银纳米片在无纺布纤维上的可控组装及其SERS效应

以无纺布(NWF)为支撑基体, 采用两步化学合成法在NWF上原位构建了由间隙为20~110 nm Ag纳米片(AgNS)组装成的AgNS@NWF微纳结构. 扫描电子显微镜(SEM)分析表明, AgNS@NWF具有特殊的层级结构, 该结构可用于表面增强拉曼散射(SERS)研究. 实验结果表明, AgNS@NWF微纳结构具有良好的SERS灵敏度和优异的信号可重现性. 将罗丹明6G(R6G)作为SERS探针分子, 发现R6G的SERS特征峰强度的对数值与R6G水溶液的浓度对数值呈良好的线性关系, 最低检测限可达1×10^?10 mol/L, 表明AgNS@NWF微纳结构具有良好的SERS灵敏度; 当R6G水溶液的浓度为1×10^?5, 1×10^?6和1×10^?7 mol/L时, 610 cm^?1处谱带拉曼散射强度的相对标准偏差分别为3.57%, 3.67% 和8.46%, 优于或接近于以往研究, 表明AgNS@NWF微纳结构具有优异的信号可重现性. 将3-巯基丙酸和三聚氰胺作为SERS的检测分子, 最低检测限分别为1×10^?5和1×10^?6 mol/L. 本文为制备灵敏度高、 信号可重现性优异的SERS基底提供了一种简单、 快速、 成本低廉的方法, 在生物检测和环境监测中具有潜在的应用价值.     

微通道SERS器件的制备及对有害化学品的检测

在微通道内表面通过化学吸附组装上银纳米粒子制成了微通道表面增强拉曼散射(SERS)器件,其对常见探针分子罗丹明6G(R6G)和4-巯基吡啶(4-MPY)的最低检测浓度分别达到10-11和10-8mol/L,说明其具有很好的增强效果.用该器件对2种有害化学药品进行了检测,三聚氰胺的最低检测浓度可到10-6mol/L,而福美双的最低检测浓度可达到10-7mol/L,说明所制备的微通道器件可用于对有害化学品的检测.微通道SERS器件具有体积小、取样少、制备简单、能够进行现场实时动态检测等特点,具有广阔的应用前景.     

预聚集法制备单层银纳米粒子膜及其SERS活性研究

提出一种预聚集方法来制备单层银纳米粒子膜, 获得了高活性的表面增强拉曼散射基底. 利用紫外-可见吸收光谱、TEM, SEM等表征手段分析了预聚集程度对银纳米单层膜基底SERS活性的影响. 实验发现该方法制备的银纳米粒子膜的SERS活性与预聚集程度直接相关, 在最优参数下制备的SERS基底具有银颗粒分布均匀、SERS活性均一、增强效果好等优点. 实验分别以罗丹明6G (R6G)、3-巯基丙酸(3MPA)和9-氨基吖啶盐酸盐(9AA)为探针对所制备基底的SERS活性进行了测试, 结果均获得了高信噪比的SERS信号.     

柠檬酸辅助可控制备花状银粒子及其表面增强拉曼散射性能

以抗坏血酸为还原剂,柠檬酸为结构导向剂,一步还原硝酸银,合成了尺寸和形状可调的花状银颗粒。纳米粒子的粒径可在600～1 200 nm范围内调整,表面突起可达到10～25 nm。柠檬酸的化学性质在银纳米粒子合成多级花状银结构的过程中起着至关重要的作用。通过改变柠檬酸或抗坏血酸溶液的用量,银结构的各向异性形貌可以很容易地调节。以制备的多级花状银颗粒作为表面增强拉曼散射(SERS)基底,对浓度为10~(-10)mol·L~(-1)的罗丹明6G(R6G)仍具有较高的检测灵敏度。     

表面增强拉曼光谱法测定牛奶中青霉素G钠的残留量北大核心CSCD

青霉素G钠(NaBP)溶液的常规拉曼光谱信号微弱.将制备的浓缩银纳米粒子(AgNPs)20μL与不同浓度(1×10^(-9)~1×10^(-1)mol·L^(-1))的青霉素G钠溶液(pH 6)20μL混合,所得混合液的表面增强拉曼光谱(SERS)信号显著增强,在上述混合液中加入1×10^(-2)mol􀅰L^(-1)硫酸镁溶液8μL,青霉素G钠SERS增强效果最佳.据此,提出了以AgNPs为基底,硫酸镁为凝聚剂,采用SERS测定青霉素G钠含量的方法,并用于加标牛奶样品的检测.结果表明,青霉素G钠浓度为1×10^(-8)~1×10^(-3)mol·L^(-1)时,其浓度的对数值与相应的SERS信号强度呈线性关系,检出限(3s/k)为8.2×10^(-9)mol·L^(-1).按标准加入法进行回收试验,回收率为80.0%~96.0%,测定值的相对标准偏差(n=5)为2.3%~6.5%.     

Ag纳米粒子在TiO2四棱柱阵列上的可控生长及其SERS效应

采用水热法在导电玻璃FTO导电面上沉积TiO₂四棱柱阵列; 并以其为基体, 分别采用聚乙烯基吡咯 烷酮(PVP)还原Tollens试剂以及柠檬酸三钠(TSC)还原硝酸银溶液, 将Ag纳米粒子(AgNPs)沉积在TiO₂四棱柱阵列上形成TiO₂@AgNPs-PVP和TiO₂@AgNPs-TSC微纳结构作为表面增强拉曼散射(SERS)基底. 实验结果表明, Ag纳米粒子在TiO₂四棱柱阵列上的尺寸和分布可通过改变Tollens试剂的浓度和TSC还原硝酸银溶液的反应时间来调控, 进而优化基底的SERS灵敏度. TiO₂@AgNPs-PVP微纳结构对罗丹明6G(R6G)的检出限为10^-12 mol/L, 对低活性小分子三聚氰胺的检出限为0.01 mg/mL; TiO₂@AgNPs-TSC微纳结构对R6G的检出限为10^-10 mol/L, 对三聚氰胺的检出限为0.01 mg/mL. TiO₂@AgNPs-PVP和TiO₂@AgNPs-TSC微纳结构基底的SERS活性、 循环可回收性与还原剂种类紧密相关: 包覆在Ag纳米粒子上的PVP可以作为隔离层避免Ag纳米粒子直接接触, 防止电磁场耦合作用减弱, 增强基底的SERS活性; 同时, PVP是一种水性聚合物, 有较强的亲水性, 作为循环可回收SERS基底使用时, 吸附小分子物质清洗难度较大.     

三维树枝状银薄膜的可控生长及其在表面增强拉曼光谱中的应用

通过电流置换反应制备了树枝状银纳米薄膜。在反应过程中通过控制反应时间和硝酸银的浓度,得到了不同形貌、分布和密度的树枝状银薄膜,从而得到了具有不同SERS性能的树枝状银纳米薄膜。选取了具有最佳SERS性能的树枝状银纳米薄膜对罗丹明6G进行了微量检测、再现性检测和稳定性检测,其检测限可达到1×10~(-11) mol·L~(-1),具有优良的再现性和良好的稳定性。     

现场制备表面增强拉曼光谱基底法快速检测药片中盐酸阿米洛利的含量

利用加热贴(暖宝贴)作为热源现场合成银溶胶,并用其作为表面增强拉曼光谱(SERS)基底。使用罗丹明6G(R6G)作为探针分子,对合成的银溶胶的SERS性能进行评价。结果显示,银溶胶的制备方法简便、快速,制备时间在15 min内,具有较好的SERS增强效果,且在4 h内具有较好的稳定性。将现合成的银溶胶用于药片中盐酸阿米洛利的SERS检测,在0.8～8 mg/L范围内盐酸阿米洛利的质量浓度与拉曼峰强度有较好的线性相关系,线性方程为:y=1 395ρ-76.40,r~2=0.999 2。检出限(LOD)为0.2 mg/L,其加标回收率为104%～106%,相对标准偏差为0.35%～3.5%。该方法简单快速、稳定性好,为药片中盐酸阿米洛利的快速检测和鉴别提供了新途径。     

银纳米粒子簇的设计、 制备和表面增强拉曼光谱

通过匹配激光光斑直径与胶体微球的尺寸, 设计制备了银纳米粒子的表面增强拉曼散射(SERS)基底, 并将其用于研究单个银纳米粒子簇的表面增强拉曼光谱. 在制备纳米粒子的过程中, 考察了等离子体刻蚀时间与银沉积厚度对“单”银纳米粒子结构与形貌的影响. 将吡啶、 巯基苯和罗丹明R6G作为SERS探针分子, 研究了其SERS效应, 通过荧光共振能量转移(FRET)机理, 实现了染料分子在单银纳米粒子簇上的SERS效应. SERS光谱测试与相关计算结果表明, 单个银纳米粒子簇的拉曼增强因子能够达到约10⁶.     

表面增强拉曼光谱检测联苯胺

采用柠檬酸钠还原法制备了具有表面增强拉曼散射(SERS)活性的银纳米溶胶, 利用透射电子显微镜、 扫描电子显微镜和紫外-可见光谱仪对银纳米溶胶进行了表征. 对水相的联苯胺进行了SERS研究, 并对联苯胺的拉曼谱带进行了归属. 考察了团聚剂氯化镁的浓度对检测的影响, 发现随着氯化镁浓度的变大, SERS信号呈现出先增大后减弱的趋势, 即氯化镁的浓度存在一个最佳值, 此时联苯胺的检测限可达到10^-8 mol/L.     

Ag/Si-NPA基底上共吸附R6G和CV的表面增强拉曼散射

以硅纳米孔柱阵列(Si-NPA)为基底, 采用浸渍沉积技术制备了具有较高表面增强拉曼散射(SERS)活性的Ag/Si-NPA衬底, 并采用扫描电子显微镜和透射电子显微镜对其表面形貌和结构进行了表征. 在此基础上, 选择罗丹明6G(R6G)和结晶紫(CV)2种生物染料分子并采用不同的混合吸附程序对其共吸附状态下的SERS光谱进行了探测. 结果表明, 当2种分子的溶液浓度均为10^-7 mol/L时, 无论采用何种浸渍吸附程序, 其SERS谱中CV的特征拉曼峰都被R6G完全掩盖. 对溶液采用错级配置(R6G和CV的浓度分别为10^-9和10^-7 mol/L)后, 所测SERS谱上获得了分别对应于R6G和CV的分离良好、相对强度匹配、分辨率高的2个SERS特征峰组, 从而有利于简化现实混合探测过程中对SERS特征峰的指认和判断.     

Controllable Electrochemical Synthesis of Silver Dendritic Nanostructures and Their SERS Properties

Ag dendritic nanostructures were synthesized on fluorine-doped tin oxide covered glass sub-strates by the electrodeposition method. Results demonstrate that the size, diameter, crys-tallinity, and branch density of the Ag dendrites can be controlled by the applied potential,the surfactants and the concentration of AgNO₃. Three kinds of typical silver dendrites were applied as substrates of the surface enhanced Raman scattering (SERS) and one of them was able to clearly detect rhodamine 6G concentrations up to 0.1 nmol/L. The differences of the SERS spectra at these Ag dendrites confirmed that the shapes and interparticle spacings have great effect on Raman enhancement, especially the interparticle spacings.     

银/金纳米线阵列表面增强拉曼基底的制备及对孔雀石绿的高灵敏度检测

利用种子介导的软模板生长方法制备了金纳米线(Au NWs)阵列, 通过调节生长温度控制Au NWs阵列的形貌, 最后在经硼氢化钠(NaBH₄)清洗过的Au NWs阵列上化学沉积银纳米颗粒(Ag NPs), 制得银/金纳米线(Ag/Au NWs)阵列作为表面增强拉曼散射(SERS)基底. 选用罗丹明6G(R6G)作为拉曼探针分子测定了Ag/Au NWs阵列的SERS性能. 结果表明, Ag/Au NWs阵列作为SERS基底具有高灵敏度、 优异的信号均匀性和良好的稳定性. 使用Ag/Au NWs阵列对孔雀石绿(MG)检测的检出限可低至1×10^-8 mol/L, 线性范围为 1×10^-8~1×10^-4 mol/L. NaBH₄可以在不影响SERS性能的情况下去除Ag/Au NWs阵列上吸附的分子, 使得 SERS基底可以重复使用. 使用Ag/Au NWs阵列对湖水中的MG进行检测, 得到了可靠的回收率, 证明Ag/Au NWs 阵列在检测环境水体中的孔雀石绿上具有应用潜力.     

Silver Nanostructures on Graphene Oxide as the Substrate for Surface-Enhanced Raman Scattering (SERS)

Nanosized surface-enhanced Raman scattering (SERS) substrates fabricated by the controlled growth of metal nanostructures on water-dispersed two-dimensional nanomaterials can open a new avenue for SERS analysis of liquid samples in biological fields. In this work, regular and uniform Ag nanostructures were grown on the surface of graphene oxide (GO) through a microwave-assisted hydrothermal method. Polyamidoamine (PAMAM) dendrimers were assembled on the surface of GO to form GO/PAMAM templates for growing Ag nanostructures, which are primarily comprised of Ag dimers and trimers. The prepared Ag/GO nanocomposites are highly dispersed and stable in aqueous solution and may be used as substrates for enhanced Raman detection of rhodamine 6?G (R6G) in aqueous solution. This special substrate provides high-performance SERS and suppresses R6G fluorescence in aqueous solution and is promising as a nanosized material for the enhanced Raman detection of liquid samples in biological diagnostics.     

Differential SERS activity of gold and silver nanostructures enabled by adsorbed poly(vinylpyrrolidone)

We report that poly(vinylpyrrolidone) (PVP), a common stabilizer of colloidal dispersions of noble metal nanostructures, has a dramatic effect on their surface-enhanced Raman scattering (SERS) activity and enables highly selective SERS detection of analytes of various type and charge. Nanostructures studied include PVP-stabilized Au-Ag nanoshells synthesized by galvanic exchange reaction of citrate-reduced Ag nanoparticles (NPs), as well as solid citrate-reduced Ag and Au NPs, both before and after stabilization with PVP. All nanostructures were characterized in terms of their size, surface plasmon resonance wavelength, surface charge, and chemical composition. While the SERS activities of the parent citrate-reduced Ag and Au NPs are similar for rhodamine 6G (R6G) and 1,2-bis(4-pyridyl)ethylene (BPE) at various pH values, PVP-stabilized nanostructures demonstrate large differences in SERS enhancement factors (EFs) between these analytes depending on their chemical nature and protonation state. At pH values higher than BPE's pK(a2) of 5.65, where the analyte is largely unprotonated, the PVP-coated Au-Ag nanoshells showed a high SERS EF of >10(8). In contrast, SERS EFs were 10(3)- to 10(5)-fold lower for the protonated form of BPE at lower pH values, or for the usually highly SERS-active cationic R6G. The differential SERS activity of PVP-stabilized nanostructures is a result of discriminatory binding of analytes within-adsorbed PVP monolayer and a subsequent increase of analyte concentration at the nanostructure surface. Our experimental and theoretical quantum chemical calculations show that BPE binding with PVP-stabilized Au-Ag nanoshells is stronger when the analyte is in its unprotonated form as compared to its cationic, protonated form at a lower pH.     

表面增强拉曼试纸的制备及保质性

以滤纸的多级纤维结构为基底, 通过物理气相沉积(PVD)方法蒸镀一定厚度的银膜, 制备了表面增强拉曼试纸, 以罗丹明6G(R6G)为探针分子, 其最低检测限(LOD)可以达到10^-10 mol/L. 采用密闭氮气环境保存可解决银SERS基底使用寿命短的问题, 使得试纸可以长时间保持活性.     

Fabrication of flower-like silver nanoparticles for surface-enhanced Raman scattering

The flower-like silver nanoparticles have been synthesized by reducing silver nitrate (AgNO₃) with ascorbic acid (AA) as the reductant and polyvinyl pyrrolidone (PVP) as the capping agent under vigorous stirring. Such flower-like nanoparticles are aggregates of small nanoplates and nanorods. They were tested as substrates for the surface-enhanced Raman scattering (SERS), showing high sensitivity for detecting Rhodamine 6G (R6G) at a concentration as low as 10^-7 mol/L. It has been found that replacing mechanical stirring with ultrasound sonication would drastically change the particle morphology, from flower-like nanoparticles to well-dispersed smaller nanoparticles. Furthermore, when trace amounts of NaCl were added into the reagents, well-dispersed Ag nanoparticles formed even in vigorous stirring. These phenomena can be explained with the diffusion and reactant supply during nucleation and growth of Ag nanoparticles.     

The ultratrace detection of crystal violet using surface enhanced Raman scattering on colloidal Ag nanoparticles prepared by electrolysis

Highly active,stable and affordable surface enhanced Raman scattering(SERS) substrates were obtained by electrolyzing a mixture of AgNO_3(4×10~(-4) mol/L) and Na_3C_6H_5O_7·H_2O(6×10~(-5) mol/L) for 1,2,3 and 4h at 7V.With crystal violet(CV) as a test molecule,a portable Raman spectrometer with 785 nm laser excitation was employed to carry out the SERS detection.Colloidal Ag nanoparticles prepared by electrolyzing for 3 h with the particle size of(65±17) nm is a perfect SERS substrate for the ultratrace ...     

双金属双硅层核-壳纳米结构Au@SiO2@Ag@SiO2用于葡萄糖检测

制备了一种灵敏度高、 稳定性强的双金属双硅层核-壳结构纳米材料Au@SiO₂@Ag@SiO₂. 由于双金属之间的硅层促进了远程等离子体的激发转移, 使该纳米粒子具有良好的表面增强拉曼散射(SERS)的特性及优异的稳定性. 利用这种SERS活性材料能直接检测出人体尿液的主要成分, 且该材料呈现出对低浓度(10^-6 mol/L)葡萄糖的无标记高效检出能力. 此外, 还实现了人工尿液中等浓度(10^-3 mol/L)葡萄糖和尿素分子的同时检测, 以及实际尿液中10^-3 mol/L葡萄糖的检测. Au@SiO₂@Ag@SiO₂纳米粒子具有在多种生物分子存在时快速检测葡萄糖的实际应用潜力.