User:Maria Briscione/Notebook/Chem 571/2011/09/07

Biomaterials Design Lab

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Objective The purpose of this subset of experiments was to monitor the change in concentration of AuNPs at various pHs (7.55 and 7). Description solutions of chloroauric acid (0.25mM) and BSA (1.5µM) in 10mL of water or buffer were added together (1mL of chloroauric acid (stock 2.5 mM), 1mL of BSA (Stock 15 µM), 8mL of water or buffer-Tris pH 7.55). A UV-vis spectrum was analyzed at 0 seconds (t0) and after thirty minutes following. The samples were placed in an 80 degree Celsius oven while the reaction proceeded. A spectrum of a blank solution of pH buffer was also analyzed. The zein film from the previous experiment was observed under a microscope Data Sample 1 (water) contained 8.10mL of water and 1 mL of BSA and 1mL of chloroauric acid Sample 2 (buffer) contained 8.15mL of Tris 7.55 buffer and 1mL of BSA and 1mL of chloroauric acid WATER BUFFER Notes The increase in concentration at 550 nm observed after 60 minutes appears rather peculiar. An increase in concentration would be expected to continue or at least plateau for the duration for the duration of the experiment. In this case, the concentration returns to baseline readings. I conclude that this increase is instead an error introduced into our 60 minute trial.