Exploring the potential of terahertz time-domain spectroscopy for label-free identification of animal origin of chondroitin sulfate

Abstract

This study developed a simple method to distinguish the animal source of chondroitin sulfate (CS) through systematic investigations and comparisons of the terahertz (THz) spectral characteristics of CS with different animal sources. CS from shark had the lowest THz absorption coefficient, followed by that from cattle, with CS from piglet exhibiting the highest values. Meanwhile, in case of continuous and no heating, the changing trends of the THz absorption index value of CS from shark source exhibited significant changes, followed by that from cattle and piglet. Based on the Raman spectrum, infrared spectrum, and thermogravimetric analysis, the molecular composition and structure differences between them were the primary causes of the observed results, being related to the physical index of production by different manufacturers. Thus, the THz spectral characteristics of CS exhibit obvious species differences, which can be used in qualitative animal origin identification.

Keywords

• Terahertz spectroscopy
• Chondroitin sulfate
• Animal origin identification
• Variable temperature experiment
• Absorption coefficient