An optimized buffer system for NMR-based urinary metabonomics with effective pH control, chemical shift consistency and dilution minimization
An optimized buffer system for NMR-based urinary metabonomics with effective pH control, chemical shift consistency and dilution minimization
复制标题
用于基于 NMR 的尿液代谢组学的优化缓冲系统，具有有效的 pH 控制、化学位移一致性和稀释最小化
DOI：
10.1039/b818802e
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发表时间：
2009-01-01
期刊：
影响因子：
4.2
通讯作者：
Tang, Huiru
中科院分区：
文献类型：
--
作者：
Xiao, Chaoni;Hao, Fuhua;Tang, Huiru
基于核磁共振的代谢组学已被广泛用于理解应激源对哺乳动物代谢的扰动。然而，代谢物的样本间化学位移变化仍然是有效数据挖掘的一个突出问题。在这项工作中，我们系统地研究了pH和离子强度对9种尿代谢物混合物的化学位移的影响。我们发现，化学位移随pH的升高而减小，但随离子强度的增加而增大，这可能是由于pH和离子强度引起官能团的电离平衡改变所致。我们还发现，当pH值为7.17.7，盐浓度小于0.15M时，大多数代谢物的化学位移变化小于0.004 ppm。在后续优化的基础上，提出了一种新的缓冲体系，该体系由K2HPO4和NaH2PO4(pH 7.4，1.5M)组成，缓冲体积比为1：10，用于人体尿液代谢组学研究；我们建议在多变量数据分析之前，特别是在使用高分辨率数据时，对柠檬酸的质子信号和组氨酸的芳香信号的化学位移进行校正。在此基础上，建立了一种用于尿液代谢组学研究的优化样品制备方法。
NMR-based metabonomics has been widely employed to understand the stressor-induced perturbations to mammalian metabolism. However, inter-sample chemical shift variations for metabolites remain an outstanding problem for effective data mining. In this work, we systematically investigated the effects of pH and ionic strength on the chemical shifts for a mixture of 9 urinary metabolites. We found that the chemical shifts were decreased with the rise of pH but increased with the increase of ionic strength, which probably resulted from the pH- and ionic strength-induced alteration to the ionization equilibrium for the function groups. We also found that the chemical shift variations for most metabolites were reduced to less than 0.004 ppm when the pH was 7.1-7.7 and the salt concentration was less than 0.15 M. Based on subsequent optimization to minimize chemical shift variation, sample dilution and maximize the signal-to-noise ratio, we proposed a new buffer system consisting of K2HPO4 and NaH2PO4 (pH 7.4, 1.5 M) with buffer-urine volume ratio of 1 : 10 for human urinary metabonomic studies; we suggest that the chemical shifts for the proton signals of citrate and aromatic signals of histidine be corrected prior to multivariate data analysis especially when high resolution data were employed. Based on these, an optimized sample preparation method has been developed for NMR-based urinary metabonomic studies.