雁过无痕
第1楼2008/06/12
看含量才能推测测试大致的时间,一般大约200/小时.因为是天然丰度要定量,所以可能比较费时间.
对于瓦里安的仪器,可能单脉冲谱上在112处会有本底(不知道新仪器解决了没),所以建议问有布鲁克仪器的单位.
定量时请注意给够脉冲延迟
aytdy
第5楼2008/06/16
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).
雁过无痕
第7楼2008/06/17
用交叉极化定量?不能这么干滴