QuSENS Laboratory, Department of Chemical Engineering, Queen's University, Kingston, ON K7L 3N6, Canada.
Analyst. 2020 Jul 7;145(13):4467-4476. doi: 10.1039/d0an00484g. Epub 2020 May 10.
Using a handheld Raman spectrometer, we demonstrate how silver nanodendritic substrates formed on microelectrode platforms can be used for ultrasensitive detection of target analytes, such as cocaine and melamine. The nanostructured substrates are formed through the electrochemical deposition of silver on electrically insulated silicon substrates with the aid of an alternating current (AC) signal applied to the microelectrodes. A nanostructure lateral growth rate of 8.90 ± 0.19 μm min was achieved by implementing a semi-batch process that kept the reactant concentrations high during silver deposition. This facile process can be used with different microelectrode designs, thus allowing for customizable SERS substrates. Compared with a commercially available benchmark, our surface-enhanced Raman scattering (SERS) substrates were found to be at least twice more sensitive. Moreover, by applying multivariate analysis, specifically principal component analysis and linear classification models, the pesticide thiram was identified at 1 ppm with 100% accuracy in spiked apple juice without sample pre-processing. Our technique provides the means for combining microelectrode platforms with SERS for portable, point-of-care sensing applications.
我们使用手持式拉曼光谱仪演示了如何在微电极平台上形成银纳米树枝状基底，以实现对可卡因和三聚氰胺等目标分析物的超灵敏检测。通过在施加到微电极的交流 (AC) 信号的辅助下，将银电化学沉积在电绝缘的硅衬底上，形成纳米结构基底。通过实施半分批工艺，在银沉积过程中保持反应物浓度高，实现了 8.90±0.19 μm min 的纳米结构横向生长速率。这种简单的工艺可以与不同的微电极设计一起使用，从而允许定制 SERS 基底。与市售的基准相比，我们的表面增强拉曼散射 (SERS) 基底的灵敏度至少高出两倍。此外，通过应用多元分析，特别是主成分分析和线性分类模型，无需样品预处理，即可在掺杂的苹果汁中将农药福美双以 1 ppm 的浓度准确识别，准确率为 100%。我们的技术为将微电极平台与 SERS 结合用于便携式现场传感应用提供了手段。
