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

传统上，水环境中的大多数化学参数（如硝酸盐、磷酸盐）是通过对离散水样的实验室分析来测量的。微流体传感器提供了一种有吸引力的替代方案：通过在现场自主采集和分析样本，他们可以在更大的数据集上进行采样，特别是当与自主系统结合使用时。由于泰勒色散，目前最先进的传感器的时间分辨率为分钟（流体流动有效地涂抹装置内的化学成分）和复杂的阀控制，这使得它们成本高，不适合需要高频率测量的部署-特别是在快速横切水柱的剖面探测器（如Argo浮标、海洋滑翔机）上。液滴微流体（其中纳升水样品被采集，随后作为不混溶油中的液滴进行操作）是一种新型的微流体方法，除了其他优点之外，该方法还提供了零泰勒分散和更高的分析通量。该项目将为自主系统开发第一个基于液滴流的现场可部署传感器。低成本、低功耗和功能齐全;该设备将是高频自主水化学分析的一个飞跃。

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.