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J Magn Reson. 2011 Dec;213(1):107-11. doi: 10.1016/j.jmr.2011.09.016. Epub 2011 Sep 10.
Maximum-Quantum (MaxQ) NMR is an approach that exploits the simple lineshape (a singlet) of the highest possible coherence quantum order for a given spin system to help resolving the interpretation of the spectrum of complex mixtures. In this setup, resolution in the indirect, multiple-quantum, dimension is crucial, and it may be linked to a long duration of the signal acquired along this axis. We explored if this boundary on the length of the indirect dimension could not necessarily translate into extended experimental times by applying Non-Uniform Sampling (NUS) schemes in conjunction with Recursive Multi-Dimensional Decomposition (R-MDD) data processing. The actual value of the MaxQ order depends on the size of the spin system, so that for a mixture several MQ correlation spectra must be recorded to detect all possible molecular fragments. As the sparseness of the MQ datasets vary dramatically in going from higher (sparser) to lower (denser) coherence orders, the optimal compressing conditions and the fidelity of NUS/R-MDD scheme may vary along the series of MQ spectra. The NUS-MaxQ approach is demonstrated on the aromatic region of the 1H spectrum of a mixture of 10 simple aromatic molecules.
最大量子（MaxQ）NMR 是一种方法，它利用给定自旋系统中可能的最大相干量子数量的简单线形状（单峰）来帮助解析复杂混合物的光谱。在这种设置中，间接的、多重量子维度的分辨率至关重要，并且它可能与沿着该轴获取的信号的长时间有关。我们通过在递归多维分解（R-MDD）数据处理中结合非均匀采样（NUS）方案，来探索间接维度长度的这个限制是否不一定会转化为扩展的实验时间。最大量子数量的实际值取决于自旋系统的大小，因此对于混合物，必须记录多个 MQ 相关光谱才能检测到所有可能的分子片段。由于从较高（较稀疏）到较低（较密集）相干顺序的 MQ 数据集的稀疏性变化很大，因此最佳压缩条件和 NUS/R-MDD 方案的保真度可能会沿着 MQ 光谱系列变化。NUS-MaxQ 方法在 10 种简单芳香族分子混合物的 1H 光谱的芳香区域得到了证明。
