Application of nondestructive X-ray fluorescence analysis to determine the element composition of medicinal plants

A nondestructive X-ray fluorescence technique has been developed to determine Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Ba, and Pb in plants. The line element intensities were measured by an S4 Pioneer X-ray sequence spectrometer (Bruker AXS, Germany). The inversely proportional relationship was obtained between the analyte line intensity and mass of the plant, pressed on boric acid backing, for elements with an atomic number 11 < Z < 20. It was found that reduction of plant mass from 6 to 1 g leads to an increase in element determination sensitivity. The detection limits for 1 g of pressed plant were evaluated as μg/g: 5–20 (Na, Mg, Al); 1–4 (Si, P, S, Cl, K, Ca, Ti, Ba, Pb); 0.4-0.8 (Cr, Mn, Fe, Ni, Br, Cu, Zn, Rb and Sr). This technique was applied to determine the element composition of violets of Violaceae family, which are used in medicine.