摘要/Abstract

表面增强拉曼光谱（SERS）因极高的检测灵敏度且能够提供丰富的分子结构信息，可实现原位、实时监测等优点而成为广受关注的痕量分析工具.本文发展了基于微流控和SERS的联用技术，实现了微有机合成反应的现场监测.以磁性核壳纳米粒子Fe₃O₄@Ag为SERS基底，通过外加磁场调控富集实现连续的SERS检测；结合微流控反应器在有机合成中反应物用量少、效率高、易于实现在线检测和高通量筛选的优势，实现了α-苯乙醇的微量合成反应以及实时SERS监测.研究表明，Fe₃O₄@Ag核壳纳米粒子具备在微流控反应通道中的磁富集功能和SERS连续检测的性能.通过改变微流控通道中反应物的流速可调控反应速度，在固定时间内获得不同浓度的反应物，利用差谱技术消除反应物光谱的干扰，获得了产物α-苯乙醇的特征SERS光谱.结果表明微流控技术与SERS联用可发展成为微量有机反应的监测手段，在有机化学反应高通量筛选中具有潜在应用价值.
关键词: 表面增强拉曼光谱, 微流控, 磁性纳米粒子, 在线监测, α-苯乙醇
Surface Enhanced Raman Spectroscopy (SERS) has been developed as one of powerful tools for monitoring the organic reaction due to its extremely high sensitivity. Moreover, SERS provided the abundant fingerprint spectroscopic information for the structure analysis, and it could be integrated with other techniques to achieve the on-line detection. Microfluidic technology, due to its significant role in the miniaturization, integration and portability of instrument, exhibits the promising application in biomedicine, high throughput drug screening, the environment monitoring and protection. In recent years, the microfluidic chip as one of the modern technology for analyzing various substances at the same time has been rapidly developed. Compared with the conventional technique, it has the significant advantage and convenience, such as low reagent consumption, short reaction time, high reaction efficiency and so on. Herein, the microfluidic chip was employed as the microreactor for organic reaction with the ultralow dosage, and the SERS detection was integrated into the microreactor to realize the continuous monitoring on the substrates and products. The magnetic core-shell nanoparticles Fe₃O₄@Ag acted as the SERS substrate with reasonable magnetism and SERS activities, and it demonstrated that the magnetic nanoparticles was flowed in the microchannel of microfluidic chip and was enriched by the external magnetic field. The introduction of magnetic nanoparticles is beneficial to improve the detection sensitivity by the magnetic aggregation and to reach the continuous SERS detection by applying and retracting external magnetic field. At the same time, it exhibited the significant advantages of low amount of reactants, high efficiency and easy to realize on-line detection and high throughput screening in organic synthesis. The micro-synthesis of α-phenylethanol and the real-time monitoring of SERS are performed by the alternative enrichment and de-enrichment of magnetic nanoparticles in the present case. By changing the flow rate of reactants in the channel of microfluidic chip, different concentrations of reactants and products were obtained in a certain duration. The influence of the spectral features from the reactants was eliminated by differential spectrum technique, and the distinctive SERS spectrum of α-phenylethanol was presented accordingly. It demonstrated that the integration of microfluidic chip and SERS technique could be developed as a powerful tool for on-line monitoring organic reactions and exhibits the promising application in high throughput screening of organic chemical reactions.
Key words: surface enhanced Raman spectroscopy (SERS), microfluidic, magnetic nanoparticles, on-line detection, α-phenylethanol


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