Infrared Spectroscopy for Quality Control of Chinese Medicines

Infrared spectra of solid, liquid, and gas samples can be measured without separation or extraction. Most organic and inorganic molecules can generate fingerprint-like infrared spectral signals without derivation or labeling. As a result, infrared spectroscopy can directly characterize the holistic compositions of Chinese medicinal samples in their entirety. The directness of infrared spectroscopy brings the advantages of integrality and simplicity. On one hand, infrared spectroscopy can simultaneously profile inorganic molecules, organic small molecules, and macromolecules in one sample. This integrality advantage helps to control the unknown and unexpected ingredients that may contribute to the efficacy and safety of Chinese medicine. On the other hand, the chemical analysis and quality assessment by infrared spectroscopy can be performed quickly, on-site and on-line. This simplicity advantage helps to achieve the high-efficiency and low-cost quality control of Chinese medicine. The fundamental principles and methods of infrared spectroscopy for quality control of Chinese medicine were discussed in this article.