原文由 aytdy 发表:
一个吸附实验,固态核磁测定腐殖酸结构,目的是看一下其中的芳香烃所占百分比和脂肪烃所占百分比。 我见文献用的是固态魔角旋转核磁,它利用测定所得谱图,对不同位移的峰进行积分后即可计算出结构组成比例。它把0-50 ppm积分后计算所占比例,即为脂肪烃所占百分比;把112-145 ppm积分计算所占比例,即为芳香烃所占百分比。
不知哪里能测定?两个腐殖酸样品大约需要多少钱?谢谢!
本人联系方式:astdy@126.com
原文由 aytdy 发表:
我用化学法测过碳含量在55%左右,文献测定数据如下,请帮忙估计一下测定所需时间,我好向老师汇报费用问题。不胜感谢!!!
Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance experiments were performed on a Bruker AMX400 operating at 100.625 MHz on carbon-13. The rotor spin rate was set at 4500 Hz. A recycle time of 1 s and an acquisition time of 13 ms were used.
All the experiments were conducted with the variable contact time (VCT) pulse sequence in order to find the optimal contact time (OCT) for each sample and to minimize the error on the evaluation of the peak areas (Conte et al., 1997). OCT of 1 ms was measured for HA~, FA 1 and FA 2, and of 0.8 ms for HA~. A line broadening of 50 Hz was used to transform all the FIDs.
Structural carbons determined were aliphatic carbon (0-50 ppm), alcohols, amines, carbohydrates, ethers,methoxyl and acetal carbon (50-112 ppm),aromatic carbon (112-145 ppm), phenolic carbon (145-163ppm), and carboxyl and carbonyl carbon (163-215 ppm).