三维仿生柔性SERS基底构建及其用于果蔬表皮农药残留检测

发布时间：2018-03-05 14:20

本文选题：表面增强拉曼光谱　切入点：柔性SERS基底　出处：《华中农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：表面增强拉曼光谱(SERS)技术是一种高灵敏的分析工具,以其独具的谱带窄、抗光漂白、无水干扰、取样量小、原位无损以及提供指纹图谱信息等优势广泛地应用于公共安全、食品安全、环境监测、生命科学等领域。创制一种可用于现场样品快速高效采集,并直接检测的SERS基底一直是表面增强拉曼光谱领域研究的热点和关键。近年来,柔性基底因更加满足实用化基底的诸多需求而备受瞩目。然而,目前的柔性SERS基底大都是以纤维滤纸、胶布、石墨烯等为衬底,信号的增强效果和重现性都难以令人满意。此外,得到的基底表面不具有三维(3D)的纳米结构,这严重限制了它对表面残留样品的采集效率。这使得柔性SERS基底在实用化的过程中面临着不小的挑战。基于以上背景及现状,本文致力于发展柔性材料与仿生学相结合的制备SERS基底的新方法;构建使用方便,可用于现场直接快速采样检测的,灵敏度高,重现性好,稳定性强的3D仿壁虎脚的纳米“触角”SERS新基底(G-SERS);并将其应用于果蔬表皮农药残留的快速、高效采集和非标记、无损检测;具体研究内容如下:1.采用表面超疏水处理的有序阳极氧化铝(AAO)为模板,聚二甲基硅氧烷(PDMS)为注塑材料旋涂于AAO表面,加热成型后物理剥离得到高密度类壁虎脚的3D纳米“触角”阵列。这些有序的“触角”结构能够为SERS活性纳米粒子在不同维度的沉积提供高密度的支架。在此基础上利用种子沉积法将银纳米粒子修饰到“触角”阵列上,经时间优化,产生了大面积的“热点”区域,制备出3D结构的仿生基底。本章中我们研究了不同类型阳极氧化铝的脱模效果,优化了银纳米粒子沉积时间并对基底的各项SERS性能进行了表征。这种新型仿生基底使用方便,不仅拥有出众的SERS活性(IF=1.2×107),优越的重现性(RSD=5.8%)和出色的稳定性还具有众多柔软灵活的纳米“触角”(6.7×108/cm~2)。2.利用SERS基底表面高密度的3D纳米“触角”,采用直接“粘贴-揭起”的方法,对黄瓜、苹果和葡萄表面的甲基对硫磷、福美双、孔雀石绿残留以及它们的混合物进行快速采样检测。与传统的柔性SERS基底相比,G-SERS基底表面拥有高密度灵活的纳米“触角”,这些“触角”能够像壁虎脚底的刚毛一样能够自由地到达实际样品表面的微区域,通过简单的“粘贴-揭起”对复杂表面的微量样品进行原位、无损地直接收集,并实现现场检测。本章研究了上述三种果蔬表面甲基对硫磷、福美双、孔雀石绿各自的检出限,考察了基底对果蔬表皮农药残留的采集效率,检测结果的重现性以及稳定性。研究发现G-SERS基底对福美双、孔雀石绿、甲基对硫磷的检测限分别达到1.6 ng/cm~2、0.4 ng/cm~2、25 ng/cm~2,在已完成样品采集的果皮表面并没有再检出农药残留,且基底在实际应用中表现出较好的重复性(RSD=9.3%)和稳定性。以上结果表明G-SERS基底在食品安全领域具有巨大的应用前景。
[Abstract]:Surface enhanced Raman spectroscopy (SERS) technology is a high sensitive analysis tool, with its unique narrow bands, resistance to photobleaching, no interference, little sampling, and in situ nondestructive fingerprint information and other advantages are widely used in public safety, food safety, environmental monitoring, life sciences and other fields of creation. A can be used for fast and efficient collection of field samples, and the direct detection of SERS substrate has been a hot and key research on the surface enhanced Raman spectrum field. In recent years, because of the more flexible substrates to meet the needs of many practical base has attracted attention. However, most of the current flexible SERS substrate with fiber filter paper, adhesive tape, graphite substrate as the signal enhancement effect of graphene, and reproducibility are not satisfactory. In addition, the surface of the substrate are not with three-dimensional (3D) nano structure, which seriously limits its surface residual sample collection. This makes SERS flexible rate. In the practical process of substrate in a challenge. The above background and based on the current situation, this paper is a new preparation method of SERS base on the development of flexible material and bionics combination; the construction is convenient to use, can be used directly in the field of fast sampling detection, high sensitivity and reproducibility. Well, the strong stability of 3D nano imitation house lizard foot tentacles SERS base (G-SERS); and its application in fruit and vegetable residues on the surface of the fast, efficient acquisition and non marking, nondestructive testing; the specific contents are as follows: 1. using ordered anodic alumina super hydrophobic surface treatment (AAO) as template, poly two methyl siloxane (PDMS) for injection molding material spin coated on the surface of AAO, heating after forming physical stripping 3D nano "high density house lizard foot antenna array. These" orderly "tentacles" structure to the activity of SERS nanoparticles in The deposition of different dimensions provide support with high density. On the basis of the seed deposition of silver nanoparticles were modified to the "tentacles" array, the optimization time, produced a large area of the "hot spots", prepared by the biomimetic substrate 3D structure. In this chapter, we study the effect of different types of anodic alumina stripping the optimization of the silver nanoparticles and the deposition time on the performance of SERS substrate were investigated. The new bionic base is easy to use, not only has the SERS activity of superior (IF=1.2 * 107), good reproducibility and stability (RSD=5.8%) color also has many nano flexible antennae "(6.7 x 108/cm~2.2.) the use of 3D nano SERS substrate with high density of tentacles, using direct" paste - lift "method of cucumber, apple and grape surface with methyl parathion, thiram, malachite green residue and A mixture of fast sampling. Compared with the traditional flexible SERS substrate, G-SERS substrate with nano "high density flexible tentacles, the tentacles can be like house lizard foot setae can freely reach the micro regional actual sample surface, in the micro sample complex surface through a simple" paste ", without a direct lift collection, and realize the scene detection. This chapter studies the above three kinds of vegetable surface methyl parathion, thiram, malachite green, their detection limits were investigated base on fruit and vegetable residues on the surface of collection efficiency, reproducibility and stability test results. The study found that the G-SERS substrate of thiram. Malachite green, methyl parathion detection reached 1.6 ng/cm~2,0.4 ng/cm~2,25 ng/cm~2 respectively, the pericarp surface has completed the sample collection and no detection of pesticides Residue and substrate have good reproducibility (RSD=9.3%) and stability in practical application. The above results show that G-SERS substrate has great application potential in food safety field.

【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.37;TS255.7

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