Microchemical single droplet reaction analysis by online cavity ring-down spectroscopy
Lead Research Organisation:
Imperial College London
Department Name: Chemical Engineering
Abstract
Microfluidics provides an exceptional environment for the generation of controlled droplet dispersions and their manipulation in prescribed flow fields. The spatio-temporal correspondence between microchannel position and reaction 'time' permits the study of kinetics of (chemical and physical) processes with unprecedented time resolution and dynamic range. Further, the combination of the small volumes of droplet 'reactors' and the precise formulation of their composition opens vast possibilities in chemical synthesis, including screening, discovery and optimisation. Monitoring reactions in real-time with non-invasive probes remains, hitherto, a major shortcoming of microchemical reactors due to the minute sample volumes (pL-nL) and fast travel speeds (1-1000 mm/s). This proposal seeks to develop, implement and validate a novel experimental approach to monitor microchemical reactions in real-time by coupling, for the first time, cavity ring-down spectroscopy and solvent-resistant microfabrication. This approach will permit the online study of model catalytic reactions, with unprecedented reproducibility and flow control. Cavity ring-down spectroscopy will permit the analysis of pL volumes, effectively eliminating the restriction of path length in microchannels, with nanosecond to microsecond time resolution, compatible with microreaction drops. In particular, we will elucidate individual and global reaction population outcomes and the effect of mixing and flow, with spatiotemporal resolution. This approach is applicable to a range of organic chemical reactions and, for this work, we will focus on selected model systems (detailed below) of fundamental and industrial relevance.
Publications
James D
(2012)
High-sensitivity online detection for microfluidics via cavity ringdown spectroscopy
in RSC Advances
Lopez CG
(2015)
Microfluidic-SANS: flow processing of complex fluids.
in Scientific reports
Rushworth C
(2012)
Cavity-enhanced optical methods for online microfluidic analysis
in Chemical Physics Letters
Watanabe T
(2014)
Microfluidic approach to the formation of internally porous polymer particles by solvent extraction.
in Langmuir : the ACS journal of surfaces and colloids
Description | This project enabled the coupling of microfluidic devices with a spectroscopy for the detection of very small liquid volumes at very low concentrations. Microfluidics - the controlled handling of liquids in small volumes (pL-microL) - is a powerful platform for the synthesis, discovery and analysis of chemical, biological and physical sciences. It is particularly impactful in flow chemistry. To fulfill its potential, researchers need to measure, non-invasively and rapidly, reaction processes. While normal spectroscopy suffers from low signal (due to small sample volume), our optical cavity approach overcomes this challenge by effectively extending the sample size by several orders of magnitude. The coupling of these two approaches required the refinement of both microfabrication and optical cavities, and eventually resulted in a robust ultra-sensitive detection system for droplet flow chemistry with potential for: flow chemistry, drug discovery, marine science and bio-analytical and environmental sciences. So far, only visible detection was demonstrated, mono and polychromatic - this can be further extended to IR and UV depending on need. |
Exploitation Route | This approach can (and, in part, has already) be employed for high-sensitivity detection of composition and reaction kinetics in: flow chemistry and drug-discovery, marine and environmental sciences, as well as a within microfluidics platforms in general. |
Sectors | Aerospace Defence and Marine Agriculture Food and Drink Chemicals Energy Environment Healthcare Manufacturing including Industrial Biotechology Pharmaceuticals and Medical Biotechnology Security and Diplomacy |
Description | In partnership with Pfizer and Oxford University, this flow chemistry award enabled the development of the first microfluidic approach compatible with optical spectroscopy. The challenge of small path lengths (due to small sample volumes) has been overcome by employing optical cavities that 'bounce' light beams multiple times within a single volume. Visible light, both mono- and polychromatic has been demonstrated to measure composition and gauge reaction kinetics (and mechanism) in both continuous and droplet flows. We have demonstrated the approach with several model reactions with a fingerprint in the visible range. In concert with Pfizer, we evaluated reactions of interest in flow chemistry. Scientific publications defined the potential and limitations of the approach, as well as possible extensions with fibre optics, multiple diode lasers and white sources, and miniaturization for portability. |
First Year Of Impact | 2011 |
Sector | Aerospace, Defence and Marine,Chemicals,Environment,Healthcare,Manufacturing, including Industrial Biotechology,Security and Diplomacy |
Impact Types | Economic |
Description | Procter and Gamble research contract |
Amount | £200,000 (GBP) |
Organisation | Procter & Gamble |
Sector | Private |
Country | United States |
Start | 07/2014 |
End | 08/2016 |
Title | Microfluidic FPP devices |
Description | Rapid prototyping method for microfluidic devices |
Type Of Material | Improvements to research infrastructure |
Year Produced | 2012 |
Provided To Others? | Yes |
Impact | Inexpensive, accurate and rapid microfabrication approach available to a wide range of researchers |
URL | http://www.imperial.ac.uk/polymers-and-microfluidics/research/micro-reaction-engineering/ |