DETERMINATION OF TRACE-ELEMENTS IN HIGH-PURITY MOLYBDENUM TRIOXIDE BY SLURRY SAMPLING ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

A method for the direct determination of Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na and Ni in high-purity molybdenum trioxide by slurry sampling electrothermal atomic absorption spectrometry is described. As a result of the substantial blank reduction achieved by using 'selected pots' for the performance of the slurry sampling technique, in the case of elements with high overall concentrations such as Ca, K, Mg and Na, the detection limits can be improved by two orders of magnitude, as compared with the dissolution procedure, reaching 2, 1, 0.5 and 1 ng g-1 for Ca, K, Mg and Na, respectively. Control of the blank for both the solution and the slurry techniques, the background attenuation caused by the molybdenum matrix and sample homogeneity are discussed.