Integrated identification and detection of hydration state and its evolution using terahertz technology

The accurate detection of dehydration processes in hydrated drugs can reveal various intermolecular vibration modes mediated by hydrogen bonds between water molecules and other components, which underpin the further development of pharmaceutical science, food safety and biophysics. Herein, terahertz (THz) technology is utilized to investigate the dehydration state of d(+)-Raffinose pentahydrate (Rf·5H₂O), in conjunction with imaging-based point by point scanning data acquisition and barcodes methods, to establish an innovative platform integrated identification, trace detection, and application capabilities. Our study demonstrates that the dehydration process of Rf·5H₂O can be dynamically monitored through the evolution of its THz absorption peaks, offering more precise results compared to XRD and Raman spectroscopies. Moreover, the absorbance spectra data collected at each individual pixel is utilized to build visualized THz images, achieving an ultralow minimum content required for detection of 0.032 μg/(50 μm)². Additionally, we introduce a THz spectra-barcode conversion system that not only ensures efficient electronic recordkeeping but also enhances user readability, thereby facilitating the practical applications of THz technology.