Characterization of the pH of Organic/Inorganic Aerosol Using Ratiometric Fluorescence Imaging

使用比例荧光成像表征有机/无机气溶胶的 pH 值

• 批准号: 2203634
• 负责人: Miriam Freedman
• 金额: $ 48.84万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203634&HistoricalAwards=false
• 关键词: Characterization; pH; Organic; Inorganic; Aerosol

The Environmental Chemical Sciences Program in the Division of Chemistry funds Professor Miriam Freedman for this project which is focused on the acidity of aerosols. This property of aerosol particles impacts chemical reactions in the atmosphere as well as human health. Based on the composition of aerosol particles and gas-phase molecules, the acidity of aerosol particles can be estimated using models. These models predict that aerosol particles are highly acidic, but results differ depending on the model used. This project aims to develop a novel direct measure of aerosol acidity using carbon quantum dots. Using this approach will make it possible to explore the molecular origins of the high acidity of aerosol particles for both marine and continental environments. Further development of the probes will enable applications in atmospheric chemistry studies or in other fields where highly acidic samples are of interest. This project has potential for technology transfer, provides training for undergraduate and graduate students, and supports dissemination to the public through outreach events.To study the acidity of aerosol particles, this project will use ratiometric fluorescence imaging of carbon quantum dots. Currently, the Freedman research group has developed a probe that covers the pH range of 0 – 3.5. To determine the origins of the high acidity of continental and marine aerosol, the pH of model systems of organic compounds with salts will be characterized. Ammonium sulfate will be used for model continental aerosol and sodium chloride will be used for model marine aerosol. The organic compounds are chosen to be relevant for the specific type of aerosol as well as to have a range of pKa values, a range of complexities in composition from single organic compounds to mixtures, and a range of surface activities. To develop the probe further, the project aims to increase the pH range that can be measured, incorporate an internal standard, and deposit the probe on substrates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

化学系的环境化学科学计划为米里亚姆·弗里德曼教授提供资金，用于该项目，该项目的重点是气溶胶的酸度。气溶胶颗粒的这种特性会影响大气中的化学反应以及人类健康。根据气溶胶颗粒和气相分子的组成，可以使用模型来估计气溶胶颗粒的酸度。这些模型预测气溶胶颗粒是高度酸性的，但结果因所用模型的不同而不同。该项目旨在开发一种利用碳量子点直接测量气溶胶酸度的新方法。使用这种方法将有可能探索海洋和大陆环境中气溶胶粒子高酸度的分子根源。探测器的进一步发展将使其能够应用于大气化学研究或其他对高酸性样品感兴趣的领域。该项目具有技术转移的潜力，为本科生和研究生提供培训，并支持通过外展活动向公众传播。为了研究气溶胶粒子的酸度，该项目将使用碳量子点的比率荧光成像。目前，弗里德曼研究小组已经开发出一种可以覆盖PH值范围为0-3.5的探测器。为了确定陆地和海洋气溶胶高酸度的来源，将对有机化合物与盐的模型体系的pH值进行表征。硫铵将用于模拟大陆气溶胶，氯化钠将用于模拟海洋气溶胶。有机化合物被选择为与特定类型的气溶胶相关，并具有一定的pKa值，从单一有机化合物到混合物的组成的一系列复杂性，以及一系列的表面活性。为了进一步发展探头，该项目旨在增加可测量的pH值范围，纳入内部标准，并将探头放置在基质上。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。