24小时热门版块排行榜

>论坛更新日志 (3701)
>文献求助 (346)
>虫友互识 (288)
>导师招生 (274)
>博后之家 (139)
>硕博家园 (138)
>休闲灌水 (136)
>论文投稿 (109)
>考博 (108)
>基金申请 (81)
>教师之家 (48)
>招聘信息布告栏 (47)
>考研 (40)
>公派出国 (39)
>绿色求助(高悬赏) (32)
>找工作 (29)

返回列表

iwindfeng

铁虫 (初入文坛)

应助: 0 (幼儿园)
金币: 1
帖子: 19
在线: 29.6小时
虫号: 3313566
注册: 2014-07-08
性别: GG
专业: 无机纳米化学

[求助] 较稀纳米材料分散液的浓度表征已有1人参与

超声法分散（剥离）固体制备分散液的方法想必各位大虾都不陌生了吧，现在小弟对文献中分散液的浓度是怎么测定出来的有一些不解，希望各位大佬赐教。
典型的情况是，分散液的制备会经历超声与离心两步，最终的浓度文献上通常给出的是mg/mL的量级。如果是比较浓的（20mg/mL之类)倒是可以直接称，但是样品是那种分散得不太好的（0.1mg/mL往下）得怎么办呢？
刚刚小弟扒文献（J. Mater. Chem., 2012,22, 21507-21512 ）看到一个微克每毫升浓度的，大概步骤如下：
Graphite flakes (50 mg) were sonicated for 60 min. in the appropriate solvent (100 mL, NMP or o-DCB; see Table S1). After that period, the material was centrifuged for 15 min. at 2500 rpm and the black supernatant was collected. An aliquot (5 mL) was used for recording the absorbance at 660 nm. The remaining supernatant was filtered through a pre-weighted Nylon membrane filter (pore size 0.2 µm), which was then placed in a vacuum oven and dried at 60 °C for 16 hours. After that period, it was carefully weighted and the concentration of exfoliated graphene in the appropriate solvent (i.e. NMP or o-DCB) was calculated (see Table S1).
就是说将分散液用滤膜过滤，称重得到质量差。然而……就最浓的分散液来说，这个质量差才0.38mg,手残的我想象不到怎么个carefully法才能将误差控制到这个程度……

另外这办法对量子点也没用吧，很好奇这种数据要怎么样才能做出来，谢谢各位。

回复此楼