PRECONCENTRATION OF MOLYBDENUM ON ACTIVATED CARBON FOR THE ANALYSIS OF SILICATES USING THE INJECTION METHOD IN FLAME ATOMIC-ABSORPTION SPECTROMETRY

An analytical procedure was developed for molybdenum determination in silicate geological materials by flame atomic absorption spectrometry (injection method), after sorption of the molybdenum-ammonium pyrrolidinedithiocarbamate complex on activated carbon. Sample pH, reagent and collector amounts and the presence of interfering species were studied. The method was applied to reference rock samples, interlaboratory comparison and real sample analysis. It is simple and cheap, and yields precise (RSD = 7%) and accurate results. The detection limit was determined to be 0.18 mu g g(-1). The procedure is applicable for the analysis of samples with molybdenum levels as low as 1 mu g g(-1).