Ministry of Defence Abbey Wood, Bristol, United Kingdom.
School of Chemical and Bioprocess Engineering, University College Dublin, Dublin, Ireland.
PLoS One. 2019 Nov 25;14(11):e0224492. doi: 10.1371/journal.pone.0224492. eCollection 2019.
Microfluidic reactionware allows small volumes of reagents to be utilized for highly controlled flow chemistry applications. By integrating these microreactors with onboard analytical systems, the devices change from passive ones to active ones, increasing their functionality and usefulness. A pressing application for these active microreactors is the monitoring of reaction progress and intermediaries with respect to time, shedding light on important information about these real-time synthetic processes.
In this multi-disciplinary study the objective was to utilise advanced digital fabrication to research metallic, active microreactors with integrated fibre optics for reaction progress monitoring of solvent based liquids, incompatible with previously researched polymer devices, in combination with on-board Ultraviolet-visible spectroscopy for real-time reaction monitoring.
A solid-state, metal-based additive manufactured system (Ultrasonic Additive Manufacturing) combined with focussed ion beam milling, that permitted the accurate embedment of delicate sensory elements directly at the point of need within aluminium layers, was researched as a method to create active, metallic, flow reactors with on-board sensing. This outcome was then used to characterise and correctly identify concentrations of UV-active water-soluble B-vitamin nicotinamide and fluorescein. A dilution series was formed from 0.01-1.75 mM; which was pumped through the research device and monitored using UV-vis spectroscopy.
The results uniquely showed the in-situ ion milling of ultrasonically embedded optical fibres resulted in a metallic microfluidic reaction and monitoring device capable of measuring solvent solutions from 18 μM to 18 mM of nicotinamide and fluorescein, in real time. This level of accuracy highlights that the researched device and methods are capable of real-time spectrographic analysis of a range of chemical reactions outside of those possible with polymer devices.
微流控反应器件可用于控制微量试剂的流动化学应用。通过将这些微反应器与板载分析系统集成，这些设备从被动式变为主动式，增加了其功能和实用性。这些主动式微反应器的一个紧迫应用是监测反应进度和中间体随时间的变化，从而揭示有关这些实时合成过程的重要信息。
在这项多学科研究中，目的是利用先进的数字制造技术，研究具有集成光纤的金属活性微反应器，用于监测溶剂基液体的反应进度，这些液体与之前研究的聚合物器件不兼容，同时结合板载紫外可见光谱进行实时反应监测。
采用固态、金属基增材制造系统（超声增材制造）结合聚焦离子束铣削技术，可在铝层内直接精确嵌入敏感元件，研究了一种在活性、金属、带有板载传感的流动反应器中创建嵌入式传感元件的方法。然后，将该结果用于表征和正确识别 UV 活性水溶性维生素 B 烟酰胺和荧光素的浓度。从 0.01-1.75mM 形成稀释系列，通过研究装置泵送并使用紫外可见光谱监测。
结果独特地表明，超声嵌入式光纤的原位离子铣削导致能够实时测量烟酰胺和荧光素溶剂溶液从 18 μM 到 18mM 的金属微流控反应和监测装置。这种精度水平表明，研究的设备和方法能够实时进行一系列超出聚合物器件可能范围的化学反应的光谱分析。
