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

化学系的环境化学科学项目将资助巴尔的摩县马里兰大学(UMBC)的Lee Blaney教授和巴尔的摩马里兰大学(UMB)的Katherine Squibb教授研究环境中有机金属物质的化学。这个项目试图了解由于直接和间接的太阳光解而造成的有机金属化合物的环境变化。有机砷、-铂、-硒和-锡化合物被包括在这项研究中，因为它们在环境系统中广泛存在。两名博士生和一些本科生助教参与了相关研究。该项目团队与密歇根大学迈耶霍夫学者计划(MSP)和妇女技术中心(CWIT)合作，从对环境化学感兴趣的代表性不足的群体中招募学生。此外，PIS与MSP、CWIT和UMBC本科教育办公室合作，邀请来自代表性不足群体的学生参加工作坊、研讨会和演示，目标是促进环境化学科学的本科生研究和教育。这项研究的某些方面正在被纳入环境化学(UMBC)和高级毒理学(UMB)的研究生水平课程。正在开发用于有机金属的固相萃取液相色谱-串联质谱仪(SPE-LC-MS/MS)的先进分析方法，以加强对转化产物的识别和定量。对于直接和间接光解机理，通过pH和波长梯度测定了8种有机金属物质的摩尔消光系数和光转化动力学。此外，正在确定这些化学物质从有机形式到贱金属物种的转化途径。由于有机金属及其贱金属的毒性不同，采用了一种有针对性的生物测定方法来证明光解降解过程中毒性的变化。更具体地说，研究目标包括：(I)建立这些有机金属物种的固相萃取液相色谱电喷雾电离串联质谱仪(SPE-LC-ESI-MS/MS)分析方法；(Ii)测量城市地表水中直接和间接光解所关注的有机金属化合物的转化动力学；(Iii)识别目标有机金属化合物直接和间接光解形成的转化产物；以及(Iv)利用有针对性的生物测定方法表征含有有机金属化合物的溶液和光转化产物的剩余生化活性。这一研究方法有望提高对有机金属化合物在环境系统中的光化学命运的理解。

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.