Collaborative Research: Photolysis of environmentally-relevant organometallic compounds in aqueous matrices

有了这个奖项，化学系的环境化学科学项目资助马里兰大学巴尔的摩分校（UMBC）的Lee Blaney教授和马里兰大学巴尔的摩分校（UMB）的Katherine Squibb教授研究环境中有机金属物质的化学性质。该项目旨在了解有机金属化合物由于直接和间接的太阳光解作用而产生的环境变化。有机砷、-铂、-硒和-锡化合物被包括在本研究中，因为它们在环境系统中广泛存在。两名博士研究生和一些本科生助理参与了相关研究。项目团队与UMBC迈耶霍夫学者计划（MSP）和技术女性中心（CWIT）合作，从代表性不足的群体中招募对环境化学感兴趣的学生。此外，PIs与MSP、CWIT和UMBC本科教育办公室合作，让来自代表性不足群体的学生参加讲习班、研讨会和示范，目的是促进环境化学科学的本科研究和教育。研究的选择方面被纳入研究生水平的课程环境化学（UMBC）和高级毒理学（UMB）。利用固相萃取-液相色谱-串联质谱法（SPE-LC-MS/MS）对有机金属进行分析，以提高转化产物的鉴定和定量。在不同的pH和波长梯度下测定了8种有机金属物质的摩尔消光系数和光转化动力学，并对其直接和间接光解机理进行了研究。此外，这些化学物质从有机形态到贱金属形态的转化途径正在被确定。由于有机金属及其贱金属的毒性不同，因此采用靶向生物测定方法来证明光解降解毒性的变化。具体而言，研究目标包括：(i)开发固相萃取-液相色谱-电喷雾电离串联质谱（SPE-LC-ESI-MS/MS）分析方法；在城市地表水中通过直接和间接光解测量所关注的有机金属化合物的转化动力学；（iii）识别通过目标有机金属化合物的直接和间接光解形成的转化产物；（iv）使用目标生物测定方法表征含有有机金属化合物和光转化产物的溶液的剩余生化活性。这种研究方法有望提高对环境系统中有机金属化学品光化学命运的理解。

With this award, the Environmental Chemical Sciences Program in the Division of Chemistry is funding Professor Lee Blaney of the University of Maryland, Baltimore County (UMBC) and Professor Katherine Squibb of the University of Maryland, Baltimore (UMB) to investigate the chemistry of organometallic substances in the environment. This project seeks to understand the environmental transformations of organometallic compounds due to direct and indirect solar photolysis. Organoarsenic, -platinum, -selenium, and -tin compounds are included in this research because they are widespread in environmental systems. Two PhD-level graduate students and a number of undergraduate assistants are involved with the associated research. The project team works with the UMBC Meyerhoff Scholars Program (MSP) and Center for Women in Technology (CWIT) to recruit students from underrepresented groups who are interested in environmental chemistry. In addition, the PIs partner with MSP, CWIT, and the UMBC Office of Undergraduate Education to engage students from underrepresented groups in workshops, seminars, and demonstrations, with a goal to promote undergraduate research and education in the environmental chemical sciences. Select aspects of the research are being incorporated into graduate level courses in Environmental Chemistry (UMBC) and Advanced Toxicology (UMB).Advanced analytical methods are being developed using solid-phase extraction liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) for organometallics to enhance identification and quantitation of transformation products. The molar extinction coefficients and photo-transformation kinetics of eight organometallic substances are being determined across pH and wavelength gradients for direct and indirect photolysis mechanisms. Furthermore, the transformation pathways for these chemicals from the organic form to the base metal species are being identified. As the toxicity of organometallics and their base metals differ, a targeted bioassay approach is employed to demonstrate changes in toxicity with photolytic degradation. More specifically, the research aims include: (i)developing solid-phase extraction liquid chromatography electrospray ionization tandem mass spectrometry (SPE-LC-ESI-MS/MS) analytical methods for these organometallic species; (ii) measuring the transformation kinetics of the organometallic compounds of concern by direct and indirect photolysis in urban surface water; (iii)identifying transformation products formed through direct and indirect photolysis of targeted organometallic compounds and (iv) characterizing the residual biochemical activity of solutions containing organometallic compounds and phototransformation products using a targeted bioassay approach. This research approach is expected to improve understanding of the photochemical fate of organometallic chemicals in environmental systems.