User:Raithathar/Notebook/DBR Lab Notebook/2019/11/05

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11/5 (Day 13) Since our last Au Seed crashed and did not produce any gold precipitate after being redispersed in CPC, our goal for today's lab was to synthesize a better Au Seed. We corrected our problems from last time by being consistent with the centrifugation times and synthesizing new solutions (NaBH4, Ascorbic Acid, CPC, CTAB, AgNO3, HAuCl4). The smaller Au Seed that is formed by the sequential addition of 125 μL of 10 mM HAuCl4 and 300 μL of 10 mM of ice-cold NaBH4 to 5 mL of 100 mM CTAB. This mixture was stirred for five minutes. The correct color of light orange was seen after this period of stirring, so we moved onto the synthesis of the larger Au Seed. Following the same protocol as in previous runs, we obtained two solutions with a dark purple color and placed them into incubation in 40C overnight. However, when we removed the samples from incubation, they were once again clear and contained little to no gold precipitate. We will try to synthesize a batch of Au Seed tomorrow with new NaBH4 and CTAB.