Real-time sampling and identification of airborne chemicals using optical tweezers

将开发一种新的分析方法，用于实时采样、识别和量化大气颗粒物中发现的特定环境气溶胶成分，包括分析化学战剂存在的可能性。这种方法将用于调查和改进物理化学性质（例如，亨利定律常数、水解速率常数），这些性质决定了大气物种的大气寿命以及可能的化学武器区。来自人为污染源的环境有机化合物以蒸气/气相或分散的固体颗粒或液滴的形式存在于大气中。同样，如果释放化学武器，预计将分散在气相和颗粒相之间。因此，环境空气的采样和表征以使得能够检测危险化合物必须是快速的并且响应于气体/气溶胶颗粒组成的变化。潜在化学武器的鉴定必须是特异性的，成功地与背景环境物种区分开来，并导致对该物质的稳健、明确的鉴定。任何新技术都应是多功能的，以便能够在同一分析中识别广泛的危害以及背景化合物，并能够对气相物质和凝聚相颗粒（直径通常大于100纳米）进行取样和分析。单个气溶胶探针液滴可以允许对来自气流的气相和颗粒相物质进行响应性和快速采样（第二时间尺度），可以是需要很少样品的超小体积（小于pL），并且可以容易地配置有常规分析技术，例如拉曼光谱。在这里，我们将开发使用气溶胶光镊隔离一个单一的探针气溶胶液滴（或甚至是一个阵列的探针液滴）的时间不确定的一段时间，作为一个超灵敏的采样体积的环境颗粒或气体成分，检测，识别和监测存在于环境气溶胶中的物种。

A new analytical approach for real-time sampling, identifying and quantifying specific ambient aerosol components found in atmospheric particulate matter, including the potential to analyse the presence of chemical warfare agents (CWAs), will be developed. This approach will be used to investigate and refine the physicochemical properties (e.g. Henry's law constants, hydrolysis rate constants) that govern the atmospheric lifetimes of atmospheric species as well as possible CWAs. Ambient organic compounds from anthropogenic pollution sources are present in the atmosphere in both the vapour/gas phase or as dispersed solid particles or liquid droplets. Similarly, CWAs if released would be expected to be dispersed between the vapour and particle phase. Thus, sampling and characterisation of ambient air to enable detection of a hazardous compounds must be rapid and responsive to changes in gas/aerosol particle composition. The identification of potential CWAs must be specific, discriminating successfully from background ambient species, and leading to the robust, unambiguous identification of the agent. Any new technique should be multiplexed, allowing the identification of a broad range of hazards as well as background compounds in the same analysis, and able to sample and analyse both gas phase species and condensed phase particles (typically >100 nm in diameter). A single aerosol probe droplet can allow responsive and rapid sampling of gas phase and particle phase species from an airflow (second timescale), can be ultra-small in volume (less than pL) requiring little sample, and can be readily configured with conventional analytical techniques such as Raman spectroscopy. Here, we will develop the use of aerosol optical tweezers to isolate a single probe aerosol droplet (or even an array of probe droplets) for an indefinite period of time to act as an ultra-sensitive sampling volume of ambient particles or gas constituents to detect, identify and characterise species present in ambient aerosols.