The graphite phase has been extracted from the nodular cast iron to measure the concentration of trace element in it. The impurity phase was removed from the extracted matter by dissolving it with HCl and HCl+H₂O₂ to get the pure graphite phase. PIXE measurements were performed with thick targets of the pure graphite phase. Differences in the trace element concentrations between the graphite phase and the matrix have been observed. The effect of Ti and As in graphite phase on the nodularization rate and the mechanical properties have been studied.