主题：【分享】谁能用固态核磁分析腐殖酸结构组成？收费多少？

原文由 hail_zhang 发表:
用交叉极化定量？不能这么干滴

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).

原文由 nmrbj 发表:
腐殖酸确实是用交叉极化方法测试的。因为单脉冲可能无法得到足够的信号强度来积分。文献中都是这样做的。
但是需要注意的是：有些取自天然的腐殖酸含有很多铁磁性金属杂质，会干扰测试。最好用酸处理除掉。
具体情况还要具体分析，如转速，弛豫时间等要根据样品情况决定。