Abstract

The main reason for the alternation of terahertz (THz) response in biological samples is the transition of a part of water from its free to bound state and back. To analyze such results, a precise spectrum of bound water within THz range should be known. The suggested wet powder spectroscopy method is optimal for this task. We measured the THz transmission of dry glucose pressed into pellets. Then, we added a small amount of water to these pellets and again measured the THz spectra. The contribution from the free water state starts to appear in resulting THz spectra after water concentration in glucose samples reaches 14–16%. Just below is the optimal point to extract the spectral contribution from bound water. We extracted the absorption and refraction spectra of bound water and confirmed that they are an order of magnitude weaker than those of free water within 0.07–1-THz range.

中文翻译：

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葡萄糖中结合水的太赫兹光谱：从结晶状态到溶解状态的直接测量

摘要

生物样品中太赫兹（THz）响应交替发生的主要原因是一部分水从其自由态过渡到结合态再返回。为了分析这样的结果，应该知道在THz范围内结合水的精确光谱。建议的湿粉光谱法最适合此任务。我们测量了压成颗粒的干葡萄糖的THz透射率。然后，我们向这些颗粒中加入少量水，然后再次测量THz光谱。在葡萄糖样品中的水浓度达到14–16％之后，游离水态的贡献开始出现在最终的THz光谱中。在下面的是从结合水中提取光谱贡献的最佳点。