RUI: New Devices and Methods for Microscale Spectroelectrochemistry

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In this project funded by the Chemical Measurement & Imaging Program of the Chemistry Division, Professor Paul Flowers of the Department of Chemistry & Physics at the University of North Carolina at Pembroke is developing new devices and protocols for the chemical analysis of very small samples. This research creates new tools and methodology for microscale chemical analysis that offer advantages in analysis time, cost and sample size requirement relative to comparable existing techniques. The project employs undergraduate assistants selected from a diverse population that is 16% American Indian and 33% African American, engaging significant numbers of students in ethnic and racial groups that are presently underrepresented in the nation's scientific workforce. Curricular laboratory activities directly related to the research are being developed and integrated into existing chemistry courses at the sophomore and senior levels, significantly broadening the educational impact of the project.Spectroelectrochemistry (SEC) refers to the simultaneous application of spectroscopic and electrochemical techniques and typically involves making spectral measurements on samples undergoing electrolysis. Since the first reports of SEC in the 1960s, these techniques have become well-established tools for characterizing the redox properties of chemical species and elucidating the mechanisms of electrode processes. A more recent and growing effort is directed towards the use of SEC as the basis for quantitative chemical analyses, essentially replacing the chemical reagents used in conventional assays with an inert, nonexpendable electrode. Professor Flowers'group has previously developed a prototype device that permits SEC analysis of sample volumes well below one microliter, roughly two-orders of magnitude lesser than any other reported device. In this project, the basic design of this prototype is being adapted to permit flow analyses of microliter and sub-microliter samples. Simple polymer casting techniques are being utilized to fabricate these flow cells, and their performance is being evaluated using voltammetry, coulometry, chronoabsorptometry and voltabsorptometry. In parallel to the device fabrication work, microscale assays that exploit SEC measurement strategies are being developed for selected compounds of biological and biomedical relevance.