Droplet microfluidic based chemical sensors for rapid measurement of nutrients in water

Traditionally most chemical parameters (e.g. nitrate, phosphate) in aquatic environment are measured by laboratory analysis of discrete water samples. Microfluidic sensors offer an attractive alternative: by taking and analysing samples autonomously in situ, they obviate sampling allowing larger datasets particularly when used in conjunction with autonomous systems.
The current state-of-the-art sensors have temporal resolution of minutes due to Taylor dispersion (fluid flow effectively smears chemical composition within the device) and complex valve controls, making them high-cost and unsuitable for deployments requiring high frequency measurement - most notably on profiling vehicles (e.g. Argo floats, oceanic gliders) that rapidly transect the water column.
Droplet microfluidics (in which nano litre water samples are taken and subsequently operated on as droplets within an immiscible oil) is a novel microfluidic method that, in addition to other advantages, crucially offers zero Taylor dispersion and much higher analytical throughput.
This project will develop the first-ever droplet-flow based field-deployable sensor for autonomous systems. Low-cost, low-powered and fully functional; the device will be a step-change in high-frequency autonomous aquatic chemical analysis.

This project will benefit society through enabling new capabilities and services to reduce cost and improve the quantity and quality of data from the aquatic environment monitoring. This in turn will lead to 1) earlier detection of pollution and improved management of water resources, 2) improved prediction of climate change and environment monitoring through regulatory testing and compliance management. These impact will be achieved through industrial and regulatory user groups via deploying autonomous (i.e. left on site or location unattended) or hand held instruments that will produce better, cheaper data at higher spatial and temporal density.
This project will contribute to UK's economy and industry for environmental sensing and monitoring technologies, by providing competitive technologies on sensor systems. This will in particular benefit SMEs that we have already collaborated with.
The project will deliver new knowledge and scientific advances in micro systems engineering. With the future application of the sensor system, we expect to collect unprecedented environmental data. These results will be disseminated via publication, seminar, conference and uptake by the respected agencies to a much wider end-user community.
Last but not least, young scientists (postdoc and PhD student) and engineers will be trained in this project and following programs to enhance the leading position of UK in water analysis.