College of Food Science and Engineering , Hefei University of Technology , Hefei , Anhui 230009 , China.
Department of Tumor Radiotherapy , The First Affiliated Hospital of Anhui Medical University , Hefei 230022 , China.
Anal Chem. 2018 Apr 17;90(8):5232-5238. doi: 10.1021/acs.analchem.8b00008. Epub 2018 Apr 3.
Liquid-state interfacial nanoparticle arrays for surface-enhanced Raman scattering (SERS) promises a practical, substrate-free, and rapid analysis but faces a great challenge to develop a batch and uniform fabrication strategy with stable internal standards (IS) because of the difficulties in precisely locating both the IS tags and analytes in the same local structure under the harsh conditions of biphasic liquid interface. Here, we develop a fast batch preparation of self-ordered dense Au nanoparticle (GNP) arrays on cyclohexane/water biphasic interface in 96-well plates with the assist of acetone as the phase-crossing inducer. The acetone can extract the pesticide molecules via a simple dipping sample peels and can rapidly capture and locate the pesticide molecule into the plasmonic hotspots. Meanwhile, this phase-crossing solvent, acetone itself, generates stable SERS signal and is used as the IS tags to calibrate the signal fluctuation. This platform presents an excellent uniformity with a relative standard deviation (RSD) of 5.9% compared to the RSD of 14.5% without the IS's correction and a good sensitivity with a limit of detection (LOD) of 1 nM thiram. This high-throughput strategy for analyzing pesticide residues at fruit peels reached detection levels of nanograms per square centimeter (ng/cm). Combined with the 96-well plates, this platform greatly facilitates the self-assembly and multiplex sampling. The self-ordered arrays at two immiscible phases interface evidenced the detection of both the oil-soluble thiabendazole and the water-soluble thiram molecules and also realized the multiplex and two-phase detection of these two pesticides. This platform offers vast possibilities for on-site sensing of various analytes and paves a new way for the quantitative and high-throughput SERS analyzer just as convenient as the microplate reader.
用于表面增强拉曼散射 (SERS) 的液态界面纳米粒子阵列有望实现实用、无基底和快速分析，但由于在两相液体界面苛刻条件下精确定位内标 (IS) 标签和分析物两者于同一局部结构存在困难，因此发展批量且均匀的制造策略具有很大的挑战性。在这里，我们开发了一种在 96 孔板中环己烷/水双相界面上快速批量制备自有序密集金纳米粒子 (GNP) 阵列的方法，该方法借助丙酮作为相转变诱导剂。丙酮可以通过简单的浸渍样品剥离提取农药分子，并能快速捕获和定位农药分子到等离子体热点中。同时，这种相转变溶剂丙酮本身可以产生稳定的 SERS 信号，并用作内标标签来校准信号波动。与不使用内标标签校正时的 14.5%的相对标准偏差 (RSD) 相比，该平台的均匀性非常好，相对标准偏差为 5.9%，具有良好的灵敏度，检测限 (LOD) 为 1 nM 福美双。这种用于分析果皮中农药残留的高通量策略达到了纳克每平方厘米 (ng/cm) 的检测水平。结合 96 孔板，该平台极大地方便了自组装和多重采样。在两个不混溶相界面上的自有序阵列证明了对油溶性噻菌灵和水溶性福美双分子的检测，并且还实现了这两种农药的多重和两相检测。该平台为各种分析物的现场传感提供了广阔的可能性，并为定量和高通量 SERS 分析仪开辟了一条新途径，就像微孔板读器一样方便。
