College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, PR China.
College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, PR China; Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Jul 5;275:121150. doi: 10.1016/j.saa.2022.121150. Epub 2022 Mar 15.
Under heating conditions, L-Glutamic acid (L-Glu) can be dehydrated to form L-pyroglutamic acid (L-PGA), and L-PGA can racemize to form DL-PGA. Here, we characterized this transformation at different temperatures and times by terahertz time domain spectroscopy (THz-TDS). By Powder X-ray diffraction (PXRD), the validity of THz spectroscopy is verified. The results prove that the reaction rate of dehydration and racemization is significantly affected by temperature. The THz spectra divided the reactions into three stages. At 150-155 °C, the reaction changes drastically. Furthermore, we found that the absorption intensity at 0.97 and 1.55 THz has a good dependence on the reaction temperature and time, showing a non-linear relationship (R > 0.98). Our findings suggest that the chemical transformation and reaction rate can be sensitively probed by terahertz spectroscopy, which provides a potential method for the quantitative analysis of reaction products.
在加热条件下，L-谷氨酸（L-Glu）可以脱水形成 L-焦谷氨酸（L-PGA），L-PGA 可以外消旋化形成 DL-PGA。在这里，我们通过太赫兹时域光谱（THz-TDS）在不同温度和时间下对这种转化进行了表征。通过粉末 X 射线衍射（PXRD）验证了太赫兹光谱的有效性。结果证明，脱水和外消旋化的反应速率受温度的显著影响。THz 光谱将反应分为三个阶段。在 150-155°C 时，反应发生剧烈变化。此外，我们发现 0.97 和 1.55 THz 处的吸收强度与反应温度和时间具有良好的依赖性，呈非线性关系（R>0.98）。我们的研究结果表明，太赫兹光谱可以灵敏地探测化学转化和反应速率，为反应产物的定量分析提供了一种潜在的方法。
