柠檬酸锌二水合物太赫兹光谱及失水动力学研究

Terahertz spectroscopy detection of zinc citrate dihydrate and its dehydration kinetics

摘要:

利用太赫兹时域光谱技术(THz-TDS)对柠檬酸锌二水合物晶体及其失水动力学进行准确、无标记检测。实验结果表明，室温下柠檬酸锌二水合物有2个明显的吸收峰：一个主峰在1.91 THz，一个次峰在1.77 THz。随着温度升高，柠檬酸锌二水合物吸收主峰强度不断减少，直至消失。根据柠檬酸锌二水合物在1.91 THz处的特征吸收峰面积在不同温度、不同加热时间的变化关系，利用阿伦尼乌斯方程得到柠檬酸锌二水合物转变成无水合物的焓变为381.13 J/g(232.6 kJ/mol)，与传统差示扫描量热法(DSC)相比测量误差为4.2%。这些结果表明，THz-TDS可以提供一种快速、有效的结晶水合物焓变检测方法。

Abstract:

Terahertz Time Domain Spectroscopy(THz-TDS) is employed to detect the Zinc Citrate(ZC) dihydrate and its dehydration kinetics. Results show that there are two prominent absorption peaks:one at 1.91 THz, the other at 1.77 THz for the ZC dihydrate, while there is no featuring absorption peak for ZC anhydrate at room temperature. When the temperature increases, the absorption peak of ZC dihydrate at 1.91 THz decreases and gradually disappears. According to the variation of the absorption peak area of ZC dihydrate at 1.91 THz under different temperatures and heating time, the enthalpy change of ZC dihydrate transforming to anhydrate is 381.13 J/g(232.6 kJ/mol) by using the Arrhenius equation, and the error is 4.2% compared with the traditional Differential Scanning Calorimetry(DSC) measurement. These results indicate that THz-TDS can be used as an efficient and fast technique for the detection of ZC dihydrate and its dehydration kinetics.