Summary

My time was well spent this summer in lab. I gained greater confidence and knowledge of procedures and protocol in lab, but I also learned a great deal about the underlying chemistry behind my project and topic in general. The main objective of my project was to learn more about the underlying kinetics of Rhodamine 560 (R560) compared to Rhodamine B (RB), which was previously studied on the 532nm laser. R560 studies were done by a previous student, but on a 470nm laser, so my job was to obtain data for R560 back on the 532nm laser to compare the Rhodamine derivative to RB, and see whether differences between R560 and RB were due to laser wavelength or because of difference in structure and underlying kinetic behaviors. Data for R560 specifically entails blinking traces of single molecule scans, which graph intensity vs. time, in order to track fluorescence and electron transfer kinetics.

Knowing that R560 could be difficult to obtain data on the 532nm, which is far from its optimal excitation wavelength, the parsed times alternative was also explored. By parsing the blinking traces into early and late, I could see whether the early and late showed statistical difference/similarities in fits. Assuming that RB undergoes dealkylation into R560, its early and late times were predicted to be different while for R560, predicted to be different. Upon actually performing the analysis and fits, I found that the results did not match with our prediction. Possible issues regarding the randomness of the occurrence of blinking/fluorescence and RB actually undergoing degradation were recognized as possible influences to my obtained results.

Despite analyzing R560 using a non-optimal excitation wavelength, I was still able ot obtain scans of single molecules to my surprise. After collecting enough data on the molecule I was able to finally put the traces through Clauset analysis, and seeing how well it fit statistically to mathematical distributions. Comparing the final fits of R560 on 532nm laser, to those on the 470nm, I found that there was a difference in the fits. And when comparing it to the RB data, there was also a statistically significant difference as well. Now knowing that R560 and RB still demonstrate statistical differences in fits, the last concern resides in my R560 data on the 532nm laser. Recently, I have had troubles obtaining scans of the molecule, raising concerns whether I have been seeing an odd subset of R560 population that is simply behaving a certain way. After figuring out this concern, the data will demonstrate that R560 shows differences in electron transfer kinetics compared to RB, even using the same 532nm laser wavelength.

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