New NMR Techniques Using Excitation Sculpting

在化学学部实验物理化学计划的这个项目中，Shaka将开发一种新的脉冲核磁共振（NMR）技术，称为激发雕刻。强直流磁脉冲场梯度（PFGs）将与频率扫描结合使用，以消除带外信号，显示所需的激励轮廓，与传统脉冲整形相比具有显著优势。初步结果表明，使用新技术可以有效地抑制水，其中与碳-12原子核结合的质子被抑制，而不会失去与碳-13键合的质子所期望的信号。结合优异的碳-13解耦，获得了极好的高分辨率吸收模式质子多重态。核磁共振波谱是化学家武器库中最有用的工具之一。不断发展的技术使这种方法能够应用于更多的问题，因此可以从核磁共振光谱中提取更多的信息，这些信息涉及诸如无机材料和重要的生物分子等不同的系统。在这项工作中开发的激发雕刻方法预计将对大多数重要的核磁共振实验产生重大影响，包括在各地核磁共振设施中进行的一些“常规”实验。

In this project in the Experimental Physical Chemistry Program of the Chemistry Division, Shaka will develop a new pulsed nuclear magnetic resonance (NMR) technique called excitation sculpting. Strong DC magnetic pulsed field gradients (PFGs) will be used in conjunction with frequency sweeps to eliminate out-of-band signals, revealing the desired excitation profile and resulting in significant advantages compared to conventional pulse shaping. Preliminary results show effective water suppression using the new technique, in which protons bound to carbon-12 nuclei are suppressed without loss of the desired signal from protons bonded to a carbon-13. Combined with superior carbon-13 decoupling, superb high-resolution absorption-mode proton multiplets are obtained. Nuclear magnetic resonance spectroscopy is one of the most useful tools in the chemist's arsenal. Techniques are constantly being developed which allow this method to be applied to more problems, so that more information can be extracted from NMR spectra with respect to such varied systems as inorganic materials and biologically important molecules. The excitation sculpting method being developed in this work is expected to have a large impact on most important NMR experiments, including some `routine` experiments carried out in NMR facilities everywhere.