A study of trace elements in some medicinal plants

Twenty one medicinal plants (herbal) have been investigated for major, minor and trace elements using the proton induced X-ray emission (PIXE) method. The samples were collected from the local market in Dhaka city and they were analysed by the thick-target external beam technique of the PIXE method. The samples were exposed to the proton beam as 1-mm thick pellet 0 f 7 mm dia. and irradiated with 2.0 MeV proton having 10 nA beam intensity. for 10-20 μC irradiation, the concentration of 15 elements,K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Sr, Zr and Pb were measured by comparison with calibration factors obtained from a curve constructed on the basis of the NBS orchard leaf standard (SRM-1571) irradiated under identical experimental condition. The concentration of K and Ca observed in the samples were in the range of 0.34-5.96% and .11-3.98% respectively. For Mn, Fe, Cu, Zn, Cr, As and Pb the concentration ranges were 4.1-1100, 60-7600, 1.1-276, 7-164, 1.2-48, 1.1-31, and 3.1-128 mg/kg respectively. Ti, Br, Rb, Sr and Zr were also determined with variable accuracy. The validity of the procedure was established by analysing a NIST standard (tomato leaf). The results obtained were in good agreement with the certified values. 17 refs.,3 tables, 3 figs