Biomolecular NMR spectroscopy requires large magnetic field strengths for high spectral resolution. Today’s highest fields comprise proton Larmor frequencies of 1.2 GHz and even larger field strengths are to be expected in the future. In protein triple resonance experiments, various carbon bandwidths need to be excited by selective pulses including the large aliphatic chemical shift range. When the spectrometer field strength is increased, the length of these pulses has to be decreased by the same factor, resulting in higher rf-amplitudes being necessary in order to cover the required frequency region. Currently available band-selective pulses like Q3/Q5 excite a narrow bandwidth compared to the necessary rf-amplitude. Because the maximum rf-power allowed in probeheads is limited, none of the selective universal rotation pulses reported so far is able to cover the full \(^{13}\)C aliphatic region on 1.2 GHz spectrometers. In this work, we present band-selective 90° and 180° universal rotation pulses (SURBOP90 and SURBOP180) that have a higher ratio of selective bandwidth to maximum rf-amplitude than standard pulses. Simulations show that these pulses perform better than standard pulses, e. g. Q3/Q5, especially when rf-inhomogeneity is taken into account. The theoretical and experimental performance is demonstrated in offset profiles and by implementing the SURBOP pulses in an HNCACB experiment at 1.2 GHz.

生物分子 NMR 光谱需要大磁场强度才能获得高光谱分辨率。今天最高的场包括 1.2 GHz 的质子拉莫尔频率，预计未来会出现更大的场强。在蛋白质三重共振实验中，需要通过选择性脉冲激发各种碳带宽，包括大的脂肪族化学位移范围。当光谱仪场强增加时，这些脉冲的长度必须减少相同的因子，导致需要更高的射频振幅才能覆盖所需的频率区域。与必要的射频幅度相比，当前可用的频带选择脉冲（如 Q3/Q5）激发的带宽较窄。因为探头允许的最大射频功率是有限的，\(^{13}\) 1.2 GHz 光谱仪上的 C 脂肪族区域。在这项工作中，我们提出了带选择性 90° 和 180° 通用旋转脉冲（SURBOP90 和 SURBOP180），它们具有比标准脉冲更高的选择性带宽与最大射频振幅的比率。仿真表明这些脉冲的性能优于标准脉冲，例如 Q3/Q5，尤其是在考虑射频不均匀性时。理论和实验性能在偏移剖面中以及通过在 1.2 GHz 的 HNCACB 实验中实施 SURBOP 脉冲得到证明。