Development of a Unified X-ray Fluorescence Procedure for Determining Heavy Metals in Biological Materials

A unified procedure for the X-ray fluorescence determination of Pb, Mo, Rb, As, Zn, Ni, Fe, and Mn in biological materials was developed using the internal standard technique (gallium was the reference element). The samples were prepared for analysis by ashing the materials. The effects of variations in the chemical composition and of the surface density of unsaturated radiators on the accuracy of the analytical results were studied with the use of theoretical intensities; this effect varied from 2.5 to 22%. Based on this information, an optimum calibration function was chosen. Ashes of plant and animal tissues can be analyzed with the use of this function. The errors due to sample preparation for analysis and the reproducibility and accuracy of the results of X-ray fluorescence analysis were evaluated.