曼信号会被极大增强。通过体系中TNT分子浓度和构筑的纳米哑铃结构热点数量的对应关系我们间接的完成了对TNT分子的检测。2.通过磁性印迹表面增强拉曼光谱(MI-SERS)方法实现对混合体系中环丙沙星的超灵敏检测。这一新的MI-SERS方法是由磁性分离技术、分子印迹技术、SERS技术相结合的分析方法。该方法同时具备了对目标分子特异性提取、快速分离和检测灵敏度高的特点。使得整个检测过程可以在十分钟之内完成，最终的检测限度可以达到10-7摩尔每升。3.利用金纳米壳层芯片实现了对牛奶中三聚氰胺分子的一步SERS检测。通过自组装的方法将金纳米壳层粒子组装到基片表面制备出新型的SERS活性基底。由于在纳米粒子壳层上具有许多“热点”，使得该基底具有很高的SERS活性。再加上芯片基底的富集效果，可以大大提高对混合样品中三聚氰胺的检测能力。实验结果表明这种芯片对实际样品中三聚氰胺含量的监控具有很大的应用潜力。更多还原

【Abstract】 Raman spectroscopy is a versatile tool to gain structural information of complexmolecules under in situ conditions. The intrinsically low Raman signal intensity canbe great enhanced for molecules attached to metallic/plasmonic surfaces by theinteraction of the oscillating electric field of the radiation and the surface plasmons ofthe metal. The resultant surface enhanced Raman phenomenon is associated with anincreased sensitivity, which is enhanced up to10-14orders of magnitude overconventional Raman spectroscopy. Thus surface enhanced Raman spectroscopy(SERS) is a desirable technique to selectively probe trace amounts of analyte in manykinds of system. SERS as an ultrasensitive detection method, has great potential forchemical and biological sensing and imaging applications not only because it isselective and sensitive, but also because it gives little interference from water. Inaddition, since Raman spectra are dominated by the characteristic vibrationalfingerprint of the target molecules SERS offers great advantages when it is applied tostudy complicated systems. Compared to fluorescence spectroscopy, Raman bands aremuch narrower than fluorescence emission bands. Thus, based on the unique Ramansignature of each molecule, SERS can be applied for the detection of several targets atthe same time. Due to its high surface sensitivity and discrimination ability SERScould be a promising analytical method for food safety analysis, drug analysis,explosive detection and environmental pollutant monitoring. However, for different target, differentstrategy of SERS method should be designed and conducted. Thefollowing parts which is included in the thesis, demonstrates how to apply a SERSmethods for hazard detection:(1) Ultrasensitive trace analysis for2,4,6-trinitrotoluene using nanodumbbellsurface-enhanced Raman scattering hot spotsWe develop an ultra-sensitive surface-enhanced Raman scattering (SERS)-baseddetection system for2,4,6-trinitrotoluene (TNT) using nano-dumbbell structuresformed by the electrostatic interaction between positively and negatively charged goldnanoparticles. First, Meisenheimer complexes were produced between TNT andL-cysteine on gold substrates, and4-mercaptopyridine (4-MPY) labeled goldnanoparticles (positively charged) were allowed to interact with the Meisenheimercomplexes through the electrostatic interaction between the negatively chargedaromatic ring of the complex molecules and the positively charged nanoparticles.Then, negatively charged gold nanoparticles were added in order to formnano-dumbbells. As a result, many hot junctions were generated by thedumbbellstructures, and the SERS signals were greatly enhanced. Our experimental resultsdemonstrate that the SERS-based assay system using nano-dumbbells provides anultra-sensitive approach for the detection of TNT explosives. It also shows a strongpotential for broad application in detecting various explosive materials used formilitarypurposes.(2) Magnetic imprinted surface enhanced Raman scattering (MI-SERS) basedultrasensitive detection of ciprofloxacin from a mixed sampleA new method for fast extraction and ultra-sensitive detection of ciprofloxacin basedon magneticimprinted surface-enhanced Raman scattering (MI-SERS) has beendeveloped in this part. This methodis a combination of three techniques, which are amagnetic separation technique, a molecular imprintingtechnique and asurface-enhanced Raman scattering technique. We designed and fabricatedcore–shellstructured magnetic molecularly imprinted polymers (MIPs) which can be applied to specificallyrecognise ciprofloxacin and extract it from a mixed system. Thewhole extraction and clean-upprocedures are assisted by a magnetic field, whichmakes it much easier than traditional centrifugalseparation. In addition to this,surface-enhanced Raman scattering (SERS) was applied as the detectiontool, whichmakes the detection limit for ciprofloxacin by this method as low as10-9molL-1.Furthermore, we integrated these core–shelled magnetic-MIPs on a magnet chipand detectedciprofloxacin from fetal bovine serum. The whole detection process canbe finished within ten minutesand the limit of detection by this chip can reach10-7mol L-1.(3) One-Step Detection of Melamine in Milk by Hollow Gold Chip Based onSurface-enhanced Raman ScatteringA hollow gold (HG) chip with high surface-enhanced Raman scattering (SERS)capability was fabricated and used to monitor the adulteration of milk with melamine.This chip was fabricated with self-assembled hollow gold nanospheres (HGNs) onglass wafers through electrostatic interaction. There are two important advantages forthe use of this HG chip as a detection platform. First, HGNs show a strong SERSenhancement from individual particles due to their capability to localize theelectromagnetic fields around the pinholes in hollow shells. Second, the HG chipimproves the limit of detection through the enrichment effect. The characteristicSERS peak of melamine was used to distinguish it from other kinds of proteins oramino acids, and its intensity was used to monitor the percentage of melamine in milk.With its simple detection procedure (no pretreatment or separation steps), decreasedprocessing time and low detection limit, this HG chip shows a strong potential forbroad applications in melamine detection from real samples.更多还原