Variation of trace element contents in a single human liver

Multi element analysis of homogenised samples taken from three different areas of a single human liver was performed for 18 elements by proton induced X-ray emission (PIXE). Small (10--20%) but statistically significant variations between the element contents of these areas were found for Cl, K, Ca, Fe, Cu, Zn, Br, Rb and Mo. These differences are not parallel to each other. The variation of element content within one area of this single liver did not show any distinct correlation between different elements, nor did it significantly exceed the methodical errors of 3--10% except for lead. Thus we conclude from our measurements that the trace element analysis of small liver samples by PIXE is, with the exception of lead, fairly representative for the whole organ.