Research Progress in the Analysis of Chemical Forms of Mercury in Traditional Chinese Medicine

A comprehensive evaluation of the chemical forms of heavy metals, rather than their total amount of elements, is the basis of the scientific and objective evaluation of safety in heavy metals. As mercury, the most toxic heavy metal in the environment (such as in water, soil, and air), accumulates in medicinal plants, chemical forms of mercury in medicinal plants and their preparation need to be clearly understood. This study aims to summarize the chemical status of mercury in bulk Chinese medicinal herbs and traditional Chinese medicine preparations and to discuss research methods for their analysis. Further, widespread high-performance liquid chromatography-inductively coupled plasma mass spectrometry, advanced synchrotron X-ray absorption fine structure spectroscopy, and X-ray fluorescence were used for the in situ analysis of the chemical state of mercury. The results were then analyzed to improve the analytical methods and evaluation standards for the chemical state of mercury in Chinese herbal medicines.