The proton beam from the 4 MV Van de Graaff at the University of Florida has been used in conjunction with a 5 mm thick lithium drifted silicon, Si (Li), x-ray detector to do elemental analysis of biomedical samples by proton-induced x-ray emission (PIXE). Several hundred samples, mostly autopsy organs ashed at high, temperature, have been analyzed by this method. The main object of the research is the correlation between human diseases and trace element levels. The target mass has been determined by monitoring the elastically scattered protons from the sample. This technique considerably reduces the target preparation time by eliminating careful weighings or doping of each individual sample.