Simultaneous determination of heavy metal pollution in commercial traditional Chinese medicines in China

A rapid and accurate method of quantifying heavy metal pollution in commercial traditional Chinese medicines (TCMs) is described. The method uses modified wet digestion for sample preparation and atomic absorption spectrophotometry for detecting the content of copper (Cu), cadmium (Cd), arsenic (As), lead (Pb) and mercury (Hg). The determination limits of the method were 0.001, 0.002, 0.001, 0.001 and 0.001 mg/kg for Cu, Cd, As, Pb and Hg, respectively. The method was applied to the quantification of heavy metal pollution in 50 different commercial TCMs in a total of 250 samples. Heavy metal contents in the samples investigated were found at different levels. The level of As did not exceed the legal limit stated in the China pharmacopoeia 2010, whereas Cu, Cd, Pb and Hg were above permitted levels in some samples.