School of Chemical and Environmental Engineering , Shanghai Institute of Technology , 100 Haiquan Road , Shanghai 201418 , P.R. China.
Shanghai Fire Research Institute of MEM , 918 Minjing Road , Shanghai 200438 , P.R. China.
Anal Chem. 2019 Sep 3;91(17):11192-11199. doi: 10.1021/acs.analchem.9b02106. Epub 2019 Aug 20.
Development of flexible surface-enhanced Raman spectroscopy (SERS) substrate with controllable "hot spots" has spurred increasing interest because of its unique structure and plasmonic properties. Here, charged poly(vinyl alcohol) microgels containing silver nanoparticles are developed by using microfluidic emulsification to produce a "smart" SERS sensor with charge screening and signals amplification. Importantly, this charged microgel enables the selective concentration of counter-charged molecules and induces the formation of assembled arrays at an immiscible liquid-liquid interface because of the electrostatic interaction. The SERS-active microgels arrays possess controllable structures and facilitate on-site determination of charged pesticides with an enhancement factor of 5.0 × 10. Such nanostructures present the ease of assembly, stability, and reproducibility which allow multiplex detection of analytes at aqueous and organic phases without any pretreatment of the complex matrix samples. The interfacial sensing platform for on-site SERS analysis of charged pesticides will open vast possibilities for a wide range of in-field applications.
发展具有可控“热点”的柔性表面增强拉曼光谱（SERS）基底，由于其独特的结构和等离子体特性，引起了越来越多的兴趣。在这里，通过使用微流控乳液法制备了带负电荷的含有银纳米粒子的聚乙烯醇微凝胶，从而产生了一种具有电荷屏蔽和信号放大功能的“智能”SERS 传感器。重要的是，由于静电相互作用，带负电荷的微凝胶能够选择性地浓缩带相反电荷的分子，并在不混溶的液-液界面诱导组装阵列的形成。SERS 活性微凝胶阵列具有可控的结构，有利于在现场对带电荷的农药进行测定，增强因子为 5.0×10。这种纳米结构具有易于组装、稳定性和重现性，允许在水相和有机相无需对复杂基质样品进行任何预处理的情况下对分析物进行多重检测。用于现场 SERS 分析带电荷农药的界面传感平台将为广泛的现场应用开辟广阔的可能性。
