COMPARISON OF PALLADIUM NITRATE AND CHLORIDE AS A CHEMICAL MODIFIER FOR THE DETERMINATION OF LEAD IN SOLUTIONS AND SOIL SLURRIES BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

A systematic study of various amounts of Pd - Mg nitrates mixtures as a chemical modifier for the determination of Pb in aqueous solutions and soil slurries was conducted. The results were compared with similar work carried out with Pd as the chloride. In both solutions and slurries, small amounts of Pd (in either form) effectively delayed the atomisation for Pb until furnace conditions were nearly isothermal. The presence of Mg was required in order to avoid a reduction in the analyterecovery. The use of 0.6 μg of Pd + 1.0 μg of Mg was suitable, irrespective of the form of Pd. However, compared with PdCl2, larger amounts of Pd(NO3)2 could be tolerated without decreasing the sensitivity, provided larger amounts of Mg or a higher atomisation temperature was used.