With support from the Chemical Measurement and Imaging Program, and co-funding from the Experimental Program to Stimulate Competitive Research, Profs. Rudolf Seitz and Roy Planalp from the University of New Hampshire, in collaboration with Prof. Shawn Burdette from the University of Connecticut, are developing and characterizing a new approach to preparing co-polymer based ratiometric fluorimetric indicators for metal ions. The approach separates complexation from fluorescence, thereby allowing preparation of ratiometric indicators for important metal ions like Cu(II), Pb(II), Fe(III), etc., which normally quench fluorescence.
This project will provide a new approach to measuring levels of toxic metals in municipal waters and will have a rapid and positive impact on public safety because of an established relationship with Envirosystems, Inc., a Womens Business Enterprise-certified company that can rapidly develop laboratory research for practical applications. The project will involve participants and trainees at many levels including high school, undergraduate, graduate, and postdoctoral, and will involve underrepresented groups and women. New students beginning on this project will be assigned a senior graduate student or postdoctoral mentor, who will share mentoring duties with the PI.
This project has endeavored to address the analysis and quantitation of a specific metal ion, copper, as processed and emitted from aqueous waste streams in populated areas. Among the analytical chemical challenges of the Earth's Environment and of the organisms that dwell therein, the focus has been on measuring copper in the toxic forms (whereby not all forms are toxic), and in the small concentrations of these forms. In doing so chemical identifying substances were developed that appropriately recognize this toxic form and that undergo a particular chemical change that can be easily interpreted with a light beam such as a laser. That recognizing process and interpretation are shown in the Figure. This indicator had the clear advantages of not having a quenched fluorescent response to copper(II) under appropriate circumstances, and also was easily modifiable and mountable on different supporting structures such as silica. The execution of this project involved the application of advanced inorganic and analytical chemical concepts and methodologies, in the design, synthesis and testing of the indicator. Particularly, the innate binding properties of copper(II) were compared to nickel(II) and zinc(II), two other metals that could give interfering results in the indicator response. The project yielded useful information that would allow this indicator to be tailored to particular concentrations of the copper, as well as information on detection of other toxic metals. When analyzing wastewater/sewage-treated samples, the indicator maintained chemical integrity as seen from its reliable light emission response to copper(II).
