表面增强喇曼光谱研究聚合物在金属表面的排列形态

本文报道了用硝酸刻蚀金属片的方法制备有表面增强喇曼散射(SERS)活性的金属表面,研究聚(4-乙烯基吡啶)(P4VP)和聚苯并咪唑(PBIM)的SERS光谱。证明这种方法比经典的Ag/CaF_2岛膜法有较大的增强因子和较好的热稳定性。通过对P4VP和PBIM分子中环的振动模式的分析,发现不同的成膜制样方法导致聚合物分子在金属表面不同的排列形态,在一定条件下,有的排列方式可发生转化。     

A new substrate for surface enhanced Raman scattering of dye Sudan molecules

A new SERS substrate was prepared using electro-polishing aluminum foils. Based on these high active SERS systems, surface enhanced Raman scattering (SERS) of Azo Dye Sudan were performed and carefully studied based on this highly active SERS substrate. High quality SERS spectra were obtained, which indicates that this kind of coarse aluminum foils is an active SERS substrate. Numbers of additional modes were presented, as well as some split peaks, which may be a consequence of symmetry lowering.     

硝酸刻蚀银表面的增强拉曼光谱及其在表面化学中的应用

最近,我们摸索出的硝酸刻蚀法制备有SERS(Surface Enhanced Raman Scattering,表面增强拉曼散射)活性的银表面,有良好的热稳定性,且费用低廉,预期在研究金属表面反应、催化和金属-聚合物界面结构等方面可发挥作用。在展示了这一新方法具有极高的表面增强因子后,本文介绍用该法研究吸附质的自集合(self-assembly)和表面取向结果。     

增感染料1556、798吸附在银电极上的表面增强拉曼光谱

本文利用表面增强拉曼光谱研究了增感染料1556、798在银电极上的吸附,通过比较染料的固体拉曼光谱和染料的表面增强光谱,我们发现两种染料在银电极表面的吸附行为不完全相同,吸附时染料分子的平面基本上与电极表面相垂直。     

吡啶-氯化钾水溶液/n型硫化镉电极界面上的表面增强喇曼散射

本文研究了在吡啶-KC1水溶液中吡啶吸附在n-CdS电极上的表面增强喇曼散射(SERS)。在光照下,CdS电极经过正极化予处理数分钟,就能观察到吡啶吸附在CdS电极上的很强的SERS谱。其特征峰是1010和1036cm^-1与纯吡啶的喇曼特征峰991,1030cm^-1相比有了明显位移。又SERS谱随着吡啶浓度的增加而增强。外加电位对SERS也有一定影响,其曲线形状与CdS的I～V曲线很相似。对这些实验结果,本文用n型CdS电极的光电化学特性进行了初步的考察和讨论。     

Ag|kCl|六氢吡啶体系表面增强喇曼散射效应的猝灭和恢复

在简述近年来电化学体系中表面增强喇曼散射(SERS)活性位置研究的实验结果和有关论述后, 着重报道作者在Ag/KCl/六氢吡啶体系中, Ag-Cl振动峰和六氢吡啶诸振动峰的强度, 在一定电位范围内电极被施加负脉冲电位后的同步下降, 以及采用氧化还原循环(ORC)处理得到同步恢复等新的实验结果, 并对上述体系中表面络合物的构成及其在SERS中的作用作了进一步的论证。     

SERS谱峰对电极电位阶跃的不同响应速率的证据

八十年代以来,人们除继续研究表面增强拉曼散射(SERS)效应的复杂机理和发现有关新体系外,逐渐将注意力集中在将SERS 技术应用于生物、分析和电化学研究,以获得固/液体系的界面结构和吸     

Self-assembled metal colloid films: two approaches for preparing new SERS active substrates

In this paper, we propose two new approaches for preparing active substrates for surface-enhanced Raman scattering (SERS). In the first approach (method 1), one transfers AgI nanoparticles capped by negatively charged mercaptoacetic acid from a AgI colloid solution onto a quartz slide and then deoxidizes AgI to Ag nanoparticles on the substrate. The second approach (method 2) deoxidizes AgI to Ag nanoparticles in a colloid solution and then transfers the Ag nanoparticles capped by negatively charged mercaptoacetic acid onto a quartz slide. By transfer of the AgI/Ag nanoparticles from the colloid solutions to the solid substrates, the problem of instability of the colloid solutions can largely be overcome. The films thus prepared by both approaches retain the merits of metal colloid solutions while they discharge their shortcomings. Accordingly, the obtained Ag particle films are very suitable as SERS active substrates. SERS active substrates with different coverages can be formed in a layer-by-layer electrostatic assembly by exposing positively charged surfaces to the colloid solutions containing oppositely charged AgI/Ag nanoparticles. The SERS active substrates fabricated by the two novel methods have been characterized by means of atomic force microscopy (AFM) and ultraviolet-visible (UV-vis) spectroscopy. The results of AFM and UV-vis spectroscopy show that the Ag nanoparticles grow with the increase in the number of coverage and that most of them remain isolated even at high coverages. Consequently, the surface optical properties are dominated by the absorption due to the isolated Ag nanoparticles. The relationship between SERS intensity and surface morphology of the new active substrates has been investigated for Rhodamine 6G (R6G) adsorbed on them. It has been found that the SERS enhancement depends on the size and aggregation of the Ag particles on the substrates. Especially, we can obtain a stronger SERS signal from the substrate prepared by method 1, implying that for the metal nanoparticles capped with stabilizer molecules such as mercaptoacetic acid, the in situ deoxidization in the film is of great use in preparing SERS active substrates. Furthermore, we have found that the addition of Cl- into the AgI colloid solution changes the surface morphology of the SERS active substrates and favors stronger SERS enhancement.     

苯骈噻唑类化合物在银电极表面上的SERS

自七十年代中期,吸附在银电极表面上的吡啶的表面增强拉曼散射效应被发现以来,大量的有关表面增强拉曼散射效应的研究集中在含氮有机化合物上.对含硫化合物,尤其是对含硫和氮的杂环化合物的研究较少.在六十年代中期,Califano,Sbrana 和Davidovics 等人及其合作者分别研究了噻唑和异噻唑的红外和拉曼谱.本文研究了含巯基化合物,即系列的苯骈噻唑类化合物的普通拉曼谱(NRS)及其吸附在银电极表面上所产生的表面增强拉曼谱(SERS),并讨论了噻唑杂环上不同取代基对谱图的影响.     

Surface-enhanced Raman scattering of some water insoluble drugs in silver hydrosols

An extraction method has been used to obtain surface-enhanced Raman scattering (SERS) spectra of water insoluble drugs such as aspirin, salicylic acid, acetaminophen, and vitamin A acid. This method is based on the strong affinity of the sample molecules to the silver particle surfaces. Results from the present study indicate that the method can be extended to identify and analyze many other water insoluble compounds by SERS. The high sensitivity of SERS and the linear calibration curve make it feasible in the trace quantitative analysis; the low limit of detection is comparable or better than those of calorimetric and spectrophotometric methods.     

基于表面增强拉曼光谱技术对医疗美容产品中正壬酸香草酰胺的快速检测

以银纳米线为拉曼基底,运用表面增强拉曼光谱技术(SERS)建立了对发热剂中正壬酸香草酰胺的检测方法。采用简便有效的两步滴加多元醇法制备了具有SERS活性的银纳米线,利用扫描电镜和紫外-可见光谱仪对银纳米线进行了表征。对正壬酸香草酰胺进行了SERS研究并对正壬酸香草酰胺的SERS谱带进行了归属。正壬酸香草酰胺的质量浓度在1~1.0×10^-8mg/L范围内与其在1588 cm^-1处的SERS特征峰强度有良好的线性关系,方法的最低检出浓度可达0.66 pg/L。对样品进行前处理后,运用加标回收法考察其回收率。该方法可以用于发热剂中正壬酸香草酰胺的检测。     

Magnetic assistance highly sensitive protein assay based on surface-enhanced resonance Raman scattering

A simple and effective surface-enhanced Raman scattering (SERS)-based protocol for the detection of protein-small molecule interactions has been developed. We employed silver-coated magnetic particles (AgMNPs), which can provide high SERS activity as a protein carrier to capture a small molecule. Combining magnetic separation and the SERS method for protein detection, highly reproducible SERS spectra of a protein-small molecule complex can be obtained with high sensitivity. This time-saving method employs an external magnetic field to induce the AgMNPs to aggregate to increase the amount of atto610-biotin/avidin complex in a unit area with the SERS enhancement. Because of the contribution of the AgMNP aggregation to the SERS, this protocol has great potential for practical high-throughput detection of the protein-small molecule complex and the antigen-antibody immunocomplex.     

Detection of SERS active labelled DNA based on surface affinity to silver nanoparticles

Developments in specific DNA detection assays have been shown to be increasingly beneficial for molecular diagnostics and biological research. Many approaches use optical spectroscopy as an assay detection method and, owing to the sensitivity and molecular specificity offered, surface enhanced Raman scattering (SERS) spectroscopy has become a competitively exploited technique. This study utilises SERS to demonstrate differences in affinity of dye labelled DNA through differences in electrostatic interactions with silver nanoparticles. Results show clear differences in the SERS intensity obtained from single stranded DNA, double stranded DNA and a free dye label and demonstrate surface attraction is driven through electrostatic charges on the nucleotides and not the SERS dye. It has been further demonstrated that, through optimisation of experimental conditions and careful consideration of sequence composition, a DNA detection method with increased sample discrimination at lower DNA concentrations can be achieved.     

SnO2纳米粒子作为SERS基底的研究

采用溶胶-水热法制备了不同尺寸的SnO2纳米粒子, 并将其作为表面增强拉曼散射(Surface-enhanced Raman scattering, SERS)活性基底, 重点探讨了表面缺陷能级与SERS性能的关系. 观察到4-巯基苯甲酸(4-MBA)吸附在150 ℃水热合成的SnO2纳米粒子上的SERS 信号最强, 随着在空气中煅烧温度的升高, SERS信号逐渐减弱. 分别用透射电子显微镜、 紫外-可见光谱、 荧光光谱、 X射线衍射和X射线光电子能谱对SnO2纳米粒子进行了表征. 结果表明, SnO2纳米粒子的表面氧空位和缺陷等表面性质在增强拉曼散射性能中发挥着重要的作用, 表面氧空位和缺陷等含量越高其SERS信号就越强.     

Preparation of Surface-enhanced Raman Scattering(SERS)-active Optical Fiber Sensor by Laser-induced Ag Deposition and Its Application in Bioidentification of Biotin/Avidin

A surface-enhanced Raman scattering(SERS) optical fiber sensor was prepared by the laser-induced deposition of Ag nanoparticle membrane on a silica optical fiber tip, which was applied to the real time SERS spectral monitoring on the biorecognition of biotin/avidin. The bioidentification of biotin/avidin was carried out through a indirect method, in which the bioidentification is based on the SERS response signal of a labeled dye(Atto610) after its fluorescence has been quenched totally by the deposited Ag nanoparticle membrane. By SERS monitoring the bioidentification process of biotin/avidin, it has been found that this recognition process is finished in 40 min. The lowest detection concentration of biotin is 1.0×10^-7 mg/mL. This research is promising in the application of immunoassays on line and in vivo.     

农产品中脱氧雪腐镰刀菌烯醇的表面增强拉曼检测

利用便携式拉曼光谱仪建立了一个快速筛查与检测谷物中真菌毒素脱氧雪腐镰刀菌烯醇(DON)的表面增强拉曼散射(SERS)方法。首先利用实验室前期开发的方法制备了具有高活性的水凝胶SERS芯片。该SERS芯片是将预先制备的高SERS活性的单层碳基点(CDs)包裹的银纳米颗粒团聚体(a-AgNPs/CDs)与聚乙烯醇(PVA)水溶液混合均匀后,再利用循环冷冻-解冻的物理交联法制备而成的。实验优化了影响水凝胶SERS芯片对DON的SERS响应的实验条件,包括溶剂、浸泡温度和浸泡时间。在最佳的SERS检测条件下(溶剂为水-乙醇(1:1, v/v),浸泡温度为40 ℃,浸泡时间为5 min), DON的线性响应范围为1~10000 μg/kg(相关系数(R²)=0.9967),检出限(LOD)为0.14 μg/kg,表明该SERS基底具有较高的灵敏度。得益于水凝胶特殊的孔径结构,实际样品基质中常见的糖、蛋白质、油脂、色素等干扰物质都被阻隔在水凝胶外。因此,在复杂样品检测中仅需要简单的提取,而不需要复杂的分离处理。将该方法用于小麦粉中DON的检测,所得回收率为97.3%~103%,相对标准偏差为4.2%~5.0%。实验结果表明所建立的检测DON的SERS方法具有响应范围宽、灵敏度高、重复性好、响应迅速、操作简单、抗干扰能力强等优点,这说明本实验室所构建的水凝胶SERS芯片在粮食中生物毒素的快速筛查与检测方面具有良好的应用潜力。     

金属衬底上石墨烯的控制生长和微观形貌的STM表征

目前化学气相沉积(CVD)方法在不同的金属基底上大规模生长获得石墨烯得到了广泛的应用; 同时扫描隧道显微镜(STM)做为一种强大的精细直观的研究手段可以用于表征金属衬底上石墨烯的微观形貌, 指导石墨烯的控制生长. 本文侧重于Cu箔、Pt 箔和Ni 衬底上石墨烯的控制生长、表面微观形貌、表面缺陷态、堆垛形式的阐述, 得到结论: (1) 两种溶碳量较低的金属(Cu, Pt)上, 石墨烯的生长都符合表面催化的生长机制, 同时层间的范德华相互作用也可以诱导双层石墨烯的生长; (2) 衬底粗糙度的增加可以使石墨烯的电子态去简并化, 从而破坏石墨烯面内π键共轭结构, 导致部分碳原子转变为sp³杂化; (3) 原生的褶皱是由于界面热膨胀系数失配所导致; (4) Pt 箔表面石墨烯的平整度要远优于Cu箔表面的石墨烯, 且不同晶面共存的基底对于石墨烯的连续性并没有产生显著的影响.     

XPS法测量铝箔表面氧化铝的厚度

介绍了一种无需溅射、无需变角，只需一次简单的ＸＰＳ（Ｘ射线光电子能谱）窄扫描，即可根据谱图中氧化态和金属态的相对强度算出铝金属表面氧化铝的厚度。用该法测量了一系列不同方法处理的铝表面氧比铝厚度，并与椭偏法及ＮＲＡ法（核反应分析法）测定结果进行了对比，结果表明，该法是一种简便准确的膜厚测量法。