基于过滤器的表面增强拉曼光谱检测方法的化学污染物快速检测
Summary
一种用于制造和执行增强拉曼光谱（SERS）法检测化学污染物（如农药福美铁和氨苄青霉素）的基于过滤器表面的程序提出。
Abstract
We demonstrate a method to fabricate highly sensitive surface-enhanced Raman spectroscopic (SERS) substrates using a filter syringe system that can be applied to the detection of various chemical contaminants. Silver nanoparticles (Ag NPs) are synthesized via reduction of silver nitrate by sodium citrate. Then the NPs are aggregated by sodium chloride to form nanoclusters that could be trapped in the pores of the filter membrane. A syringe is connected to the filter holder, with a filter membrane inside. By loading the nanoclusters into the syringe and passing through the membrane, the liquid goes through the membrane but not the nanoclusters, forming a SERS-active membrane. When testing the analyte, the liquid sample is loaded into the syringe and flowed through the Ag NPs coated membrane. The analyte binds and concentrates on the Ag NPs coated membrane. Then the membrane is detached from the filter holder, air dried and measured by a Raman instrument. Here we present the study of the volume effect of Ag NPs and sample on the detection sensitivity as well as the detection of 10 ppb ferbam and 1 ppm ampicillin using the developed assay.
Introduction
表面增强拉曼光谱（SERS）是拉曼光谱与纳米技术相结合的技术。在贵金属的金属纳米表面分析物的拉曼散射的强度是由局域型表面等离子体共振大大增强。1银纳米颗粒（银纳米颗粒）是目前最广泛使用的SERS衬底 ，由于其高的增强能力。2截止到目前，银纳米颗粒的各种合成方法已被开发出来。3-6的Ag纳米颗粒可单独使用作为有效的SERS衬底 ，或与其它材料和结构组合，以提高其敏感性和/或功能性。7-11
SERS技术已经证明用于检测食品和环境样品的各种微量污染物的容量大12传统上，存在用于制备SERS样品两种常用方法：溶液和基于基片的方法13的 基于溶液的方法具D使用NP胶体与样品混合。然后将NP-分析物复合使用离心收集，并沉积到干燥后的拉曼测定的固体载体上。基于基板的方法，通常是通过沉积液体试样的数微升到预制固体基材施加14然而，无论是这两种方法都是大量的样品体积的有效和适用的。所述SERS测定的几种修饰克服了体积限制，例如作为集成过滤器系统15-21的或微流体装置的掺入21-24的改性SERS测定表明，在灵敏度和可行性极大增强用于监测化学污染物在大型水样。
在这里，我们证明制造和注射过滤器基于SERS方法的应用程序的详细的协议来检测农药福美铁和抗生素氨苄青霉素的微量。
Protocol
Representative Results
Discussion
其中一个在这个协议中的关键步骤是银纳米粒子合成，其中统一银纳米粒子是一致的结果的关键。加热时间和前体的浓度必须被精确地控制。此AGNPS制备的平均粒径为80纳米，它是由激光粒度仪测得的（数据未显示）。另一个关键步骤是该盐聚合，其中盐的浓度和聚合时间必须精确地控制。此外，膜的选择也是关键的，因为具有较小的孔径的膜被发现更有效的捕集的Ag纳米团簇。在这项研究中所用?…
Divulgations
The authors have nothing to disclose.
Acknowledgements
This material is based upon work supported by the U.S. Department of Homeland Security under Grant Award Number 2010-ST-061-FD0001 through a grant awarded by the National Center for Food Protection and Defense at the University of Minnesota. Disclaimer: The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of Homeland Security or the National Center for Food Protection and Defense.
Materials
| Ampicillin | Fisher Scientific | BP1760-5 | N/A |
| Ferbam | Chem Service | N-11970-250MG | 98+% |
| Silver nitrate | Sigma Aldrich | 209139 | 99.0+% |
| Sodium citrate dehydrate | Sigma Aldrich | W302600 | 99+% |
| Sodium chloride | Sigma Aldrich | S7653 | 99.5+% |
| EMD Millipore Durapore PVDF Membrane Filters | Fisher Scientific | VVLP01300 | 0.10 µm Pore Size, hydrophilic |
| Polycarbonate Filter Holders | Cole-Parmer | EW-29550-40 | 13 mm diameter |
| Analog Vortex Mixer | Fisher Scientific | 02-215-365 | N/A |
| Nutating Mixers | Fisher Scientific | 05-450-213 | N/A |
| DXR Raman spectroscope | Thermo Scientific | IQLAADGABFFAHCMAPB | Laser power: 1 mW Exposure time: 5 s |
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