树枝状银微纳结构的表面增强拉曼散射效应研究

利用两电极电化学沉积法制备出一种树枝状银微纳结构基体.扫描电子显微镜(SEM)的表征结果证实所制备的银基体呈现出完整的树枝状结构,具有对称性的树枝和树干,且树叶清晰可见.实验结果表明,树枝状银微纳结构的表面增强拉曼散射(Surface-enhanced Raman scattering,SERS)可以检测到超低浓度的罗丹明6G(Rhodamine 6G,R6G,10-10 mol/L)光谱信号,即树枝状银微纳结构作为SERS基体表现出较好的灵敏性;当R6G的浓度在10-5~10-10 mol/L范围依次降低一个数量级时,谱带610 cm-1处的拉曼散射强度的相对标准偏差分别为12.1%,12.0%,11.7%,10.9%,13.2%和14.3%,表明所制备银基体的SERS"热点"(Hot spots)分布较均一,树枝状银微纳结构作为SERS基体具有较好的重现性;当低SERS活性的3-巯基丙酸(3-Mercaptopropionic acid,3MPA)的检测浓度为10-5 mol/L时,利用树枝状银基体能检测到3MPA的SERS光谱,说明所制备的银基体对低活性物质也具有较好的SERS灵敏性.     

运用金-银核壳结构纳米棒的表面增强拉曼效应检测超痕量葡萄糖

运用种子生长法合成金纳米棒溶胶,再经过化学还原法合成金-银核壳纳米棒溶胶作为表面增强拉曼活性基底。该基底可以检测低至10-18mol/L的罗丹明6G,其增强因子高达1011,具有优异的SERS增强效果。利用此基底的表面增强拉曼散射效应检测10-14~10-8mol/L的葡萄糖,并得到表面增强拉曼信号强度与相应葡萄糖浓度的工作曲线。实验结果表明,该基底在葡萄糖的检测及半定量分析方面具有良好的潜在应用前景。     

Crystallinity engineering of Au nanoparticles on graphene for in situ SERS monitoring of Fenton-like reaction

Fabrication of multifunctional nanoplatform to in situ monitor Fenton reaction is of vital importance to probe the underlying reaction process and design high-performance catalyst.Herein,a hybrid catalyst comprising of single-crystalline Au nanoparticles（SC Au NPs） on reduced graphene oxide（RGO） sheet was prepared,which not only exhibited an excellent ¹ O₂ mediated Fenton-like catalytic activity in promoting rhodamine 6 G（R6 G） degradation by activating H₂ O_...     

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.     

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.     

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.     

纳米银修饰的超疏水界面用于农药的超灵敏检测

采用化学还原法,在具有不同微观结构的规整的不锈钢网和聚纤维素酯薄膜表面合成了银纳米颗粒.利用氟化试剂对复合界面进行处理,形成超疏水性能的界面,能有效地浓缩目标分子.以罗丹明6G(R 6G)为分析物,纳米银修饰聚纤维素酯薄膜为基底,采用表面增强拉曼散射(SERS)分析了氟化处理前后基底对目标分子的检测能力.实验结果表明,具有超疏水性能的复合基底对R 6G分子的检出限为1 ×10-16 mol/L.以纳米银修饰的不锈钢网和聚纤维素酯两种复合材料为基底,对常用杀虫剂敌百虫的检出限分别为1×10-15 mol/L和1×10-16 mol/L.     

二步电沉积法制备Au/氧化石墨烯复合薄膜作为SERS基底

采用二步电沉积方法在Ti片表面制备了Au-氧化石墨烯（Au-GO）复合薄膜,通过XRD、SEM、XPS等对薄膜的组成、结构和形貌进行了表征,并以罗丹明6G（R6G）为探针分子,对Au-GO/Ti基底的SERS活性进行了表征。结果显示,Au纳米颗粒尺寸约为60 nm,均匀、致密分布于GO表面,该基底显示出较高的SERS活性,对R6G分子的检测极限可达~10^-10 mol·L^-1,增强因子高达约10⁶,且基底显示出良好的稳定性,在冰箱中存放90 d后,SERS活性仅降低30%左右。     

二步电沉积法制备Au/氧化石墨烯复合薄膜作为SERS基底

采用二步电沉积方法在Ti片表面制备了Au-氧化石墨烯（Au-GO）复合薄膜,通过XRD、SEM、XPS等对薄膜的组成、结构和形貌进行了表征,并以罗丹明6G（R6G）为探针分子,对Au-GO/Ti基底的SERS活性进行了表征。结果显示,Au纳米颗粒尺寸约为60 nm,均匀、致密分布于GO表面,该基底显示出较高的SERS活性,对R6G分子的检测极限可达~10^-10 mol·L^-1,增强因子高达约10⁶,且基底显示出良好的稳定性,在冰箱中存放90 d后,SERS活性仅降低30%左右。     

Strategy for obtaining improved surface-enhanced Raman scattering by combining electrochemical and plasmas technologies

In this work, surface-enhanced Raman scattering (SERS)-active gold substrates were first developed by combining the technologies of oxidation–reduction cycles (ORCs) and plasmas treatments in roughening metal substrates. First, a gold substrate was treated by argon plasmas. Then the treated gold substrate was further roughened by triangular-wave ORCs in an aqueous solution containing 0.1 M HCl. Encouragingly, the SERS of Rhodamine 6G (R6G) adsorbed on this roughened gold substrate modified by argon plasmas pretreatment exhibits a higher intensity by 10-fold of magnitude and a better resolution, as compared with the SERS of R6G adsorbed on an unmodified roughened gold substrate. Meanwhile, the probing concentration of R6G adsorbed on the modified substrate can be reduced by one order. It was also found that the pretreatment of argon plasmas demonstrates a positive effect on the (2 2 0) face of Au partly changing into the (1 1 1) face with the lowest surface energy after the ORCs roughening, which is contributive to the improved SERS observed.     

复合纳米材料Cu2O@Au对水体中罗丹明B的检测应用研究

制备了多面体Cu2 O纳米粒子,利用Cu2 O的还原性,在其表面原位生成了不同密度的Au纳米粒子,制备了Au、Cu共同增强拉曼信号的复合纳米粒子Cu2 O@Au.利用透射电镜(TEM)、扫描电镜(SEM)、X射线衍射(XRD)等对制备的Cu2 O和Cu2 O@Au的形貌、粒径、表面性能等进行了表征.研究了Cu2 O表面金纳米粒子的分布密度对水样中目标检测物罗丹明B的拉曼增强效果.结果表明,氯金酸浓度在1 mmol/L时制备的Cu2 O@Au表面均匀覆盖一层金纳米粒子,其表面增强拉曼效果最为显著,对水样中罗丹明B检测范围为1×10-2~5×10-6 mol/L.研究了此探针在PBS(1×)和酸性水溶液(0.01 mol/L HCl)中的稳定性,并将其用于沂河水样中靶标的检测实验,结果表明,其稳定性较好.     

Trace molecules detectable by surface-enhanced Raman scattering based on newly developed Ag and Au nanoparticles-containing substrates

In this work, Ag and Au nanoparticles-containing substrates were first developed for obtaining a stronger surface-enhanced Raman scattering (SERS) intensity of Rhodamine 6G (R6G) and reducing the limit of detection (LOD) of trace molecules. First, the optimum electrochemically roughening conditions employed on Ag substrates for obtaining strongest SERS of R6G were investigated. Then the optimally roughened Ag substrates were incubated in the prepared Cl- and Au-containing solutions for different couples of minutes to undergo the galvanic replacement reactions. Encouragingly, the SERS of R6G adsorbed on this roughened Ag substrate modified by the replacement of Ag with Au for 5 min exhibits a higher intensity by 8-fold of magnitude, as compared with the SERS of R6G adsorbed on an unmodified roughened Ag substrate. Moreover, the practical LOD of R6G can be reduced by one order of magnitude from 1 ppq to 0.1 ppq. Further investigations indicate that the compositions of complexes formed on the substrates demonstrate decided effects on the improved SERS.     

The surface-enhanced Raman spectra of aflatoxins: spectral analysis, density functional theory calculation, detection and differentiation

High-quality surface-enhanced Raman scattering (SERS) spectra of aflatoxin (AF) B(1), B(2), G(1) and G(2) have been acquired using silver nanorod (AgNR) array substrates fabricated by oblique angle deposition method. Significant vibrational peaks are identified on the argon plasma-cleaned substrates, and those peaks agree very well with the Raman spectra calculated by density function theory (DFT). The concentration-dependent SERS detection is also explored. The relationship between the concentration (C) of different AFs and the SERS intensity (I) of the Raman peak at Δν = 1592 cm(-1) is found to follow the general relationship I = AC(α), with α ranging from 0.32 to 0.46 for the four AFs. The limits of detection (LODs) reach 5 × 10(-5) mol L(-1) for AFB(1), 1 × 10(-4) mol L(-1) for AFB(2), and 5 × 10(-6) mol L(-1) for both AFG(1) and AFG(2) in bulk solution, or 6.17 × 10(-16) mol/1.93 × 10(-4) ng of AFB(1), 1.23 × 10(-15) mol/3.88 × 10(-4) ng for AFB(2), 6.17 × 10(-17) mol/2.03 × 10(-5) ng for AFG(1), and 6.17 × 10(-17) mol/2.04 × 10(-5) ng for AFG(2) per laser spot. Principal component analysis (PCA) is used to successfully differentiate these four different kinds of AFs at different concentrations up to their detection limits. The LODs obtained from PCA agree with the LODs obtained by using peak fitting method. With such a low detection limit and outstanding differentiation ability, we prove the possibility of utilizing the SERS detection system as a platform for highly sensitive mycotoxin detection.     

双硫腙螯合形成树脂分离富集地质样品中的微量金,铂,钯及其测定

研究了双硫腙螯合形成树脂的合成及其分离富集地质样中Ａｕ，Ｐｔ，Ｐｄ的条件。于ｐＨ１．５的ＨＣｌ介质中，Ａｕ，Ｐｔ，Ｐｄ定量吸附于Ｈ２ＤＺ形成树脂上与大量贱金属分离。用０．６ｍｏｌ／Ｌ的硫脲－０．１ｍｏｌ／ＬＨＣｌ洗脱贵金属，回收率均在９４％－１０６％之间。铁也部分上柱，用磺基水杨酸与酒石酸１：１联合掩蔽除去。     

Silver overlayer-modified surface-enhanced Raman scattering-active gold substrates for potential applications in trace detection of biochemical species

Because Ag and Au nanoparticles (NPs) possess well-defined localized surface plasmon resonance (LSPR) they are popularly employed in the studies of surface-enhanced Raman scattering (SERS). As shown in the literature and in our previous studies, the advantage of SERS-active Ag NPs is their higher SERS enhancement over Au NPs. On the other hand, the disadvantage of SERS-active Ag NPs compared to Au NPs is their serious decay of SERS enhancement in ambient laboratory air. In this work, we develop a new strategy for preparing highly SERS-active Ag NPs deposited on a roughened Au substrate. This strategy is derived from the modification of electrochemical underpotential deposition (UPD) of metals. The coverage of Ag NPs on the roughened Au substrate can be as high as 0.95. Experimental results indicate that the SERS of Rhodamine 6G (R6G) observed on this developed substrate exhibits a higher intensity by ca. 50-fold of magnitude, as compared with that of R6G observed on the substrate without the deposition of Ag NPs. The limit of detection (LOD) for R6G measured on this substrate is markedly reduced to 2 × 10⁻¹⁵ M. Moreover, aging of SERS effect observed on this developed substrate is significantly depressed, as compared with that observed on a generally prepared SERS-active Ag substrate. These aging tests were performed in an atmosphere of 50% relative humidity (RH) and 20% (v/v) O₂ at 30 °C for 60 day. Also, the developed SERS-active substrate enables it practically applicable in the trace detection of monosodium urate (MSU)-containing solution in gouty arthritis without a further purification process.     

Effects of electrolytes used in roughening gold substrates by oxidation–reduction cycles on surface-enhanced Raman scattering

In this work, the effects of electrolytes used in roughening gold substrates by electrochemical methods on surface-enhanced Raman scattering (SERS) were first investigated. First, gold substrates were roughened by triangular-wave oxidation–reduction cycles (ORC) in aqueous solutions containing different kinds of 0.1 M electrolytes. Then Rhodamine 6G (R6G) was used as Raman probe to examine this effect of electrolytes used on the SERS observed. The result indicates that the highest intensity of SERS of R6G was obtained on the roughened Au substrate prepared in 0.1 M NaCl, which was less used in the literature. Meanwhile, it was also found that the rougher surface morphology observed, which is contributive to the higher SERS obtained, is corresponding to the smaller cathodic peak area shown in the cyclic voltammograms for roughening the Au substrate.     

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.     

Colloidal AgCl induced-growth of thorny gold nanoparticles and their SERS activity

In this paper, we exploited a unique procedure for obtaining thorny gold nanoparticles (Au NPs) with controllable length of thorns without using seeds and surfactants. The obtained Au NPs exhibited shape-determined surface-enhanced Raman spectroscopy activity toward rhodamine 6G.     

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.     

维生素B6在纳米金/石墨烯修饰电极上的电化学行为

将金纳米粒子电沉积在石墨烯修饰的玻碳电极表面,研究了维生素B6(VB6)在该修饰电极上的电化学行为。扫描电镜用于该修饰电极组装过程的形貌表征。实验结果表明:VB6在此修饰电极上出现一个良好的氧化峰,在最佳实验条件下,其氧化峰电流与VB6浓度在5.0×10-8～2.0×10-5 mol/L范围内呈线性关系,其线性回归方程为I(μA)=0.5697c(μmol/L)+0.06275,R=0.9992,检出限为2.0×10-8 mol/L(S/N=3)。一些常见的干扰物质如抗坏血酸不干扰VB6的检测。方法已用于片剂中VB6的含量的检测。