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

将开发一种新的分析方法，用于对大气颗粒物中发现的特定环境气溶胶成分进行实时采样、识别和量化，包括分析化学战剂的存在的可能性。这一方法将被用来研究和改进控制大气物种以及可能的化学气体的大气寿命的物理化学性质(例如亨利定律常数、水解速率常数)。来自人为污染源的环境有机化合物以气/气相或分散的固体颗粒或液滴的形式存在于大气中。同样，CWAs如果释放，预计将分散在汽相和颗粒相之间。因此，为了能够检测到有害化合物，对环境空气的采样和表征必须是快速的，并对气体/气溶胶颗粒成分的变化作出反应。潜在CWA的鉴定必须是特定的，成功地与背景环境物种区分开来，并导致强健、明确的病原体鉴定。任何新技术都应该是多重的，允许在同一分析中识别广泛的危害和背景化合物，并能够采样和分析气相物种和凝聚相颗粒(通常直径为100 nm)。单个气溶胶探头液滴可以对气流中的气相和颗粒相物种进行响应和快速采样(秒时间刻度)，体积可以非常小(小于Pl)，需要很少的样品，并且可以很容易地与传统的分析技术(如拉曼光谱)一起配置。在这里，我们将开发使用气溶胶光学镊子来无限期地分离单个探测气溶胶微滴(甚至是一系列探测微滴)，作为环境颗粒物或气体成分的超灵敏采样体积，以检测、识别和表征环境气溶胶中存在的物种。

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.