ELIMINATION OF INTERFERENCES IN THE DETERMINATION OF ARSENIC AND DETERMINATION OF ARSENIC IN PERCOLATE WATERS FROM AN INDUSTRIAL LANDFILL BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

The determination of arsenic in environmental samples suffers interfer ence by chloride which gives rise to the polyatomic interference of (A rCl)-Ar-40-Cl-35 on As-75. Mathematical correction methods based on th e ratios (ArCl)-Ar-40-Cl-37/(ArCl)-Ar-40-Cl-35, (ClO)-Cl-35-O-16/(ArCl )-Ar-40-Cl-35 or (ClO)-Cl-37-O-16/(ArCl)-Ar-40-Cl-35, discussed and co mpared with each other. The method is applied to the determination of arsenic in treated percolate water from a landfill where arsenic conta ining waste is landfilled. The results obtained when applying the diff erent equations were in good agreement with each other. The results fo r the untreated percolate water, which could be diluted far enough to eliminate matrix effects and showed negligible interference from chlor ide, were in good agreement with results obtained with Capillary Zone Electrophoresis. Hydride generation made it possible to determine As(I II) and by difference As(V) in both waters. 99.7% of the arsenic prese nt in the percolate water was As(V), which means that during the landf illing, possibly by the infiltration of rainwater, the arsenic is oxid ised because the original industrial waste contained 100% As(III).