Analysis of pencil graphite samples of various origins using instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) was applied for multi-element determination in samples of graphite used in manufacturing of pencils. These samples have been randomly selected from the Egyptian market from different manufacturers and of various origins. Some of these samples are imported from the world market and the others are locally made. The determined elements in these samples were: As, Au, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Na, Ni, Rb, Sc, Ta, Th, U, W, Yb and Zn. Some of these elements were major or minor elements where others were trace elements. Standard reference material was used in this analysis. Some of the analyzed samples contain some toxic or undesirable elements such as As, Th and U. In addition some of these elements are present in comparatively high concentration.