优化初始脉冲增强多量子跃迁及卫星跃迁魔角旋转谱灵敏度
收稿日期: 2015-03-23
修回日期: 2015-05-12
网络出版日期: 2015-06-05
基金资助
Sensitivity Enhancement of Multiple Quantum and Satellite Transition Magic Angle Spinning Spectra by Optimizing the Initial State
Received date: 2015-03-23
Revised date: 2015-05-12
Online published: 2015-06-05
Supported by
郑人豪 , 吴振 , 黄柏绮 , 柯志正 , 丁尚武* . 优化初始脉冲增强多量子跃迁及卫星跃迁魔角旋转谱灵敏度[J]. 波谱学杂志, 2015 , 32(2) : 363 -372 . DOI: 10.11938/cjmr20150218
A method to significantly enhance the sensitivity of the widely used multiple quantum magic angle spinning (MQMAS), satellite transition magic angle spinning (STMAS) and their variants is proposed. By introducing a preparatory period prior to the normal multiple quantum excitation or satellite transition pulse, the initial state can be optimized so that the recycle delay time can be substantially reduced. The performance of this method, for both MQMAS and
STMAS in two different magnetic fields, has been demonstrated with a number of representative nuclear species (23Na, 11B and 87Rb). This method can be implemented, without any additional hardware or software accessories, on all conventional solid-state NMR spectrometers with operating magnetic field as low as 4.7 T and sample spinning speed as slow as 6 kHz. Moreover, it is a very flexible method so that it can be customized, i.e., for individual compounds, the experimental parameters can be optimized for each compound following a step-by-step procedure specified in this work although a full theoretical exposition will be provided separately.
Key words： solid-state NMR; quadrupolar nuclei; MQMAS; STMAS; pulse optimization
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