Henderson Terry J
U.S. Army Edgewood Chemical Biological Forensic Analytical Center, AMSRD-ECB-RT-AF, E5100, 5183 Black Hawk Road, Aberdeen Proving Ground, Maryland 21010-5424, USA.
J Am Chem Soc. 2004 Mar 31;126(12):3682-3. doi: 10.1021/ja039261+.
A scheme has been developed to eliminate virtually all signal intensity dependence on 1JCH in polarization transfers between 1H and 13C nuclei, reducing differences in signal intensity to only 1.5% over the entire natural 1JCH range. The scheme relies on the summation of time-domain data acquired with four suitably selected Delta delays so that the J dependence is essentially canceled in the final, signal-averaged free-induction decay. These Delta delays have been incorporated into the DEPT pulse sequence to create sensitivity-enhanced experiments for collecting quantitative 13C{1H} spectra. Four experiments, each with unique read pulse angles, give quantitative spectra with 200-300% more sensitivity than conventional 13C spectra acquired with inverse-gated 1H decoupling. The experiments are ideal for recording spectra with improved quantitative information or for substantially reducing the long acquisition times indicative of quantitative 13C experiments. The ability of the experiments to provide quantitative spectra was demonstrated with a simple ethylbenzene solution, however, they can easily be adapted to various applications for analysis of complex mixtures.
已经开发出一种方案，几乎可以消除1H和13C核之间极化转移中信号强度对1JCH的所有依赖性，在整个自然1JCH范围内将信号强度差异降低到仅1.5%。该方案依赖于对用四个适当选择的增量延迟采集的时域数据进行求和，以便在最终的信号平均自由感应衰减中基本消除J依赖性。这些增量延迟已被纳入DEPT脉冲序列，以创建灵敏度增强的实验来收集定量13C{1H}光谱。四个实验，每个实验都有独特的读取脉冲角度，其定量光谱的灵敏度比用反门控1H去耦采集的传统13C光谱高200 - 300%。这些实验非常适合记录具有改进定量信息的光谱，或者大幅减少定量13C实验中典型的长采集时间。通过一种简单的乙苯溶液证明了这些实验提供定量光谱的能力，然而，它们可以很容易地适用于分析复杂混合物的各种应用。
