Multielements determination and metal transfer investigation in herb medicine Bupleuri Radix by inductively coupled plasma‐mass spectrometry

Bupleuri Radix is a famous traditional Chinese medicine (TCM) and an important raw material in TCM patent prescriptions. It is widely used in several countries, including China, Japan, South Korea, and America. However, the impact of heavy metal transfer rules on TCMs remains unknown. In this study, a total of 45 paired original medicines (OMs), decoction pieces (DPs), and vinegar‐processed (VPs) samples were simultaneously determined via inductively coupled plasma‐mass spectrometry after a microwave digestion. The concentrations of the elements were shown at three levels: (a) Al and Fe at the mg/g level; (b) Pb, Cu, Ba, Mn, Cr, and Ni at the mg/kg level; (c) Co, As, Cd, and Hg at μg/kg level. It is worth noting that the Cu levels were found to exceed the maximum concentration set by Chinese legislation (20.0 mg/kg). In addition, Mn, Ni, and Cu levels were higher in samples from the Gansu province than those from other provinces. The accumulation of the heavy metals decreased in the order of OMs > DPs > VPs; this was especially true for the Al and Fe levels. Furthermore, the results indicate that decocting the samples may reduce the intake of heavy metals. The element transfer ratios for decoctions were under 50% compared to herbal medicines and decreased in the order of Co > As > Mn > Hg > other metals. Our study strongly suggests that long‐term and regular monitoring for heavy metals in the plant is necessary.