Development of Methods for Quantifying Speciated Peroxy Radicals by Chemical Ionization Mass Spectrometry

该项目的目标是开发新的方法来量化大气中的活性物质，并提高在其测量中使用的校准方法的准确性和可靠性。重点放在过氧基的测量上，过氧基是参与有机化合物光化学转化的活性物种，可导致臭氧和二次气溶胶等二次产物的形成。这项研究的结果将提高评估依赖于基础自由基化学的大气化学模型的能力。两种新的过氧基形成方法包括使用氨离子或烷基胺离子的大气压横向电离技术，以及一种间接方法，即过氧基被化学转化为氢过氧化物，然后使用碘化物或溴化物化学电离质量(CIMS)光谱进行检测。这些新技术将在纽约市和新泽西州林区的现场部署期间进行测试，涉及氮氧化物(NOx)浓度和挥发性有机化合物(VOC)前体的广泛范围。这项工作还包括开发一种基于甲醛光解的新校准源。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。

The goals of this project are to develop new methods for quantifying reactive species in the atmosphere and to improve the accuracy and reliability of the calibration methods used in their measurement. The focus is on the measurement of peroxy radicals, reactive species that participate in photochemical transformations of organic compounds that can lead to the formation of the secondary products, such as ozone and secondary aerosol. The results of this study will lead to an improved ability to evaluate atmospheric chemistry models that rely on a solid understanding of underlying radical chemistry.Two new methods for speciating peroxy radicals include an atmospheric pressure transverse ionization technique using ammonium or alkyl amine ions, and an indirect method in which peroxy radicals are chemically converted to hydroperoxides and then subsequently detected using iodide or bromide chemical ionization mass (CIMs) spectrometry. These new techniques will be tested during field deployments in New York City and in a forested area in New Jersey, spanning a wide range in nitrogen oxide (NOx) concentrations and volatile organic compound (VOC) precursors. This effort also includes the development of a new calibration source based on formaldehyde photolysis.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.