Continuous-wave terahertz spectroscopy for quantitative analysis and physical characterization of α-lactose

Abstract

In this study, the quantitative concentration of α-lactose was analyzed using continuous-wave terahertz spectroscopy. The effect of compressive strength on the physical properties and spectral changes of the material was also evaluated. Conventional FT-IR and Raman spectroscopy suffer from limitations such as water interference, fluorescence interference, and sample deformation. To circumvent these limitations, continuous-wave terahertz spectroscopy was employed. α-lactose samples were pelletized at varying concentrations (0.1–90 wt%) and compressive strengths. The experimental findings revealed a concentration-dependent absorption peak shift at 0.532 THz in the terahertz-wave region, indicating a strong linear correlation between concentration and absorbance ($R_{\mathrm{adj}}^2$ = 0.991). The study identified 60 kilonewton as the optimal compressive strength, ensuring the structural stability of the samples and reliability of the data. These findings indicate that continuous wave terahertz spectroscopy can be effectively employed for the nondestructive and precise quantitative analysis of α-lactose (0.5 wt%). Consequently, this method is expected to be utilized as a quality control and ingredient detection technique in food and pharmaceutical industries.