Pesticide Transformation by Nitrogen Oxides on Leaf Surfaces

在这个由化学学部环境化学科学项目资助的项目中，布法罗大学的Ning Dai教授和Luis Velarde教授正在研究大气中氮氧化物对停留在叶子表面的农药变化的影响。由于农药在农业和城市环境中的广泛使用及其固有的毒性，发展准确预测这些分子暴露于环境时发生的变化的能力至关重要。该研究项目解决了目前在预测模型中未考虑的农药转化途径。该研究与协同教育活动相结合，包括研究生培训，本科生研究经验，将研究纳入布法罗大学环境工程课程，以及为高中教师和大布法罗地区代表性不足的高中学生提供公共科学推广。该项目确定了易受水和有机溶剂中氮氧化物反应影响的农药官能团。然后在模拟和真实的叶片表面上确定氮氧化物诱导农药转化的动力学和产物。考察了光照、农药配方、叶表皮蜡质结构等环境因素对反应的影响。最后，利用振动和频率产生（VSFG）光谱技术表征了农药及其转化产物在模型叶片表面的分子取向和系结。该表征技术用于将农药-叶片物理相互作用与氮氧化物-农药反应联系起来。

In this project funded by the Environmental Chemical Sciences Program of the Division of Chemistry, Professors Ning Dai and Luis Velarde at the University at Buffalo are investigating the contribution of atmospheric nitrogen oxides to the changes in pesticides which reside on leaf surfaces. Due to the widespread use of pesticides in agricultural and urban environments and their inherent toxicity, it is critical to develop capabilities to accurately predict the changes that occur in these molecules on exposure to the environment. This research project addresses a pesticide transformation pathway that is currently not considered in the predictive models. The research is integrated with synergistic educational activities, including training of graduate students, research experiences for undergraduate students, incorporation of research into the Environmental Engineering curriculum at the University at Buffalo, and public science outreach for high school teachers and underrepresented high school students in the Greater Buffalo region.This project identifies pesticide functional groups that are susceptible to nitrogen oxide reactions in water and organic solvents. The kinetics and products of nitrogen oxide-induced pesticide transformation are then determined on simulated and authentic leaf surfaces. The effects of environmental factors, including sunlight, pesticide formula, and the structure of leaf cuticle wax, on the reactions are also characterized. Lastly, vibrational sum frequency generation (VSFG) spectroscopy is employed to characterize the molecular orientation and tethering of surface-bound pesticides and their transformation products on model leaf surfaces. This characterizational technique is used to correlate the pesticide-leaf physical interaction with nitrogen oxide-pesticide reactions.