Stamps J P, Ottink B, Visser J M, van Duynhoven J P, Hulst R
Department of Chemical Analysis, University of Twente, 7500 AE Enschede, The Netherlands.
J Magn Reson. 2001 Jul;151(1):28-31. doi: 10.1006/jmre.2001.2352.
Diffusion-ordered spectroscopy (DOSY) has gained considerable attention over the past decade as a useful tool for calculating diffusion-related parameters or in the analysis of complex (reaction) mixtures. A major drawback of the established methods are the relatively long recording times needed to acquire the spectra, excluding the monitoring of rapidly progressing reactions and (hence) measurements of less stable components. In order to overcome these shortcomings a new pulse sequence, Difftrain, has been developed. The sequence involves stimulated echo attenuation, multilow flip angle excitation, and multiple sampling of the FID during the longitudinal storage. The calculated diffusion parameters obtained by Difftrain were compared with those obtained by the established sequence BPPSTE (bipolar pulse pair stimulated echo) and were in good agreement. For systems with moderate to good signal-to-noise ratios the Difftrain building block yields significant saving in recording time (single-shot acquisition instead of acquiring n-different gradients strengths), thus opening up new applications in nonequilibrium systems and screening of compositions and/or interactions of (larger) compound arrays.
在过去十年中，扩散排序光谱法（DOSY）作为一种用于计算扩散相关参数或分析复杂（反应）混合物的有用工具，已受到广泛关注。现有方法的一个主要缺点是获取光谱所需的记录时间相对较长，这排除了对快速进行的反应的监测以及（因此）对不太稳定成分的测量。为了克服这些缺点，开发了一种新的脉冲序列Difftrain。该序列涉及受激回波衰减、多低翻转角激发以及在纵向存储期间对自由感应衰减（FID）的多次采样。将通过Difftrain获得的计算扩散参数与通过既定序列BPPSTE（双极脉冲对受激回波）获得的参数进行比较，结果吻合良好。对于具有中等至良好信噪比的系统，Difftrain模块可显著节省记录时间（单次采集而非采集n个不同梯度强度），从而在非平衡系统以及（较大）化合物阵列的组成和/或相互作用筛选方面开辟了新的应用。
