A review of the application of near-infrared spectroscopy to rare traditional Chinese medicine.

Near-infrared spectroscopy (NIRS) has become popular in the field of traditional Chinese medicine (TCM) due to its many practical advantages, such as providing rapid, accurate, and simultaneous analysis. This review is intended to provide up-to-date information on qualitative and quantitative NIRS analysis in TCM, especially rare TCM. By performing a substantial survey of the literature from China and abroad, we also combine our own studies on some rare TCMs using NIRS to review the application of NIRS in this field. Basic analytical methods and specific examples of NIRS demonstrates NIRS's ability in authenticity identification, species identification, geographic origin analysis, quantitative analysis, adulteration detection, rapid detection, and on-line monitoring of TCM, and illustrates the feasibility and effectiveness of NIRS applied in the quality control (QC) of TCM. Some disadvantages and prospects of NIRS are also discussed here in detail.