Guenneau F, Mutzenhardt P, Grandclaude D, Canet D
Laboratoire de Méthodologie RMN, (UPRESA CNRS 7042; FR CNRS 1742-INCM), Université Henri Poincaré, Vandoeuvre-les-Nancy Cedex, 54506, France.
J Magn Reson. 1999 Sep;140(1):250-8. doi: 10.1006/jmre.1999.1829.
It is shown that fully J-decoupled homonuclear spectra involving Lorentzian lines can be readily obtained by straightforward processing of the 2D data arising from a conventional spin echo sequence (pi/2-t(1)/2-pi-t(1)/2-Acq(t(2))) used in the so-called J-resolved experiment. The method simply rests on power spectra with the drawback of lines having meaningless relative intensities. In principle, the experiment should also yield transverse relaxation times. Several tests demonstrate that this is not so, due to pulse imperfections and nonresolved long-range J couplings. Conversely, longitudinal and rotating frame relaxation times can be easily determined by means of an appropriate preparation period (for instance, a saturation-recovery period in the case of longitudinal relaxation) inserted before the 2D spin echo sequence. Since one is dealing with a single line per nucleus, relaxation measurements become reliable and accurate.
结果表明，通过对所谓J分辨实验中使用的常规自旋回波序列（π/2 - t(1)/2 - π - t(1)/2 - Acq(t(2))）产生的二维数据进行直接处理，能够轻松获得包含洛伦兹线的完全J解耦同核谱。该方法基于功率谱，缺点是谱线的相对强度无意义。原则上，该实验也应能得出横向弛豫时间。多项测试表明，由于脉冲缺陷和未分辨的长程J耦合，情况并非如此。相反，通过在二维自旋回波序列之前插入适当的准备期（例如，纵向弛豫情况下的饱和恢复期），可以轻松确定纵向和旋转坐标系中的弛豫时间。由于每个原子核对应一条谱线，弛豫测量变得可靠且准确。
