Monitoring of toxic heavy metals contamination in commonly used Chinese materia medica

Abstract

Monitoring of toxic heavy metals (THMs) contamination, including lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg), for the quality control in Chinese materia medica (CMM) is critical for ensuring safe medication use in the pharmaceutical industry. A validated inductively coupled plasma–mass spectrometry method was used to determine THMs content in 1887 samples for 27 selected types of commonly used CMM. The correlation coefficient of the calibration curves for four THMs was higher than 0.995, indicating that the linearity is fine. The recovery rate was ranged in 82.6–105.4% for four THMs. The percentage of RSD in inter-day and intra-day precision test for four THMs was all lower than 10%. The limit of quantitation in test solution for Pb, As, Cd and Hg was 0.212, 0.500, 0.038, 0.044 μg/L, indicating that this validated ICP-MS method exhibited excellent sensitivity. Among these THMs, Pb and Cd are the most abundant contaminants in 27 selected types of CMM. In diverse permissible limits (PL) established by different countries/organizations, Cinnamomi ramulus and Eucommiae cortex usually exceeded the PL of 0.3 μg/g for Cd and occasionally exceeded the PL of 5.0 μg/g for Pb. Chuanxiong rhizome seldom exceeded the PL of 1.0 μg/g for Cd. Eucommiae cortex, Raphani semen, Atractylodis macrocephalae rhizoma and Bupleuri radix occasionally exceeded the PL of 0.3 μg/g for Cd. In conclusion, we hope to raise awareness of THMs contamination in commonly used CMM that affects safe medication use among farmers, manufacturer, and consumers.