中文摘要：

维持血液的pH在7．35～7．45范围内，是生命的基本需要．人体生理状态的改变往往会伴随或者引发血液pH的变化．本文通过扩散加权、横向弛豫加权以及饱和转移差谱等^1H NMR方法，对pH7．0～7．8的血清体系进行研究，观察其中大分子和小分子代谢物的变化．实验结果表明pH的改变不仅能够引起血清中一些小分子代谢物化学位移的改变，还会影响小分子代谢物与蛋白的相互作用，引起这些小分子结合态和游离态含量的变化．此外，没有观察到血清蛋白信号的明显变化，仅血清白蛋白赖氨酰信号随pH增高有高场位移．

英文摘要：

Maintenance of acid-base homeostasis is vital for living organism. Changes of H＋ concentration （pH） in blood serum may result in adverse physiological consequences. In this study, the effects of pH changes on human blood serum were studied by T2-weighted and diffusion-weighted ^1 H NMR spectroscopy and saturation transferred difference （STD） experiments. The chemical shifts and concentrations of the metabolites in the serum were measured in serum samples with pH varied between 7.0 and 7.8. It was demonstrated that, from pH 7.0 to pH 7.8, the chemical shifts of many low molecular-weight metabolites drifted upfield and the intensities of phenylalanine, tyrosine, histidine, and lactate in the T2-weighted NMR spectra changed significantly. No significant changes in the protein signals were observed, except that the signal from albumin lysyl shifted towards upfield.