定量核磁技术参数的优化及其在中草药定量分析领域的应用

Optimization of experimental parameters for quantitative NMR(qNMR) and its application in quantitative analysis of traditional Chinese medicines

定量核磁技术是基于核磁共振原理的一种定量分析方法。该方法无需待测物对照品,解决了中草药定量研究中对照品缺乏的难题,并且操作简便快速、对检测样品无破坏性、准确度高、重现性好,相比于经典的高效液相色谱法、液质联用及气质联用等定量技术具有独特的优势。随着核磁技术的进步,核磁的灵敏度有了很大的提高,这在一定程度上增加了定量核磁技术的准确度。另外,选择合适的参数,对于获得高精准度的定量结果也至关重要。本文针对目前定量核磁技术中应用的最为广泛的定量氢谱技术(qHNMR)进行了综述,包括qHNMR的基本原理、影响qHNMR准确度的各项参数(包括信噪比、弛豫延迟时间、脉冲宽度、采集时间、窗函数、基线校正、相位校正等)、优化方法,以及qHNMR在中草药单一或多成分的含量测定、对照品的纯度检测和在食品分析领域的应用进展情况等。另外,对于定量核磁技术存在的问题及在中草药分析领域的应用前景也进行了讨论和展望。

Quantitative NMR （qNMR） is a technology based on the principle of NMR. This technology does not need the references of the determined components, which supplies a solution for the problem of reference scarcity in the quantitative analysis of traditional Chinese medicines. Moreover, this technology has the advantages of easy operation, non-destructiveness for the determined sample, high accuracy and repeatability, in comparison with HPLC, LC-MS and GC-MS. NMR technology has achieved quantum leap in sensitivity and accuracy with the development of NMR hardware. In addition, the choice of appropriate experimental parameters of the pre-treatment and measurement procedure as well as the post-acquisition processing is also important for obtaining high-quality and reproducible NMR spectra. This review summarizes the principle of qHNMR, the various experimental parameters affecting the accuracy and the precision of qHNMR, such as signal to noise ratio, relaxation delay, pulse width, acquisition time, window function, phase correction and baseline correction, and their corresponding optimized methods. Moreover, the application of qHNMR in the fields of quantitation of single or multi-components of traditional Chinese medicines, the purity detection of references,and the quality analysis of foods has been discussed. In addition, the existing questions and the future application prospects of qNMR in natural product areas are also presented.