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小鸟蘑菇木虫 (小有名气)
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[求助]
PEG钝化制备上转化的GQDs
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按照文献用PEG钝化GQDs表面，制备具有上转化发光性质的GQDs，方法附后。 有谁做过的，能不能帮忙看下，下面几个问题： 1. 用Na2CO3调节pH为8时，Na2CO3的浓度和加入量有没有影响？要用多少呢？ 2. 还原用的水合肼量和浓度怎么控制呢？ 3. 用0.22um滤膜过滤那步，直接离心分离、取上清液，也可以吧？ 4. 最后一步的透析，完成后得到的应该还是GQDs的溶液吧，那怎么确定浓度呢？ 不胜感激！ The preparation of GQDs with an oligomeric PEG1500N as the surface passivation agent. GO were prepared from natural graphite powder by a modified Hummers method. The sample GO（0.05 g）was treated in an aqueous nitric acid solution (up to 2.6 M) （40 mL）with 70 oC reflux for 24 h. After cooling to room temperature, the suspension was under mild ultrasonication. The pH was tuned to 8 with Na2CO3. The suspension was filtered through a 0.22 μm microporous membrane to remove the large tracts of GO. In a typical reaction, PEG1500N (2g) was mixed with the cutting GO solution, and the mixture was substantially mixed. The mixture solution was heated at 120 oC for 24 h. And then, graphene oxide is reduced by hydrazine hydrate at 100 oC for 24 h. After cooling to room temperature, the resulting solution was filtered and a yellow solution was separated. So, the mixture solution was further dialyzed in a dialysis bag (retained molecular weight: 14,000 Da) for 7~10 days and GQDs were then strongly fluorescent. |
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小鸟蘑菇
木虫 (小有名气)
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2楼2013-05-28 14:10:55
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