Determination of heavy metals in chinese prickly ash from different production areas using inductively coupled plasma-mass spectrometry

Purpose: To determine the heavy metal content of Chinese prickly ash (CPA) produced in various areas of China. Methods: CPA samples collected from different production areas in China were subjected to microwave digestion, and the contents of copper (Cu), nickel (Ni), chromium (Cr), lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), tin (Sn), and antimony (Sb) were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Results: Heavy metal levels in the CPA samples followed the order: Cu (3.29-24.17 mg/kg) > Cr (0.04- 7.33 mg/kg) > Ni (0.88-6.86 mg/kg) > Pb (0.00-3.84 mg/kg) > As (0.0011-1.08 mg/kg) > Cd (0.029-0.211 mg/kg) > Sb (0.03-0.21 mg/kg) > Sn (0.00-0.15 mg/kg) > Hg (0.000-0.032 mg/kg). Metal-to-metal correlation studies showed that there were significant correlations between Cu-Cr (p = -4.02), Cu-Ni (p = 0.561), Cu-As (p = 0.554) and Ni-As (p = 0.428) at the 0.01 level. Also, some metal-to-metal correlations were observed in Pb-Cr (p = 0.351), Pb-Cu (p = -0.310), Sb-Cd (p = 0.322), Sb-Hg (p = 0.311) and Cd-Sn (p = 0.309) at the 0.05 level. The highest concentrations of Pb and As in CPA exceeded the maximum permissible limits in China. Based on current safety standards, the concentrations of heavy metals in these CPA samples mean they are safe for human consumption. Conclusions: The status of heavy metal concentrations of CPA should be further investigated in Sichuan, Shaanxi, Shanxi and Jiangsu. In addition, ICP-MS is a reliable and rapid technique for the determination of the heavy metals in CPA.