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81.
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表面增强拉曼光谱快速检测赤藓红   总被引:5,自引:0,他引:5  
赤藓红是一种广泛应用在食品行业的着色剂,由于过量食用对人体健康具有潜在的危害性,赤藓红的每日允许摄入量被严格限制.文中针对赤藓红的理论计算拉曼、普通拉曼以及表面增强拉曼光谱进行了研究.理论计算拉曼采用密度泛函理论(DFT)在B3LYP/6-31 G(d)水平上对赤藓红分子进行了构型优化,赤藓红的实验拉曼光谱与理论计算拉曼对比具有很好的对应性.采用金纳米颗粒作为表面增强拉曼基底,从赤藓红与金胶混合体积比、溶液pH和混合时间对检测条件进行优化,混合体积比为1∶1、pH为5、混合时间为10min时赤藓红溶液的检测限可达到1 μg/mL.研究结果证明以金胶为增强基底的表面增强拉曼光谱法可以快速准确地鉴定赤藓红,为日后检测常规食品样品中的赤藓红提供了基础.  相似文献   
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In this report, we describe a fabrication process of low-cost and highly sensitive SERS substrates by using a simple anodizing setup and a low-energy magnetron sputtering method. The structure of the SERS substrates consists of silver nanoparticles deposited on a layer of anodic aluminum oxide (AAO) template. The fabricated SERS substrates are investigated by a scanning electron microscope (SEM), a transmission electron microscope (TEM), and a confocal Raman spectroscope. We have verified from the surface morphology that the fabricated SERS substrates consist of high-density round-shape silver nanoparticles where their size distribution ranges from 10 to 30 nm on the top and the bottom of nanopores. The surface-enhanced Raman scattering activities of these nanostructures are demonstrated using methylene blue (MB) as probing molecules. The detection limit of 10−8 M can be achieved from this SERS substrate.  相似文献   
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用表面增强拉曼光谱技术(SERS)对在3%NaCl溶液中苯并三氮唑(BTA)及其衍生物4-羟基苯并三氮唑(4CBTA)对铜的缓蚀作用机理进行了研究,发现4CBTA对铜的缓蚀作用机理与BTA相似,在较正电位下两者都是通过三唑环与铜形成配合物覆盖在铜表面随着电位负移,铜电极表面吸附的分子形式的BTA或4CBAT数量增多;4CBT中的-COOH基团只是起到空间位阻的作用,没有参与电极表面的吸附,两者复配使用时以BTA吸附为主,其缓蚀机理没有发生改变。也没有产生协同效应。  相似文献   
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Surface‐enhanced Raman scattering (SERS) provides an approach for the label‐free and miniaturized detection of the trace amount of analyte molecules. A SERS microchip of Au‐areoles array, mimicking the areole on the cactus, is facilely and controllably prepared through selectively electrochemical deposition on patterned superhydrophilic–superhydrophobic substrates. The Au‐areoles are full of SERS hot spots thanks to the large amounts of sharp edges, tips, and coupled branches. Meanwhile, the superhydrophilic sites on the superhydrophobic substrate can collect the target molecules into those hot spots. The combination of the SERS enhancement of the nanostructured‐Au and the collective effect of the superhydrophilic–superhydrophobic pattern endows the microchip with sample‐effective, ultrasensitive, and efficient Raman detection capabilities, which are demonstrated by integrated detection of femtomol Rhodamine 6G and diverse bioanalytes. The chip can also be used for mutually independent multisample detection without interference.  相似文献   
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We present here a simple procedure for the surface modification of plasmonic nanoparticles (NPs) with a cationic water-soluble ammonium pillar[5]arene (AP[5]A) in order to create selective surface-enhanced Raman scattering (SERS) spectroscopy based sensors. The strategy is based on a ligand exchange reaction between the AP[5]A and the stabilizing agent of the as-prepared plasmonic NPs. The approach could be applied to plasmonic nanoparticles either negatively charged, stabilized by citrate ions (Au spheres) or positively charged, stabilized by cetyltrimethylammonium bromide (Au and Au@Ag nanorods). The SERS performance of all systems was studied as a function of NP size and excitation laser line by using an analyte with no affinity towards the metal surface such as pyrene. The analytical enhancement factor (AEF) for the different systems was estimated between 0.55×104 and 1.49×105. Finally the synergistic effect of combining supramolecular chemistry and plasmonic NPs is demonstrated through SERS-based detection, in aqueous media, of molecules with no affinity towards a bare plasmonic substrate such as the contaminant pyrene or the biomolecule pyocyanin with nanomolar limit of detection.  相似文献   
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A preconcentrating surface‐enhanced Raman scattering (SERS) sensor for the analysis of liquid‐soaked tissue, tiny liquid droplets and thin liquid films without the necessity to collect the analyte is reported. The SERS sensor is based on a block‐copolymer membrane containing a spongy‐continuous pore system. The sensor's upper side is an array of porous nanorods having tips functionalized with Au nanoparticles. Capillarity in combination with directional evaporation drives the analyte solution in contact with the flat yet nanoporous underside of the SERS sensor through the continuous nanopore system toward the nanorod tips where non‐volatile components of the analyte solution precipitate at the Au nanoparticles. The nanorod architecture increases the sensor surface in the detection volume and facilitates analyte preconcentration driven by directional solvent evaporation. The model analyte 5,5′‐dithiobis(2‐nitrobenzoic acid) can be detected in a 1 × 10?3m solution ≈300 ms after the sensor is brought into contact with the solution. Moreover, a sensitivity of 0.1 ppm for the detection of the dissolved model analyte is achieved.  相似文献   
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