Determination of 13 toxic and physiological elements in herbs originating from China by ICPMS

The aim of the study was to develop an analytical procedure for determining 13 elements in 40 herbs and mixtures of herbs of Chinese origin by the ICPMS method after acidic digestion of samples. The correctness of the analytical procedure was verified by estimating the validation parameters. The traceability of a measurement result was established by the certified reference materials: Mixed Polish Herbs (INCT-MPH-2) Apple Leaves (1515 NIST) and Spinach Leaves (1570a NIST). Appropriate optimization has determined the sensitivity of determinations, precision, detection limits. The limits of detection were in the range 0.015-15 mg kg-1 for Co and Mg respectively, the precision was in the range 1% - 48% for Ba and Se, respectively, and the recoveries were in the range 69% - 101% for Ni and Mn, respectively. The determined content (mg kg-1) of elements in all samples was in the ranges: Mg (288-5755), V (<0.031-2.4), Mn (8.1-2095), Co (0.020-1.36), Ni (<1.1-6.9), Cu (<0.55-24), Zn (3.2-232), As (<0.096-1.4), Se (<0.15-0.85), Sr (1.1-277), Cd (<0.048-1.5), Ba (2.1-117) and Pb (<0.15-2.94). The content of As was higher than 0.25 mg kg-1 in 30% of the samples, the content of Cd was above the 0.2 mg kg-1 in 42.5% of the samples, and the content of Pb was above the value 0.3 mg kg-1 in 72.5% of the herbs. This means that the toxic elements were present in significant amounts able to cause toxic effects in the human body. Principal component analysis allowed us to distinguish 3 groups in which elements are well correlated: (i) V, As and Mg , (ii) Mn, Zn and Pb and (iii) Ni, Co and Cu.