Yang Huiyu, Zhang Xinrui, Gao Yang, Peng Zhuang, Su Bo, Li Kai, Zhang Cunlin
Department of Physics, Capital Normal University, Beijing, China.
Beijing Key Laboratory for Terahertz Spectra and Imaging, Beijing, China.
Front Nutr. 2025 Jan 28;12:1532092. doi: 10.3389/fnut.2025.1532092. eCollection 2025.
Melatonin and 5-hydroxytryptophan (5-HTP), known for benefits in regulating sleep and combating depression, respectively, are incorporated into dietary supplements. Rapid and accurate identification of dietary supplement types and their contents remains a significant challenge in ensuring food safety.
In this study, qualitative and quantitative analysis of melatonin and 5-HTP was performed using Raman spectroscopy, powder X-ray diffraction (PXRD), and terahertz time-domain spectroscopy (THz-TDS). Purity and crystal structures of the samples were investigated using Raman spectroscopy and PXRD, establishing the foundation for terahertz (THz) simulations.
The Raman spectroscopy results demonstrate that the characteristic Raman peaks of melatonin and 5-HTP in the range from 170 cm to 1700 cm were observed at 1356 cm and 1,304 cm, respectively. Results of THz revealed that melatonin and 5-HTP each have five THz characteristic peaks, which distinguish these substances. The peak of melatonin at 1.23 THz shows a good linear fit with the mass fraction, while 5-HTP has a similar relationship at 1.14 THz. Then, L-tryptophan, a common contaminant in the production of melatonin and 5-HTP, was successfully identified within the mixture. Finally, it is demonstrated that THz technology can effectively detect melatonin and 5-HTP in commercial dietary supplements. This study establishes a rapid, efficient, and non-destructive approach for the regulation and quantitative analysis of dietary supplements.
褪黑素和5-羟色氨酸（5-HTP）分别以调节睡眠和对抗抑郁的功效而闻名，被添加到膳食补充剂中。快速准确地识别膳食补充剂的类型及其成分仍然是确保食品安全的一项重大挑战。
在本研究中，使用拉曼光谱、粉末X射线衍射（PXRD）和太赫兹时域光谱（THz-TDS）对褪黑素和5-HTP进行了定性和定量分析。利用拉曼光谱和PXRD研究了样品的纯度和晶体结构，为太赫兹（THz）模拟奠定了基础。
拉曼光谱结果表明，在170cm至1700cm范围内，褪黑素和5-HTP的特征拉曼峰分别出现在1356cm和1304cm处。太赫兹光谱结果显示，褪黑素和5-HTP各有五个太赫兹特征峰，这些峰可区分这两种物质。褪黑素在1.23THz处的峰与质量分数呈现良好的线性拟合，而5-HTP在1.14THz处有类似关系。然后，成功鉴定出褪黑素和5-HTP生产过程中的常见污染物L-色氨酸在混合物中的存在。最后，证明了太赫兹技术能够有效检测商业膳食补充剂中的褪黑素和5-HTP。本研究建立了一种快速、高效且无损的方法用于膳食补充剂的监管和定量分析。
